GARN® WHS | Hydronic System Design Manual

GARN® System Design Manual

Hot Water Supply 2” FPT

Hot Water Return 1- 1/2” MPT

DECTRA CORPORATION • 3425 33rd Ave NE • St Anthony, Minnesota 55418 Phone: 612-781- 3585 • Fax: 612 -781- 4236 • www.garn.com

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

The GARN® unit, all related heating equipment (including pumps, piping, fan coils, hot water baseboard, radiant floor heating systems, etc) and all electrical equipment (including power wiring, controls, control wiring, back up electric heating, etc) must be installed by a qualified installer or competent licensed personnel in strict compliance with all Federal, State and local codes. All electrical equipment, devices and wiring installed with the GARN® unit must be UL listed . Installer to supply and install all code required electrical over current and disconnect devices.

Table of Contents

A. SYMBOLS, ABBREVIATIONS, and safety symbols: .......................................................................................... 4

B. PROMOTING CONSERVATION AND EFFICIENCY BEFORE ANYTHING ELSE: ..................................................... 5

PROBLEMS WITH IMPROPERLY COMBUSTED FUEL: .................................................................................................5 HEATING A SWIMMING POOL: .................................................................................................................................5

C. RULES OF THUMB FOR AN INITIAL ESTIMATE OF EQUIPMENT SIZE ............................................................... 6

COMMERCIAL HEAT LOSS: ........................................................................................................................................6 RESIDENTIAL HEAT LOSS EXCLUDING VENTILATION:................................................................................................6 RESIDENTIAL VENTILATION:......................................................................................................................................6 RESIDENTIAL DOMESTIC WATER HEATING: ..............................................................................................................7 HOT TUB HEATING: ...................................................................................................................................................7 RADIANT FLOOR HEATING: .......................................................................................................................................7 FORCED AIR HEATING: ..............................................................................................................................................8 HOT WATER BASEBOARD HEATING: .........................................................................................................................9 GLYCOL CORRECTION FACTORS AND FREEZE PROTECTION TABLES:......................................................................10 The difference between freeze and burst protection: (DOW Chemical)..............................................................11 PUMP LAWS AND FAN LAWS: .................................................................................................................................11

D. PIPING AND PUMP SIZING ........................................................................................................................... 12

PIPING DESIGN AND CALULCATION GUIDELINES....................................................................................................12 EQUIVALENT FEET OF PIPE FOR SCREWED FITTINGS AND VALVES.....................................................................12 EQUIVALENT FEET OF PIPE FOR PEX FITTINGS ....................................................................................................13 Flow and heat capacity @ 4' of head loss per 100' of pipe length ......................................................................13 Flow and heat capacity @ 6' of head loss per 100' of pipe length ......................................................................14 PRESSURE LOSS CHARTS: STEEL, COPPER, PEX....................................................................................................15 PIPING INSTALLATION AND HOOKUP GUIDELINES .................................................................................................16 PLUMBING WITH COPPER:..................................................................................................................................16 PLUMBING WITH STEEL: .....................................................................................................................................16 CALCULATION OF NET POSITIVE SUCTION HEAD FOR PUMPS ...............................................................................17 UNDERGROUND PIPING: ......................................................................................................................................... 19 DRY AREA BURIED PIPING DIAGRAM: .................................................................................................................19 MOIST AREA BURIED PIPING DIAGRAM:.............................................................................................................20 ROADWAY AND PARKING LOT BURIED PIPING DIAGRAM: .................................................................................21 PUMP SELECTION AND INSTALLATION GUIDELINES: ..............................................................................................21

E. SYSTEM DISTRIBUTION CONNECTION AND SCHEMATICS ............................................................................ 23

ZERO PRESSURE, FIXED TEMP - PRIMARY ONLY PUMPING: ...................................................................................23 ZERO PRESSURE, FIXED SUPPLY TEMP – PRIMARY SECONDARY PUMPING: ..........................................................24 ZERO PRESSURE, MULTIPLE ZONE – PRIMARY SECONDARY PUMPING:.................................................................25 CONNECTING TO AN EXISTING PRESSURIZED OR GLYCOL TREATED DISTRIBUTION SYSTEM: ...............................27

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

PRESSURIZED, FIXED SUPPLY TEMP – CONSTANT SPEED PUMPING ......................................................................28 PRESSURIZED, FIXED SUPPLY TEMP – VARIABLE SPEED PUMPING.........................................................................29

F. SYSTEM COMPONENT CONNECTION AND SCHEMATICS .............................................................................. 30

CONNECTION TO FORCED AIR FURNACE: ...............................................................................................................30 FORCED AIR GUIDELINES:....................................................................................................................................30 COIL SELECTION...................................................................................................................................................31 HIGH LIMIT SWITCH (DUCT STAT) .......................................................................................................................31 BLOWER SPEED AND CFM ADJUSTMENT............................................................................................................31 CONNECTION TO HOT WATER BASEBOARD SYSTEM: ............................................................................................32 HOT WATER BASEBOARD GUIDELINES ...............................................................................................................32 NEW CONSTRUCTION .........................................................................................................................................33 CONVERTING AN EXISTING BASEBOARD SYSTEM ...............................................................................................33 CONNECTION TO HYDRONIC RADIANT FLOOR SYSTEM: ........................................................................................34 RADIANT FLOOR GUIDELINES: ............................................................................................................................34 CONNECTION TO AN EXISTING PRESSURIZED SYSTEM ...........................................................................................35 WATER TO WATER FLAT PLATE HEAT EXCHANGERS...........................................................................................36 CONNECTION TO AN ELEVATED SYSTEM ................................................................................................................37 CONNECTION TO DOMESTIC HOT WATER ..............................................................................................................37 SOLAR INTERFACE: ..................................................................................................................................................39

G. BACKUP HEATING WITH THE EXISTING SYSTEM OR ELECTRIC...................................................................... 40

H. EXAMPLE PROBLEM – HOUSE WITH REMOTE POLE BARN/WORKSHOP ...................................................... 41

EXAMPLE PROBLEM SETUP:....................................................................................................................................41 HOUSE DESIGN: ....................................................................................................................................................... 41 MAIN FLOOR DESIGN: .........................................................................................................................................41 BASEMENT LEVEL DESIGN:..................................................................................................................................43 SIZE THE main floor HOUSE PUMP..........................................................................................................................43 SIZE THE BASEMENT PUMP ....................................................................................................................................44 DISTRIBUTION PIPE AND PUMP SIZING ..................................................................................................................44 SIZE DISTRIBUTION PUMP.......................................................................................................................................45 POLE BARN DESIGN.................................................................................................................................................45 SIZE POLE BARN PUMP ...........................................................................................................................................46

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

A. SYMBOLS, ABBREVIATIONS, AND SAFETY SYMBOLS:

ABBREVIATIONS

SYMBOLS

BTUH

BTU’s p er hour

Pump

EWT

Entering Water Temperature

Strainer

FPS

Feet per second

Flow Arrow

FPT

Female Pipe Thread

Mixing Valve

GPM

Gallons per minute

Isolation Valve

HWS/HWR Hot Water Supply/Hot Water Return

Flange

MBH

MBTU’s (1,000 BTU) per hou r

Thermometer

MMBH

MMBTU (1,000,000 BTU) per hour

Temperature Sensor

MPT

Male Pipe Thread

Check Valve

NPT

National Pipe Thread

Drain

Outdoor

Connect to Existing

RWT

Return Water Temperature

A notice provides a piece of information to make a procedure easier or clearer.

A caution emphasizes where equipment damage might occur. Personal injury is not likely.

A warning emphasizes areas where personal injury or death may occur but is not likely. Property or equipment damage is likely.

A danger emphasizes areas or procedures where death, serious injury, or property damage is likely if not strictly followed

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

B. PROMOTING CONSERVATION AND EFFICIENCY BEFORE ANYTHING ELSE:

PROBLEMS WITH IMPROPERLY COMBUSTED FUEL: Improperly combusted wood fuel emissions are toxic to humans and animals. These emissions include: finely atomized liquid oils (creosote), very fine particulates, aromatic hydrocarbons, polycyclic organic matter, carbon dioxide, and carbon monoxide. In fact, population densities in suburban and urban locations create significant local air shed pollution issues that essentially preclude the use of coal, wood and other fuels. Complete combustion reduces these by-products significantly. BUT! Remember this: Eliminating fuel usage is the same as burning fuel with absolutely zero emissions , impossible for any fuel, even natural gas! A well designed and constructed energy efficient building can reduce heating demand and fuel usage by at least half or more when compared to a “code built house.” By following the simple suggestions below, you will reduce fuel usage and annual fuel bills, create a comfortable and healthy environment for the occupants, contribute to a healthier local air shed, and realize a reasonably quick return on investment.

Install good insulation and caulking.



 Install double glazed, argon filled energy efficient windows (or better).  Install insulated thermally efficient doors and storm doors, with good quality weather stripping.  Install an air-to-air heat exchanger (heat recovery ventilator) to provide ventilation.  Insulate and caulk all rims joists.  Insulate basements walls from floor to ceiling with methods that prevent the formation of mold and mildew.  Utilize passive solar techniques whenever possible.  Install water saving toilets, showers and faucets throughout.  If you have access to natural gas, use a high efficiency natural gas condensing furnace or boiler to provide s pace and domestic water heating. Don’t burn wood unless you want to.  Install only high SEER air conditioning equipment with variable speed fans to effectively control indoor relative humidity. HEATING A SWIMMING POOL: This is best accomplished with solar heating and an evaporation prevention blanket. Solar heating has proven cost effective, dependable and efficient for many years in many countries. Solar heating is efficient in almost every area of the US. Most people do not realize that a swimming pool requires a heater that may be several times the size and capacity of their residential space heater. However, during the spring, summer and fall the amount of energy required to heat a pool is easily provided by solar panels. For more information on solar pool heating products visit:

http://www.heliocol.com/ http://www.aetsolar.com/ http://www.h2otsun.com/

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

C. RULES OF THUMB FOR AN INITIAL ESTIMATE OF EQUIPMENT SIZE

The following are approximate values that may be used to estimate the size of the primary wood heating equipment. Once a project is given the “go ahead” an exact heat loss should be calculated according to ASHRAE Fundamentals or Manual J methods to ensure correct sizing. Over-sizing equipment leads to excessive first cost, inefficient operation, and increased emissions. There are software packages that calculate an accurate heat loss value based on the detailed construction of the building. An example is Elite Software’s RHVAC program. DECTRA CORPORATION can run an in-depth heat loss analysis for a fee.

To learn more about Elite Software RHVAC or to purchase a software license visit: http://www.elitesoft.com/

COMMERCIAL HEAT LOSS: Calculating the heat loss for commercial buildings can be more complicated than for residential structures because the building type and application vary significantly. The easiest way to get a handle on heat loss figures for a commercial facility is to use a computer software package. A good commercial heat loss packages is Elitie Software’s CHVAC program.

To learn more about Elite Software CHVAC or to purchase a software license visit: http://www.elitesoft.com/

RESIDENTIAL HEAT LOSS EXCLUDING VENTILATION:

Old/Poorly Insulated House Uninsulated basement

Newer House Insulated Basement

Energy Efficient House Insulated Basement

Above Grade Floor Area (BTUH/sq. ft.) Below Grade Floor Area (BTUH/sq. ft.)

25 to 35

13 to 24

8 to 15

18 to 30

10 to 20

8 to 12

RESIDENTIAL VENTILATION:

 In newer, tighter energy efficient houses, mechanical ventilation is required at a generally accepted rate of 15 cfm per person. The following should be added to the heat loss for newer houses, but not added to the heat loss of older houses (unless the older house has been reinsulated and tightly sealed against air leakage).

Heat Recovery Ventilator Not Used Heat Recovery Ventilator Used 6,000 BTUH/person 3,000 BTUH/person

For more information on HRV products visit: http://www.vanee-ventilation.com/ http://residential.fantech.net/

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

RESIDENTIAL DOMESTIC WATER HEATING:

 Maximum delivered water temperature must be 120°F or less. An anti-scald valve is required by most codes on the discharge of the water heater. Maintain the water heater at 140°F or higher to kill bacteria and virus.

Normal Family of 4, Modest Size House Larger Family in Larger House 40,000 BTUH recovery rate 75,000 BTUH recovery rate 50 to 75 gallon water heater 100 to 120 gallon water heater

HOT TUB HEATING:

 Small (7’ to 10’ square x 4’ deep) insulated outdoor ho t tubes with an insulated cover generally require only 2,000 to 2,500 BTUH to maintain temperature when the tub is covered at outdoor temperatures of – 20°F. It is assumed that the hot tub is used for brief periods (say 1 to 2 hours per day) during which time the evaporative cooling of the water’s surface is the primary heat loss and may equal 6,000 to 9,000 BTUH. Any heat exchanger used to heat a hot tub should be sized for this larger value.

RADIANT FLOOR HEATING:

 Normal temperature drop is 10°F to 20°F per tube length.  Try not to exceed a floor surface temperature of 85°F (comfort and finish materials limitations).  Always insulate beneath a radiant floor system whether on or above grade. 2” of blue, pink, green or yellow board (not white bead board or polyurethane) is strongly recommend for slab on grade concrete slabs and R13 is the minimum recommended for upper level wood floors.

Maximum Length of Individual Tube Run

Typical Maximum Number of Tubes per Manifold

Maximum Flow

1/2” PEX Tubing 5/8” PEX Tubing

0.575 gpm

300 ft 450 ft

1 gpm

GARN® recommends the use of oxygen-barried, PEX-a tubing. For more information visit: www.mrpexsystems.com www.uponor-usa.com www.comfortprosystems.com

OXYGEN-BARRIED PEX-A TUBING IS NECESSARY IN ORDER TO MINIMIZE THE POTENTIAL FOR CORROSION.

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

FORCED AIR HEATING:

DO NOT MOUNT A HOT WATER COIL ON THE RETURN SIDE OF THE FURNACE. Warm air will be flowing over the blower motor and may not provide sufficient

motor cooling. Doing so will void the furnace warrantee and the UL listing of the furnace.

DO NOT MOUNT A HOT WATER COIL IN SYSTEMS SERVED BY A HIGH EFFICIENCY CONDENSING FURNACE. Doing so will void the furnace warrantee and the UL

listing of the furnace and create the potential for flue damage and a building fire.

 Size a coil that increases the air-side pressure drop by only 0 .25” to 0 .33” WC. Increase blower RPM to offset this increased static pressure and maintain CFM. Select a coil that will provide a supply air temperature of 110°F or slightly greater. Code limit is 140°F.  Pipe all coils in a counter flow pattern. The “normal” range of water tempe rature drop through a coil is 8°F to 20°F.  Mount hot water coils (flat and A-type) on the discharge side of the furnace. In almost all cases the coil will be physically larger than the existing supply air plenum. The plenum size will have to be increased. Sheet metal work must be designed and fabricated in accordance with SMACNA guidelines.  If the furnace is more than 12 years old, consider installing a new unitized fan coil unit that provides a motorized fan, filter, hot water heating coil, DX cooling coil and controls all within one insulated sheet metal unit. Such units are manufactured to replace an existing residential furnace and reasonably match the existing furnace’s overall dimensions . When selecting a unit, make sure to apply a correction factor (if necessary) for the hot water coil output at the entering water temperature (EWT) expected in the new system versus the EWT at the manufacturer’s rated output (see water temperature table in the Hot Water Baseboard Heating section of this manual).

For more information on unitized fan coil units visit: http://www.firstco.com/ http://www.magicaire.com

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

HOT WATER BASEBOARD HEATING:

 HWBB output ratings are based on 1 gpm to 4 gpm flow rate and an EWT of 215°F for most ¾” and 1” standard sizes. The following correction factors are to be applied to the 215 °F ratings when a lower EWT is used:

Water Temperature Correction Factors (entering air temperature = 65°F)

100 110 120 130 140 150 160 170 180 190 200 210 215 0.13 0.19 0.25 0.31 0.38 0.45 0.53 0.61 0.69 0.78 0.86 0.95 1.00

Supply Water Temperature (°F)

Correction Factor

EXAMPLE: The above table can also be used with baseboard rated at an EWT different 215°F. For example, if an EWT of 140°F is to be used, and the baseboard manufactured rated its baseboard at a an EWT of 180°F, then the appropriate correction factor is:

 Normal temperature drop is 10°F to 20°F per HWBB run. GARN® equipment and many non- wood systems today are based on an EWT of 140°F and a RWT of 120°F to take advantage of condensing boilers.  Combining a radiant floor manifold and PEX tubing with HWBB, can yield individual room control with a wall mounted, night set back thermostats.  Modern European flat panel wall mounted steel radiators are similar in flow requirements as HWBB.

For more information on HWBB products visit: www.sterlingheat.com

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

GLYCOL CORRECTION FACTORS AND FREEZE PROTECTION TABLES:

PROPYLENE GLYCOL FREEZE AND BURST PROTECTION

PROPYLENE GLYCOL HEAT AND FLOW CORRECTION

PROPYLENE GLYCOL PRESSURE DROP CORRECTION

Freeze Protection (% by volume)

Burst Protection (% by volume)

% By Volume

Heat Transfer

Pump Flow 1.013 1.022 1.032 1.045 1.059 1.077 1.096 1.120 1.145

% By Volume

140°F Solution

100°F Solution

Temp (°F)

20 10

18% 29% 36% 42% 46% 50% 54% 57% 60%

12% 20% 24% 28% 30% 33% 35% 35% 35%

20% 0.987 25% 0.978 30% 0.969 35% 0.957 40% 0.944 45% 0.928 50% 0.912 55% 0.893 60% 0.873

20% 1.067 25% 1.078 30% 1.089 35% 1.106 40% 1.122 45% 1.139 50% 1.156 55% 1.172 60% 1.189

1.098 1.120 1.141 1.168 1.196 1.228 1.261 1.293 1.326

-10 -20 -30 -40 -50 -60

NOTES: 1. GARN® recommends the use of Propylene glycol because it is not as toxic as Ethylene glycol. Check with the chemical manufacturer for specific concentration requirements. 2. The “Heat Transfer” correction factors represent the decrease in heat transfer when compared with 100% water and no change in flow rate. The “Pump Flow” correction factors represent the increase in flow required to maintain the same heat output rate as 100% water. 3. The “Pressure Drop” correction factors represent the increase in pressure drop of the system due to the glycol solution as compared to water at the same temperature. EXAMPLE: Select a propylene glycol solution for freeze protection of a coil designed for use as an outdoor air heating coil in Portland, ME. The ASHRAE design heating dry bulb temperature in Portland, ME is -1°F. By using the above table, a glycol solution of 36% is required for freeze protection. EXAMPLE: Let’s say, t he outdoor air coil in the previous example is rated for 50,000 BTUH at 140°F EWT, 20° Δ T, 5 GPM . What is the coil’s rated output with a 36% propylene glycol solution? What increase in GPM is required to maintain the 50,000 BTUH heat output rate? What increase in pressure drop will the pump see?

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

THE DIFFERENCE BETWEEN FREEZE AND BURST PROTECTION: (DOW CHEMICAL 1 )

Burst protection is required if your heating system/fluid will sit dormant at temperatures below freezing without being pumped, putting the pipes in danger of bursting. For these situations a slushy mixture is acceptable, because the fluid will not be pumped through the system. A slushy mixture is one that contains water and glycol, but as mixture of liquid and frozen ice crystals. Trying to pump fluid containing ice crystals can result in damage to system components. Since the mixture expands as it freezes, there must be enough volume available in the system to accommodate the expansion. Freeze protection is required if your heating system/fluid is going to be pumped at temperatures at or below the freezing point of the fluid. For example, systems that are dormant for much of the winter, but require start up during the cold weather, or systems that would be at risk if the power or pump failed. For these situations, the system must have enough glycol present to prevent any ice crystals from forming. It generally requires more glycol for freeze protection, keeping the fluid completely liquid, than it does for burst protection, where a slushy mixture is acceptable.

PUMP LAWS AND FAN LAWS:

Depending on the application, a pump or fan may need to be sped up or slowed down to achieve the desired function in a heating system. Use the following handy equations to calculate the increase or decrease in flowrate, pressure, and power consumption based on the original and the new pump or fan speed (RPM).

PUMPS

FANS

(

)

(

)

(

)

(

)

(

)

(

)

1 https://dow-answer.custhelp.com/app/answers/detail/a_id/5206/~/lttf---burst-protection-vs-freeze-protection- for-glycol-based-heat-transfer

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

D. PIPING AND PUMP SIZING

Correctly sized piping and pumps are necessary for the efficient and safe transport of heated water from the GARN® WHS unit to the building heating system.

All piping, pumps, wiring and controls, etc must be sized and installed by a qualified and licensed professional. All items are to be installed in full compliance with all national, state and local codes. For installations not covered in this

manual contact your local GARN® dealer for design assistance.

PIPING DESIGN AND CALULCATION GUIDELINES

Size all above grade and underground piping per standard industry guidelines:  Maximum head loss of 4’ to 6’ per 100’ of pipe for energy conservation.  Maximum velocity of 8’ per second to minimize surface erosion potential in most pipes.  Maximum velocity of 6’ per second to limit noise. Incorrect pipe sizing will adversely affect the heating system performance, efficiency and cost of operation. Undersized piping may cost less to install, but the pump size must be increased, adding significantly to the pump cost and the cost of operation. Head loss data for a specific pipe or tubing, and for various fittings is tabulated in manufacturer literature, plumbing manuals, state plumbing codes and local building codes. A representative sample of the head loss associated with various fittings for copper or steel is listed below. Recommended flow rates for various pipe materials are tabulated on the next two pages. EQUIVALENT FEET OF PIPE FOR SCREWED FITTINGS AND VALVES (for steel and copper) NOMINAL PIPE SIZE, INCHES 1/2 3/4 1 1 1/4 1 1/2 2

45 Degree Elbow, Regular 90 Degree Elbow, Long 90 Degree Elbow, Regular

0.8 2.2 3.6 0.7 0.3

0.9 2.3 4.4 0.9 0.4

1.3 2.7 5.2 1.0 0.5

1.7 3.2 6.6 1.5 0.7

2.1 3.4 7.4 1.8 0.8

2.7 3.6 8.5 2.3 1.0

Gate Valve, Open

Ball valve, Full Port, Open

Globe Valve, Open Tee-Branch Flow

22.0

24.0

29.0

37.0

42.0

54.0 12.0

4.2 1.7 5.0 8.0

5.3 2.4 6.6 8.8

6.6 3.2 7.7

8.7 4.6

9.9 5.6

Tee-Line Flow

7.7

Strainer

18.0 13.0

20.0 15.0

27.0 19.0

Swing Check Valve

11.0

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

EQUIVALENT FEET OF PIPE FOR PEX FITTINGS (brass fittings)

Nominal pipe size, inches

1/2

3/4

1 1/4

1 1/2

90 Degree Elbow

3.0 1.0 2.0 1.0

2.2 0.3 0.8 0.3

3.4 0.2 2.0 0.2

9.6 1.5 8.8 1.6

10.9

11.3

Coupling

2.7

1.4

Tee-Branch Flow

11.6

12.1

Tee-Line Flow

2.1

1.6

(EP fittings)

90 Degree Elbow

3.7 1.0 1.0 2.3

2.3 0.2 0.2 0.8

4.6 0.2 0.2 2.0

10.0

11.5

- - -

Coupling

Tee-Branch Flow

3.8 8.6

1.8

Tee-Line Flow

10.6

FLOW AND HEAT CAPACITY @ 4' OF HEAD LOSS PER 100' OF PIPE LENGTH

SIZE

INSIDE DIA.

FLOW, gpm

BTU/HR 10°F Δ T

BTU/HR 20°F Δ T

BTU/HR 30°F Δ T

Oxygen Barriered PEX Tubing

5/8” 3/4"

0.574” 0 .678” 0 .875” 1.280" 1.600" 2.030"

2.5

12,500 15,000 27,500 75,000 135,000 260,000

25,000 30,000 55,000 150,000 270,000 520,000

37,500 45,000 82,500 225,000 405,000 780,000

5.5

1 1/4" 1 1/2"

15 27 52

Type L Rigid Copper Tube - max. vel = 6'/sec for noise; max. vel = 10'/sec for erosion

3/4"

0.785" 1.025" 1.265" 1.505" 1.985"

3.5 6.5

17,500 32,500 60,000 90,000 195,000

35,000 65,000 120,000 180,000 390,000

52,000 97,000 180,000 270,000 585,000

1 1/4" 1 1/2"

12 18 39

Schedule 40 Black Steel Pipe

3/4"

0.824" 1.049" 1.380" 1.610" 2.067"

4.2

21,000 40,000 85,000 125,000 240,000

42,000 80,000 170,000 250,000 480,000

63,000 120,000 255,000 375,000 720,000

1 1/4" 1 1/2"

17 25 48

Hydronic System Design Manual ©DECTRA CORPORATION - March 2013

FLOW AND HEAT CAPACITY @ 6' OF HEAD LOSS PER 100' OF PIPE LENGTH

SIZE

INSIDE DIA.

FLOW, gpm

BTU/HR 20°F Δ T

BTU/HR 30°F Δ T

Oxygen Barriered PEX Tubing

5/8” 3/4"

0.574” 0.678" 0 .875” 1.280" 1.600" 2.030"

30,000 45,000 65,000 190,000 340,000 640,000

45,000 67,500 97,500 285,000 510,000 960,000

4.5 6.5

1 1/4" 1 1/2"

19 34 64

Type L Rigid Copper Tube - max. vel = 6'/sec for noise; max. vel = 10'/sec for erosion

3/4"

0.785" 1.025" 1.265" 1.505" 1.985"

4.2 8.5

42,000 85,000 120,000 230,000 480,000

63,000 127,000 180,000 345,000 720,000

1 1/4" 1 1/2"

15 23 48

Schedule 40 Black Steel Pipe

3/4"

0.824" 1.049" 1.380" 1.610" 2.067"

5.5 9.5

55,000 95,000 190,000 300,000 600,000

82,000 142,000 285,000 450,000 900,000

1 1/4" 1 1/2"

19 30 60

NOTE: Head loss for different GPMs than those listed in the flow and heat capacity tables can be ESTIMATED with the following formula:

(

)

For Example, let’s say we want to know the head loss of 3 gpm through ¾” Type L copper. Using the 6’ per 100’ table, the flow rate is 4.2 gpm:

(

) (

)

The above calculations could be approximated as 0.5’ per 100’ or 1’ per 100’ depending on the experience/discretion of the designer. The above formula is accurate for flow rates +/-20% of those listed.

For more information on PEX-a pressure drop data visit: ComfortPro Systems Document Center

PRESSURE LOSS CHARTS: STEEL, COPPER, PEX A summary of pressure loss data for piping comes from ASHRAE. The figures below show pressure (friction) loss for steel pipe, copper pipe, and plastic pipe. PEXa resembles plastic pipe, so the figures are generally accurate.

Reproduced from ASHRAE. (2009). Pipe Sizing. In Fundamentals (p. 22.7). Atlanta, GA

PIPING INSTALLATION AND HOOKUP GUIDELINES

 DO NOT install polybutylene or PVC plastic pipe.  Provide pipe support according to plumbing code guidelines.  After installation, flush all piping to remove, threading oil, solder flux, and debris.  All check valves and ball valves shall match pipe size. Ball valves shall be full port, if possible.  DO NOT install piping to produce a bull-head tee condition.

 Install accessible shut-off valves on the supply and return pipes near the GARN® WHS unit.  Install a separate boiler drain at the designated fitting on the front head of the GARN® WHS unit.  DO NOT Install automatic air bleeds in a GARN® or any non-pressurized system. Install only manual air bleeds at all system high points.  In new installations, provide a floor drain (with a hose bib if desired) to accommodate the overflow pipe and drain valve.  Install a domestic water sill cock for adding water near the GARN® WHS unit. A filter housing and filter should be mounted in series with, and adjacent to, the sill cock. Use a hose to fill the unit through the manway opening. DO NOT permanently connect the GARN® unit to a domestic water source.  Install drain valves in the distribution system where appropriate and required to allow future maintenance and equipment repair/replacement.  Insulate all above grade piping with ½” wall polyolefin pipe or 1” fiberglass insulation rated to 212°F (Thermocel, Imcolock, Imcoshield are preferred brands). PLUMBING WITH COPPER:  When installing copper distribution pipe use ONLY: long sweep elbows; 95-5 solder or brazing; and die-electric couplings where copper pipe joins steel pipe.  DO NOT CONNECT copper pipe directly to the GARN® unit; electrolytic corrosion will occur.  Install 4’ to 6’ of black steel pipe between the GARN® unit and any copper pipe. PLUMBING WITH STEEL:  Use 2” black steel pipe between the GARN® unit hot water supply connection and the inlet to the GARN® hot water supply pump.  If installing steel pipe, use ONLY black steel pipe. DO NOT USE galvanized pipe.

CALCULATION OF NET POSITIVE SUCTION HEAD FOR PUMPS

All GARN® wood heating units are zero pressure closed systems as opposed to:

 Open system – replaces the vast majority of its contained water daily. A good example of this is a domestic water heater.  Pressurized closed system – replaces little if any of its contained water on a yearly basis and operates with an internal pressure of 15 to 30 PSIG. A good example is a standard hot water boiler that is used for space heating. A zero pressure closed system does not develop internal pressure due to its unique open vent system. Such systems do replace a minor volume of contained water on a yearly basis. The designer must consider net positive suction head (NPSH) when selecting pumps for such systems. Proper selection will prevent cavitation and suction boiling that can: destroy the pump; prevent the system from attaining its rated heating capacity; or air lock the hydronic system totally. Graphs of pump performance and net positive suction head requirements are available from pump manufacturers. In all cases, the NPSHA available must be greater than the required NPSH for a specific pump. Generally, lower RPM pumps have lower NPSH requirements.

The net positive suction head available (NPSHA) is calculated:

NPSHA = AP + SP – HL - VP

AP = Job site atmospheric pressure, in feet of water SP = Static water pressure at the pump, in feet of water HL = Head loss between GARN® and pump inlet, in feet of water VP = Vapor pressure at desired HWS temperature, in feet of water

A simple equation for calculating the head loss between the GARN® and the inlet of the pump:

L = Length of pipe between the GARN® and the pump inlet EL = # of 45° and 90° elbows between the GARN® and the pump inlet BV = # of ball valves between the GARN® and the pump inlet GV = # of gate valves between the GARN® and the pump inlet T = # of tees between the GARN® and the pump inlet

HL, is the summation of pipe, fitting, and valve pressure losses between the GARN® unit and the inlet of the pump. All losses are to be calculated at maximum system design flow (GPM).

NPSHA must always be greater than the net positive suction head required (NPSHR) for the pump at design GPM, or cavitation and suction boiling will occur. The NPSHR is provided by the pump manufacturer (see the Pump Selection and Installation Guideline s section of this manual)

The following tables list atmospheric pressure (AP) at various elevations and vapor pressure (VP) at various HWS temperatures.

ATMOSPHERIC PRESSURE (AP)

Boiling Point of Water (°F)

Elevation (ft)

Atmospheric Pressure (ft)

Sea Level, 0

33.9 32.8 31.5 30.4 29.2 28.2 27.2 26.2

212 210 208 206 204 202 200 198

1000 2000 3000 4000 5000 6000 7000

VAPOR PRESSURE (VP)

HWS Temperature (°F)

Vapor Pressure (ft)

System Type Radiant Floor Radiant Floor Radiant Floor Radiant Floor

1.68 2.47

104 113 125 125 140 150

3.5

4.56 4.56 6.65 9.02

Air Coil

European Wall Radiator Hot Water Baseboard*

* Hot water baseboard can be sized to utilize 140°F HWS

UNDERGROUND PIPING:

Use only oxygen barriered, cross linked, high density polyethylene for underground installation. Pre- insulated PEX pipe manufactured by ComfortPro or Uponor is strongly recommended. Underground piping must be designed to allow for expansion and installed in strict compliance with the manufacturer’s specific instructions (such as the Microflex installation guide)

http://www.comfortprosystems.com/pdf/MFInstallGuide2009rev1web.pdf

 DO NOT install copper, steel, polybutylene or PVC pipe underground.  DO NOT join pipe underground unless absolutely necessary. If required use ONLY materials provided by the pipe manufacturer and installed according to their specific directions.  In very cold climates place a sheet of 2” thick x 24” to 48" wide foam insulation (blue, pink, yellow or green) board immediately above the pipe, centered on the pipe before back filling the trench. Trench depth in cold climates should be 4 feet (grade to top of pipe) if possible.  Deeper burial and additional insulation is required when below grade piping extends beneath a parking lot or roadway (frost will normally penetrate the soil to a greater depth in such areas).  Pressure test for water leaks before back filling the trench.  If the piping can only be positioned above frost depth, provide a pump timer to circulate water for five to ten minutes every hour during the heating season.  Avoid burial in continuously wet soils, under creeks, natural land depressions, drainage ponds, etc. DRY AREA BURIED PIPING DIAGRAM:  The following diagram shows how preinsulated, underground PEX-a piping shall be laid in dry areas.  Trench with a “ditch witch” to a de pth below the frost line.

MOIST AREA BURIED PIPING DIAGRAM:  The following diagram shows how preinsulated, underground PEX-a piping shall be laid in areas where moisture may sometimes be present.

ROADWAY AND PARKING LOT BURIED PIPING DIAGRAM:  The following diagram shows how preinsulated, underground PEX-a piping shall be laid in areas where snow is routinely cleared (such as below and paved surface where there is vehicle or foot traffic).

PUMP SELECTION AND INSTALLATION GUIDELINES:

All pumps must be selected based on a calculated total static and frictional head loss of the piping connected to the pump as well as the calculated required system flow.  Preferred pump brands include: Taco, Bell & Gossett, Wilo and Grundfos.  Select a pump that delivers a flow rate that does not violate the Piping Design and Calculation Guidelines (see previous section) for head loss and fluid velocity. Size the pump based on a calculated system head loss and system flow requirement – DO NOT guess.  All pumps shall be installed in strict compliance with manufacturer’s instructions, with particular attention to shaft orientation and the length of straight run of inlet and discharge pipe required to produce stated performance. In most cases, install pumps to discharge vertically up or horizontally.  Provide isolation full port ball valves flanges on the inlet and discharge of the pump.  Pumps should be located adjacent to the GARN® WHS unit if at all possible. Mount pumps at least 4 ’ below the surface of the GARN® WHS water level in order to prevent suction boiling at the pump inlet at higher water temperatures. (See previous section - Calculation of Net Positive Suction Head For Pumps)  A heating system may use several zones within a building. Likewise, one GARN® WHS unit may supply heat to several buildings. Use individual pumps with check values for each zone (or

building) and develop a common supply manifold to feed the pumps. Likewise, provide a common return manifold. DO NOT install manifold piping to produce a bull-headed tee condition.  In a remote location, zone pumps may be mounted adjacent to the heating system PROVIDED: the total head loss (static and frictional) of the supply pipe is equal to or less than 3 feet; and the pump is mounted at least 6’ below the surface of the GARN® WHS water level. Again, this is necessary to prevent suction boiling at the pump inlet. (See previous section - Calculation of Net Positive Suction Head For Pumps) .  DO NOT select a pump to operate near the top of its pump curve as “cycling flow” may occur with resultant damage to the pump and substandard system heating performance. See the figure below.

Area of good selection

 In an existing system, the pump size must be confirmed as adequate for the modified system.  Under-sizing a pump will significantly reduce the performance of the heating system and may allow system piping to freeze.  When hooking into an existing system, use a primary-secondary setup.

E. SYSTEM DISTRIBUTION CONNECTION AND SCHEMATICS Refer to the drawings on the next few pages for general schematics associated with a GARN® WHS unit heating a single building containing either a single zone system or a multiple zone system. The following drawings are schematics; as such it is neither detailed nor sufficiently complete for construction. Therefore, a comprehensive design must be completed by either an Engineer or Mechanical contractor who is knowledgeable about GARN® zero pressure heating equipment and the particular site conditions for which the schematic is proposed. This schematic is NOT a document of sufficient detail to yield a functioning heating system.

ZERO PRESSURE, FIXED TEMP - PRIMARY ONLY PUMPING:

A zero pressure, fixed temp system delivers a fixed water supply temperature to a non-pressurized hydronic heating system. Such a system is “ zero-pressure ” because the heating system is in direct contact with the atmosphere at the GARN unit. As the system heats up, the expansion of the water is reflected in the level of the GARN unit.

Advantages

Disadvantages

Simple.

 Cannot connect to a pressurized system.  If pumping to a level higher than the level of the GARN unit, the system will drain back to the GARN which could prevent many pipes from remaining “ wetted ” .

 

No expansion tank required.

 Constant speed or variable speed pump can be used.

ZERO PRESSURE, FIXED SUPPLY TEMP – PRIMARY SECONDARY PUMPING:

A primary-secondary pumping scenario involves two pumps: The primary pump circulates water between the GARN unit and the heat distribution piping; the secondary pump circulates water through the heat distribution piping.

Advantages

Disadvantages

 The main advantage of this type of system is that it can be directly connected to an existing zero pressure heating system.  Temperature and flow can be controlled independently.  Primary loop pump only needs to be sized from the primary loop piping.  Secondary loop pump only needs to be sized for secondary loop piping.  No mixing valve required.  No expansion tank required.

ZERO PRESSURE, MULTIPLE ZONE – PRIMARY SECONDARY PUMPING:

Another pump/piping strategy that can allow for a better control, smaller pumps and fewer design calculations is a “primary secondary pumping system” (refer to the drawing on the following page). This drawing details a single GARN® unit providing heat to two separate buildings, a home and a shop. Note the following:  Pumps P1 and P3 circulate water from the GARN® WHS unit to a pair of closely spaced tees within each building and then back to the GARN® WHS unit. The two pumps are sized based upon the head loss of the underground piping and the manifolds at the GARN® WHS unit. The head loss for the piping within either building is NOT taken into account. This makes for simpler piping head loss calculations when interfacing with an existing system.

The underground piping and the GARN® manifold are considered the “primary piping loop.”

 Pumps P2 and P4 simply circulate warm water (a mixture of cool system return water and hot supply water) to the heat delivery system in the building. The two pumps are sized based upon the piping and equipment head losses within the building without taking into account the head loss of the underground piping or the manifold at the GARN® WHS unit. This allows a good match between pumps P2 and P4 and the heat delivery equipment (air coil, hot water baseboard, radiant floor, or any combination thereof). In fact multiple small pumps may be used to split the building into independently controlled heating zones. Again, this makes for simpler piping head loss calculations when interfacing with an existing system because the existing pump generally does not have to be replaced as it experiences no net change in its resistance to flow.

The piping in the building is considered the “secondary piping loop.”

One could further increase the energy efficiency of this system by using variable speed pumps for P1 and P3. The speed of the pumps would be controlled by an optional temperature sensor or even an indoor-outdoor reset temperature controller. In this case, with the GARN® WHS unit hot (say 195°F) P1 and P2 would run slowly as only a small volume of hot GARN® WHS water would be required to warm the water within the secondary piping loop. When the GARN® WHS unit was cool (say 125°F) the pumps would provide a greater flow to warm the water within the secondary piping loop.

Some specifics about the closely spaced tees:

 The tees should be no more than 6 pipe diameters apart .  The tees should be located on the return side of any existing hot water heating system.  Flow between the tees may reverse direction when the secondary system pumps (P2 and P4) are activated.  The piping reducers are beyond the 12” of pipe and the two tees.  Activation of P1 and P3 may be interlocked with P2 and P4 except when there is a possibility of the underground piping freezing.

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