North American 4725 Radiant Tube Burners Control Requirements
Sheet 4725-4
4725- -E SPARK IGNITED BURNERS
WHEN & HOW
Type of Control 4725- -E
Minimum Operating
Maximum
HOW
WHEN should
Valve
Type of
Lighting
should gas
should
Control Motor Speed
Linkage Adjust-
Gas Shutoff Valve and
Air
Air
and spark be
spark be turned on
spark be
Burner
Pressure
Pressure
turned on
turned off †
ment
Opening Speed
Spark by manual push button. Burner
High-Low
held at low
Before or at same
Manually
or
0.1 to
Below
aft er
Not
Not
Manual
Modulating
0.2 osi
1 osi
Gas - by
time as
burner is
Critical
Critical
(not off)
Recommended
manual valve
gas
lighted
Either
By motor end switch or
a.7219- -SS
Motor end switch or
pressure
b. Conventional
switch before
30
Set for
b. Solenoid
On-Off
"
"
air
"
seconds
slow
b. Valve‡
pressure
reaching high fire
or
movement
c. Hydramotor‡ b.Fast Opening b.(10-20 sec)
switch
slower
at low
Modulating
"
"
"
"
By timer aft er 15 seconds
"
"
"
to off
† With some control systems the spark can be repowered as the motor starts from high to low. This is not objectionable as long as gas and spark go off simultaneously as motor approaches low end of travel.
‡ Automatic gas valve should be downstream of regulator for good lighting.
GENERAL NOTES: 1. Make certain that burner is at low before gas and spark are turned on.
2. Use a constant spark for ignition--a distributor will not work for direct spark ignition. 3. WARNING: Do not adjust burner for lean low fire--if done, burner damage may result. 4. Allow a 30-second delay between shutoff and relighting to avoid mis-operation. 5. When burning propane, use full primary air and set slightly lean.
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