North American Air/Oil Ratiotrol ™
Instructions & Parts List 7052-1
5 pipe dia. minimum
3 pipe dia. minimum
INSTALLATION 1. Remove thread protectors from the inlet and outlet oil connections of the Ratiotrol, and from the tapped impulse/vent connections in both diaphragm housings. 2. Mount the Ratiotrol horizontally in the oil line, with the spring housing pointed straight up and the arrow on the body pointed in the direction of flow.
impulse line
air
spring adjustment
to burners
Air Control Valve
Air/Oil Ratiotrol
install tee for checking impulse pressure
vent
Expansion Chamber
Oil Strainer
3. Install pipe unions on both sides of the 7052-01 Ratiotrol for easy access. The 7052-0 Ratiotrol has integral unions.
to burners
oil at 25 to 30 psi
Gauges and Gauge Cocks
return line to circulating loop (heavy oil only)
Thermometer
4. The Ratiotrol discharge centerline must be kept as close to the burner centerline as possible. Under no condition may the dif- ference in their centerline elevations exceed 12".
Figure 1. Ratiotrol piping arrangement .
5. Multiple burners mounted on elevations more than 12" apart, require a Ratiotrol on each level.
13. Ratiotrol operation depends on impulse pressure from the combustion air line. The impulse line connection must be located at least (5) pipe diameters downstream of the main air control valve or any fittings (elbows, tees, etc.), and (3) diameters up- stream of any valves or fittings. The connection must be located on the same axis as the valve shaft, but not on the bottom of the pipe. 14. The combustion air impulse connection is made by welding a 3⁄8 " half coupling onto the air pipe, and drilling a 3⁄8 " hole through the pipe. Remove all burrs from the inside of the pipe. 15. Connect the ¼" impulse tap, on the upper diaphragm case of the Ratiotrol, to the 3⁄8 " connection on the main air line, using 3⁄8 " copper tubing (or pipe if desired). Installing a ¼" tee in the impulse tap connection provides a convenient location for installing a pressure gauge. 16. Install a 0-60 psi pressure gauge with isolating gauge cock on the upstream side of the Ratiotrol, a 0-30 psi gauge with isolat- ing gauge cock on the downstream side, and a 0-32 osi gauge in the impulse connection. 17. If the combustion chamber pressure is greater than ±½"wc, connect the ¼" t ap on the lower diaphragm housing to the combustion chamber with 3⁄8 " tubing.
6. If the burner is fired vertically, the Ratiotrol discharge centerline must be on the same elevation as the burner backplate.
7. If burners are mounted on both sides of a furnace, install Ratio- trols on both sides. Do not install a Ratiotrol on one side only, and then cross over or under the furnace with the outlet piping. 8. The oil pipe from the Ratiotrol must enter the burner from below the centerline, to prevent dripping and afterburn occurring after the burner is shut off.
9. Each control zone requires a separate Ratiotrol.
10. Install tee's with valves in all high points of the oil line to permit bleeding entrapped air.
11. Install a 8553 Strainer in the oil line upstream of the Ratiotrol to prevent pipe scale, dirt, etc. from lodging in the Ratiotrol, Sensitrol™ valve, or atomizer. 12. Install an 8521-01 Expansion Chamber in the oil line downstream of the Ratiotrol to prevent damage from thermal expansion of the oil when a downstream oil valve is closed.
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