Instr. & Parts List 7052-1 Page 2
18. When the installation is complete, make sure that all valves in the oil line downstream of the Ratiotrol are closed. Remove the pipe plug from the bottom of the Ratiotrol, slowly open the oil supply valve, and run oil through the Ratiotrol into a suitable container to flush out any thread cuttings, scale, or dirt. OPERATION 1. The supply pressure to the Ratiotrol must be 25-30 psi. Pres- sures in excess of 30 psi tend to close the valve (ref. Fig. 2), and result in low outlet pressure. At 60 psi inlet, the oil flow will stop completely. Low inlet pressures result in high outlet pressures. 2. The outlet pressure of the 7052-01 Ratiotrol is 10 times the im- pulse pressure. i.e. 8 osi (½ psi) impulse: ½ psi × 10 = 5 psi. The outlet pressure of the 7052-0 Ratiotrol is 12 times the impulse pressure. i.e. 8 osi (½ psi) impulse: ½ psi × 12 = 6 psi. 3. Ratiotrols are factory adjusted for 1 psi outlet pressure with 0 impulse pressure. This may or may not provide an appropriate low fire oil flow for your application and may require readjust- ment as described in step 5 below.
7052-0
7052-01
Cap
Spring Cartridge
"K" Knurled Adjusting Nut
"L" Lock Nut
Air Diaphragm
Pressure
Air
Oil Pressure
Vent
Oil Diaphragm
oil fl ow
Valve Seat
Valve Plug
(center punch-- see below)
Figure 2. Cross section of Ratiotrols.
SERVICING E xcessive outlet pressure at low fire may be caused by: • Dirt or scale lodged in the Ratiotrol valve. If the dirt cannot be flushed out, clean the valve plug and seat by removing the plug in the bottom of the Ratiotrol and unscrewing the valve with a screwdriver. When replacing the valve, it must be re-seated by pushing it against the valve seat with a center punch, and tapping lightly.
4. After lighting the burner, drive the main air valve to high fire, and set high fire oil flow with the Sensitrol valve.
5. Drive the main air valve to low fire, and adjust low fire oil flow by using the spring in the Ratiotrol, as noted below (ref. Figure 2). 7052-01: Remove the spring cartridge cap. The preset condition of 1 psig outlet pressure typically entails location of the top of the adjusting screw at a level approximately 3/8" below the top of the adjusting nut. Ensure that this condition exists before proceeding further. Readjust to this level, if needed. Should additional adjustment of this assembly be required, turn the knurled adjusting nut clockwise for a lower outlet pressure and counterclockwise for a higher outlet pressure. DO NOT turn the adjusting nut more than ten (10) counterclockwise turns beyond the preset condition noted. Additional turns in this direction could result in separation of the extension spring/adjusting screw assembly from the adjusting nut. Replace the cap. 7052-0: Loosen the lock nut "L". Turn the stem clockwise for a higher outlet pressure, and counterclockwise for a lower outlet pressure. Tighten lock nut.
• Insufficient oil supply pressure. • Incorrect spring adjustment.
Insufficient outlet pressure at low fire may be caused by: • Excessive oil supply pressure. • Incorrect spring adjustment. Insufficient outlet pressure at high fire may be caused by: • Low oil supply pressure. • Plugged oil supply filter. • Plugged or leaking impulse line. • Ruptured air diaphragm. • Sensitrol™ valve not opened enough.
Erratic outlet pressure may be caused by: • Dirt or scale in the valve seat. • Plugged vent in the lower diaphragm housing.
6. Repeat steps 4 and 5 as necessary.
Oil leaking from the Ratiotrol vent indicates a ruptured oil diaphragm .
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