DRAFT AND PSA-1 FAN PROVER ADJUSTMENT PROCEDURES
DRAFT ADJUSTMENT FOR MECHANICAL DRAFT INSTALLATIONS
IMPORTANT:
If installation includes a CPC-2 Controller, disregard these procedures and refer to the CPC-2 & System instructions for
draft and PSA-1 Fan Prover adjustment procedures.
Close all access doors and openings to the mechanical room that would typically be closed during the heating equipment operation.
Fire all other heating equipment not connected to this vent system and operate exhaust fans or air consuming devices within the facil-
ity that could affect the air pressure of the mechanical room.
1. Follow the heating equipment manufacturer’s instructions for sampling draft. In their absence drill a draft sampling hole in the vent
riser after each draft diverter or between the flue outlet and the draft hood / barometric draft control of each appliance.
2. It is important to note that various environmental and temperature conditions will cause draft levels to fluctuate. Set draft in the
middle of appliance manufacturer’s acceptable range.
3. For installations with a barometric draft control: Adjust weight on draft control to minimum or most responsive “open” position (Less
Draft). Turn adjustment screw on the PSA-1 counter-clockwise until it stops. Activate the VSUB Blower by installing a jumper be-
tween positions MS3 and MS4 on the VFD terminal strip. Adjust the speed control knob on the face of the VFD until approximately
-0.10" W.C. is measured at the draft sampling location referenced in step #1. If multiple heaters are being vented by a single VSUB
Blower, adjust balancing baffles so that approximately -0.10" W.C. is measured at each draft sampling location.
4. Remove jumper from MS3 and MS4 positions on VFD terminal strip. Activate burner farthest from the VSUB Blower at full capacity.
Adjust the draft within the manufacturer’s requirements by opening/closing the balancing baffle for that heater. Perform combustion
test and make any adjustments necessary to the burner so that it operates efficiently. If the desired draft cannot be maintained
through adjustment of the balancing baffle(s) adjust VSUB Blower speed to achieve desired draft range.
5. Fire each successive heater repeating the same procedure for each heater as outlined within step #3. Keep the previously adjusted
heaters operating as each successive heater’s draft is being adjusted.
6. After the draft has been adjusted for all heaters, and with all heaters operating, reverify that the draft on all heaters is within the
manufacturer’s specified range. Make any slight adjustments necessary to the balancing baffle, draft control or VSUB Blower speed
to allow all heaters to operate within the range specified. Record the final Hz _____ (speed) setting as referenced on the VFD
display.
SIDEWALL TERMINATIONS:
It is normal for the draft control damper to be nearly wide open. This will allow the VSUB Blower to
respond to high wind loads.
PSA-1 FAN PROVER SET POINT ADJUSTMENT FOR MECHANICAL DRAFT INSTALLATIONS
1. Activate all heaters at full fire for 5 minutes.
2. Reduce the VSUB Blower speed slowly to the point that a negative draft cannot be maintained or flue gas spillage is detected at
any of the heaters.
3. Turn PSA-1 adjustment screw clockwise in 1/4 turn steps waiting 30 seconds between each turn until the PSA-1 switch opens,
causing the heaters to be disrupted. Turn the PSA-1 adjustment screw 1/4 turn counter-clockwise and replace electrical box cover.
4. Increase the VSUB Blower speed back to its original setting that was recorded in step #6 above. Hz _____ (speed)
5. Cycle all heaters and verify proper light-off and operation. Return all non-connected heaters, exhaust fans and air consuming
devices to their previous condition.
PSA-1 FAN PROVER SET POINT ADJUSTMENT FOR COMBUSTION AIR INSTALLATIONS
IMPORTANT:
If installation includes a CPC-2 Controller, disregard these procedures and refer to the CPC-2 & System instructions for
draft and PSA-1 Fan Prover adjustment procedures.
Close all access doors and openings to the mechanical room that would typically be closed during the heating equipment operation.
Fire all other heating equipment not connected to this vent system and operate exhaust fans or air consuming devices within the facil-
ity that could affect the air pressure of the mechanical room.
1. Follow the heating equipment manufacturer’s instructions for sampling draft. In their absence drill a draft sampling hole in the vent
riser after each draft diverter or between the flue outlet and the draft hood / barometric draft control of each appliance.
2. Turn adjustment screw on the PSA-1 counter-clockwise until it stops. Turn the speed control knob on the face of the VFD complete-
ly clockwise (maximum Hz).
3. Activate all heating equipment within mechanical room at full fire and allow to reach steady state operation. Steady state operation
is achieved when flue gas temperatures stabilize.
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