Tjernlund UCRT Rooftop Inducer Universal Control (Version X.06) 8504162 Rev A 05/11 - Manual (Page 13)

PSA-1 FAN PROVING SWITCH ADJUSTMENT
NOTE: This section is also repeated in the Rooftop Inducer instruction manual.
1. Drill an appliance 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. For most oil burners
sample over-fire draft. Connect draft gauge to sampling hole,
(See Diagram A).
2. For installations with a barometric draft control: Adjust weight on
draft control to minimum or most responsive position (Less Draft).
3. WARNING: This step requires that the wires connected to
the PSA-1 Fan Prover terminals be temporarily removed
and jumpered together. Disconnect power before proceeding.
Remove power source and connect leads attached to the C (com-
mon) and N/O (normally open) terminals of the PSA-1 together.
Attach a continuity tester to the C and N/O terminals of the PSA-1
Switch. Turn the PSA-1 adjustment screw counter clockwise until it
seats against the stop. The PSA-1 must be reconnected to the
interlocked heater(s) per the appropriate wiring diagram after
completing these procedures. Failure to do so may result in a hazardous condition such as an explosion, fire or carbon
monoxide poisoning resulting in property damage, personal injury or death. The UC1 interlock control number 9 dip switch
should be up or “ON” so the Pre-Cycle Prover Status check is deactivated.
Close all access doors and openings to the mechanical room that would typically be closed during heating equipment operation.
Fire all other heating equipment not connected to this vent system and operate exhaust fans or air consuming devices within the
facility that could affect the air pressure of the mechanical room.
4. Activate Rooftop Inducer and adjust balancing baffle(s) or speed control so that (-0.08" W.C. or -20 Pa) is read at the appliance
draft sampling position(s) referenced in Step 1. The PSA-1 switch contacts should close. If switch contacts do not close move
pressure sampling probe closer to the Inducer. Do not move sampling probe between manual damper and Inducer inlet.
5. Activate burner(s) at full capacity. Gradually adjust balancing baffle(s) or speed control to maintain a slight negative draft
(-0.02" to -0.05" W.C. or -5 to -12.5 Pa) at the heater’s draft sampling location(s). Allow vent temperatures to reach steady
state by referencing breaching flue gas temperatures.
6 Once flue gas temperatures have stabilized, verify that balancing baffle(s) or speed control are adjusted so that a slight nega-
tive draft (-0.02" to -0.05" W.C or -5 to -12.5 PA) is measured at draft sampling location(s). Individual appliance vent connec-
tions may require balancing baffles to evenly regulate draft.
7. Adjust balancing baffle(s) or speed control so that a slight positive draft (neutral to +0.01" W.C. or +2.5 Pa) is measured at the
appliance draft sampling location. Flue gases should just start to spill from the draft hood/draft diverter or barometric draft control.
8. Turn the PSA-1 Fan Prover Switch adjustment screw clockwise in 1/6-turn increments, waiting 2-3 seconds after each adjust
ment until the pressure switch opens and no continuity is read. Shut off heater for 5 minutes while continuing to allow Inducer
to operate.
9. Fire heater and readjust the balancing baffle(s) or speed control so that a negative draft (-0.02 to -0.05" W.C. or -5 to -12.5 Pa )
is once again measured at the appliance draft sampling location. This readjustment must be enough to cause the PSA-1 Fan
Prover Switch to close. The PSA-1 may take a few moments to close after each adjustment.
10. Confirm Fan Prover Switch set point by adjusting balancing baffle(s) or speed control so that a slight positive draft (neutral to
+0.01" W.C. or +2.5 Pa) is measured at the appliance draft sampling location. Flue gases should just start to spill from the
draft hood/draft diverter or barometric draft control and the Fan Prover Switch should open. Readjust the balancing baffle(s) or
speed control so that a negative draft (-0.02 to -0.05" W.C. or -5 to -12.5 Pa) is once again measured at the appliance draft
sampling location. Verify that the PSA-1 Fan Prover Switch closes.
11. IMPORTANT: Reconnect PSA-1 Fan Prover leads to switch that were jumpered together in Step # 3. Run entire heating/vent
system through 3 cycles to verify proper burner light off and operation. Verify that each appliance lights off properly with all
other appliances not firing. If barometric draft control(s) are excessively open, adjust weight so the
draft control damper opens less and repeat process starting with Step # 3.
12. Use a permanent marker or sticker to make a mark on speed control faceplate where final adjustment
was, (See Diagram B).
13. Sign and date these instructions to verify that the PSA-1 Fan Prover interlock was completed.
These instructions must remain on site. SIGN:_____________________ DATE :___________
COMBUSTION AIR
Adequate combustion air is vital for proper combustion and for safe venting. Likewise, for proper Inducer performance, adequate
combustion air must be available to the appliance. Many installers assume adequate combustion air is present, especially in older
structures. In some cases this is a false assumption, because many structures have been made "tight" due to weatherization. Size
12
DIAGRAM B
PLACE A MARK ON
SPEED CONTROL
FINAL SETTING
FIGURE 8052070
TJERNLUND ROOFTOP
DRAFT INDUCER
(MUST BE MOUNTED
SIX FEET OF SENSING
VERTICALLY WITHIN
FAN PROVING SWITCH
LOCATION)
APPLIANCE
GAS APPLIANCE DRAFT
SAMPLE LOCATION
FLAME RETENTION
OIL BURNERS
OVER-FIRE DRAFT
DRAFT CONTROL
/ DRAFT HOOD
TJERNLUND ABD-SERIES
BALANCING BAFFLE
(IF BAFFLE IS INSTALLED
IT MUST BE POSITIONED
AFTER FAN PROVING SWITCH)
DIAGRAM A