Tjernlund UC1 Universal Control (Version X.06) 8504107 Rev D 07/05 User Manual
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LED FAULT INDICATORS
Fault conditions are indicated by counting the number of times LED #4 (Red) flashes.
LED #4 Flashes 2 Times
Fan Prover was in electrically closed position prior to venter operation.
LED #4 Flashes 3 Times*
Fan Prover does not close within 60 seconds after call for heat.
LED #4 Flashes 4 Times*
Fan Prover did not re-close after 10 minutes of Venter operation.
LED #4 Flashes 5 Times*
Fan Prover opened for more than 10 seconds during burner cycle but closed within 10 minutes.
* Investigate cause of Fan Prover short cycling such as; Firing burner at capacities or temperatures exceeding Venter limits,
excessive vent pipe runs, elbows directly on venter discharge, high winds, plugged / kinked Fan Prover sensing tube or a faulty
Fan Prover switch. In-Forcer model’s intake screen and prefilter, if applicable, should be cleaned if necessary.
SYMPTOM 1: VENTER OPERATES CONTINUOUSLY
Verify that Venter is not in post-purge mode which could last up to 16 minutes. A factory post-purge has been set for 2 minutes.
LED #4 & #5 (Red) will flash in unison during post-purge. A Venter pre-purge could also be set for up to 35 seconds. LED #4 &
#5 (Red) will flash alternately during pre-purge. See “Pre / Post-Purge Settings” on page 3.
Verify that LED #1 (Amber) is not lit.
Yes, LED #1 (Amber) is lit: Check interlock wiring. Confirm burner control(s) are functioning properly. UC1 control is receiving
constant call for heat signal.
LED #1 (Amber) is not lit: Replace UC1 circuit board part number 950-8804.
SYMPTOM 2: VENTER MOTOR DOES NOT OPERATE
Verify that UC1 control has power, LED #6 (Red) should be lit. Verify that LED# 4 (Red) is not flashing. See “LED Status & Fault
Indicators” on page 12 if flashing. Verify RED voltage selection jumper corresponds with interlock voltage (i.e 24V, 115V or “Dry”).
No: Check circuit breaker, disconnect switches and wiring. Confirm that Venter leads are connected to N & MTR terminals.
Yes, LED #6 (Red) is lit: Verify that the interlocked burner is calling for heat, LED #1 (Amber) should be lit.
No, LED #1 (Amber) is not lit: Verify interlock wiring and that thermostat/aquastat is adjusted to call for heat. Verify that the RED
voltage selection jumper is installed so that it matches the voltage of the interlocked burner.
Yes, LED #1 (Amber) is lit: Verify Prover safety circuit fault does not exist. See, “LED Status & Fault Indicators” on page 12.
If faults exist check Prover P1 & P2 safety circuit.
If no faults exist, check for 115 VAC across terminals N and MTR.
Voltage present: Confirm Black and White leads from UC1 whip are securely fastened to Venter motor leads. If so, replace
Venter motor.
No voltage present: Replace UC1 circuit board part number 950-8804.
SYMPTOM 3: VENTER OPERATES, BUT BURNER DOES NOT
For SideShot SS1 and SS2 Series reset High Limit and see if burner fires. If High Limit was tripped, investigate the cause of high
heat. For any newly established call for heat the Venter will run for 60 seconds to try to close the fan prover circuit (P1 to P2). If
circuit can not be made within 60 seconds LED #4 (Red) will flash 3 times, indicating a prover check circuit fault on UC1 start up.
NOTE: The UC1 safety circuit and LED #4 (Red) will be reset if the call for heat interlock signal or 115 VAC power is removed. If
the fan prover makes on start up, but breaks for more than 10 seconds during the burner cycle, LED #4 will flash continuously indi-
cating a prover circuit fault. The Venter will continue to run for 10 minutes to try to make the prover circuit as long as a call for heat
exists. If Prover does not make within 10 minutes, the UC1 will shut down and LED #4 (Red) will flash 4 times indicating a prover
circuit fault. Remove the call for heat and then reestablish to reset the UC1 prover safety circuit (P1 to P2) & LED #4 (Red).
Verify that LED #2 (Blue) is lit.
Yes, LED #2 (Blue) is lit: Verify that "call jumper" is connected from J1 to J2 on UC1 circuit board if using typical wiring where sup-
ply voltage from terminal 1 is routed to terminal 3 through “call jumper” then to 4 when appliance interlock relay makes. With call
for heat established, verify that wiring is correct by measuring voltage between terminals 1 & 2 and 2 & 4 of UC1 terminal strip.
Voltage should be the same in both cases, if not rewire per appropriate diagram or confirm burner control(s) are functioning prop-
erly. NOTE: If a different voltage source is provided to terminal 3 which is switched to terminal 4 or when using the A-B dry con-
tacts, voltage measurements may not apply. For millivolt installations make sure system Limits are reset and relight pilot.
No, LED #2 (Blue) is not lit: Remove power from UC1 and push dip switch #9 up or “on” to deactivate Fan Prover status check.
Remove P1 and P2 prover leads off of Fan Prover switch and jumper together. Reestablish power and call for heat. After Venter
pre-purge, if set (up to 35 seconds), LED #2 (Blue) should light.
No, LED #2 (Blue) does not light: Replace UC1 circuit board, part number 950-8804.
Yes, LED #2 (Blue) lights up: The fan proving switch may not be closing, wiring connections are incorrect/broken or burner con-
trol(s) are not functioning properly. With Venter running, verify that Venter performance is sufficient to close Fan Prover contacts
by checking for continuity across switch. IMPORTANT: After continuity check push dip switch #9 back down to “activate” Pre-
Cycle Fan Prover status check unless using a SideShot SS1 Series or Draft Inducer with a PS1505 Fan Prover. Natural draft or
IMPORTANT: Fault codes will automatically be displayed after a fault condition occurs. If the call for heat interlock sig-
nal or 115 VAC power is removed, the UC1 board will reset and the fault will be stored in memory instead of displayed.
Any new fault will replace any previous fault.