Tjernlund UC1 Universal Control (Version X.06) 8504107 Rev D 07/05 User Manual
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LED STATUS INDICATORS
LED #4 & #5 (Red) Flashing Alternately
= Venter in Pre-purge. (Pre-Purge options 0, 5, 20, 35 seconds)
LED #4 & #5 (Red) Flashing in Unison
= Venter in Post-Purge. (Post-Purge options 0, 30 seconds or 1, 2, 4, 8, 16 minutes)
LED #4 Flashes Continuously*
= Fan Prover opened for more than 10 seconds during burner cycle.
(Venter will run for 10 minutes, attempting to make Fan Prover)
LED #5 (Red) Flashing Intermittently
= With no call for heat, flashes 3 seconds on / 3 seconds off if microcontroller is working properly.
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.
CHECKING MEMORY FOR LAST FAULT CODE
IMPORTANT: Prior to accessing the fault code memory, note the settings of the dip switches so that they can be returned to their original Pre /
Post-Purge positions. When power is supplied to the UC1 use caution when moving dip switches.
The last fault code can be retrieved at any time by setting all dip switches 1-8 to the up, or “on” position. The last fault code, or lack there of, will
be indicated by counting the number of times LED 4 flashes. By moving any of the dip switches back to their original position, the fault code will
be cleared. NOTE: The UC1 board must have its 115 VAC power supply present when any of the (1-8) dip switches are moved back to their
original position for the fault code to clear.
IMPORTANT: Fault codes will automatically be displayed after a fault condition occurs. If the call for heat interlock signal
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.