Troubleshooting Guide: Fenwal Dsi - Schwank SET - SETU Owner's Manual

21. TROUBLESHOOTING GUIDE - FENWAL DSI
(also see Heater Troubleshooting next page)
SYMPTOM
1. Dead
2. Thermostat on
- no blower output
3. Pressure switch input okay,
but no Trial-for-Ignition
ter purge delay
4. Valve on, no spark
5. Spark on, no valve
6. Flame ok during TFI, no
flame sense (after TFI)
SET(U)-F / ITT(U)-F Manual
IM091221
RD: FEB 2014
RL: 8B
RECOMMENDED ACTION(S)
A. Miswired - check electrical supply (120Vac ± 5%)
B. Transformer bad (24Vac ± 10%)
C. Fuse/Circuit breaker bad
D. Bad control (check LED for steady on)
A. Miswired
B. Bad thermostat no voltage @ terminal W
C. Bad control (check LED for steady on)
A. Miswired (check PSW terminal voltage: 24Vac ± 10%)
B. Flame sense problem (existing flame: check LED - 2
af-
flashes)
C. Bad control (check line voltage between L1 & IND)
A. Shorted electrode
B. Open HV cable
C. Bad control
A. Valve coil open
B. Open valve wire
C. Bad control (check 24Vac voltage between V1 & V2)
A. Bad electrode
B. Bad HV igniter wire
C. Poor ground at burner
D. Poor flame (check flame current)
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