26
Thermostat Control Model
Troubleshooting
d.
Check Thermostat: Connect lead to #5 on terminal block. If no voltage is read, turn up thermostat. If
voltage is still not present, replace thermostat (S3735100).
e.
Check Fenwal Control: Connect lead to L1 on Fenwal. If no voltage is read, check wire connections
between Fenwal Control and terminal block #5. Replace wire if needed.
f.
Check Solenoid: Connect lead to V1 on Fenwal. If no voltage is read, Fenwal board (S224190) may
need to be replaced.
g.
Check Fenwal Control N: Take a continuity test between L2 on Fenwal and N. Replace wire if
needed.
If Solenoid is not Energizing
•
Check Solenoid Voltage: Connect lead to V1 on Fenwal and N on terminal block. If voltage is not read,
replace solenoid (S224355).
Green Light is On, But No Spark (at some point Red Light will turn on)
•
Check Flame Rod wires for loose connections on burner assembly and inside control box (B, Gnd” and
“H.V.OUT on Fenwal Control).
•
Look for cracked porcelain on flame-sensing rod (S208916). Moisture in cracks can ground rod to
housing and eliminate the rods ability to sense flame. If cracked, replace.
Spark is Present, but No Flame
•
Check for gas flow at burner.
•
Check if heater gas shut off valve is open.
•
Check heater regulator to determine a gas flow is available.
•
Check solenoid voltage.
Burner Ignites, but Locks-Out in 10-20 Seconds
•
Look for cracked porcelain on flame-sensing rod (S208916). Moisture in cracks can ground rod to
housing and eliminate the rods ability to sense flame. If cracked, replace.
•
Check flame-sensing rod wire for grounding or weak connection. Follow wire from rod to control board
terminal “B,Gnd” and “H.V.OUT”. No grounding to housing should be found.
Burner Ignites and Operates, but Nuisance Lock Out Occurred
•
Replace flame-sensing rod (S208916).
•
Check flame-sensing rod wires and flame-sensing rod (S208916). Look for cracks or grounding in wires.
•
Check tank pressure, line, and strainer for blockage. Heater unit works best with a tank at 30% above
capacity.
•
Is there possible freeze-up of regulator? If so, allow heater to warm up.
