49
EQM Control Model
Troubleshooting
o
Check 24vdc power supply: Connect lead to V+ on power supply. If no voltage is read, Power
Supply (S224457) may need to be replaced.
o
Check EQM: Connect lead to 24V on EQM. If no voltage is read, check wire connections
between 24vdc Power Supply and EQM. Replace wire if needed.
o
Check Mod Motor: Remove cover from Mod Motor.
Connect lead to “1 RD G.” If no voltage is read, Mod Motor (S224345) may need to be
replaced.
Connect lead to “3 GY Y” voltage will be between 0-10vdc. If no voltage is read, Mod
Motor (S224345) may need to be replaced.
o
Check EQM: Connect lead to “0-10V” voltage will be between 0-10vdc. If no voltage is read
EQM (S224343) may need to be replaced.
o
Check Temp/RH Sensors (repeat for second sensor): Connect lead to 24V on EQM Input Air or
Head Space. If no voltage is read EQM (S224343) may need to be replaced.
o
If above tests come back normal the EQM (S224343) or Temp/RH Sensor (S224225) may need
to be replaced.
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).
No Spark on Flame Rod
•
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.
