Operating instructions
48
Screen Display Explanation
Go to Page For 
Troubleshooting 
Control has blocking error for more than 20 
hours in a row.
Go to Page 50
Three unsuccessful ignition attempts in a row Go to Page 51
Open gas valve power circuit. May involve 
high temperature switch, gas valve, or gas 
valve relay in control module.
Go to Page 50
Safety Circuit is open. Go to Page 52
Blower speed does not reach speed calculated 
by Control Module.
Go to Page 53
Control Module internal error.
Replace Control 
Module
High Temperature opens during normal 
operation.
Go to Page 54
Control Module detects ame after gas valve 
is closed more than 10 seconds.
Replace Gas Valve
Flame is detected before gas valve opens. Replace Gas Valve
Control module internal error.
Replace Control 
Module
Lost ame signal 3 times during one heat call. Go to Page 55
Control Module internal error.
Replace Control 
Module
Control Module internal error.
Replace Control 
Module
External voltage supplied to DHW T-T or CH 
T-T terminals. Eliminate voltage using dry 
contact relay.
-
Flame detected when gas valve is closed. Go to Page 55
3
Blocking Error
REFLO too LO
13 - TROUBLE SHOOTING










