Teledyne-Laars Boiler Ignition Problems

Boatster

Our 1898 Victorian has a gas-fired Teledyne-Laars Mini-Therm hydronic boiler (Model JVS-225H), installed in the mid 1980s and heating 19 radiators on three floors. Recently, it has been failing to cycle on at least 10 times a month, regardless of the outside temperature, and I have to reset it. The diagnostic code on the White-Rodgers ignition control module (Model 50D50-843) is always the same: False Flame. I’ve had technicians from several companies come try and fix it, but no luck. They all want me to replace the boiler, which I’m unlikely to do short of a cracked heat exchanger. I thought maybe someone here has a hunch about what’s going on. The one time it seemed to last longer between resets is when I set the pressure in the system a bit higher (26PSI vs. 20 PSI). Not sure that has anything to do with it, but thought I would mention it. Should I try replacing the ignition control unit? Other ideas? Theories? Fixes?

EBEBRATT-Ed

What type of ignition system does it have? Direct spark?, Hot surface etc.?

109A_5

Hello Boatster,

To me "False flame signal" means the Ignition Control Module is detecting the presence of a flame when there should not be a flame. In your case I presume there is no flame when the flame is not actually desired, however you should verify this, since an intermittently leaking gas valve or the Ignition Control Module may not be shutting off the gas properly. The Ignition Control Module also controls the power to the gas valve.

Assuming the error happens and it is not caused by a flame at the wrong time, the High Voltage Spark circuit is probably compromised somewhere. I would closely inspect the whole spark circuit (highlighted in Red below), no chafed, baked, discolored or otherwise compromised wires, the insulator at the flame sensor is not cracked or contaminated or otherwise compromised. The Ignition Control Module itself could be contaminated or failing if nothing else is found.

Even if you replaced the whole spark circuit and the Ignition Control Module I bet it would be much less than a whole new boiler.

EBEBRATT-Ed

Here is the manual. It has spark ignition. If your getting a "false flame" I would suspect a leaking gas valve the control is telling you it is sensing a flame when there should be no flame.

Laars-JVS225NDIS-Install-Instructions.pdf

White Rodgers-50D50U-843-Install.pdf

Boatster

@EBEBRATT-Ed and @109A_5 thank you so much! Sounds like replacing the ICM and spark circuit is my best bet, although I'll do a visual inspection first to try and verify the cause. Really appreciate your insights on this — especially taking the time to explain the context and the 'why' parts. I am better informed now, thanks to you.

Boatster