No propane to heater

[tanksjeep]

I have a Laars LT400P heater and when I turn it on, the fan comes on, then I can see the igniter glowing but the heater never fires up. I checked the voltage to the valve and it is getting 28 volts (should be 24). If the igniter is glowing, should all the other safety switches be satisfied and then the valve should open? Or are there other checks (safety) that I need to look at?

 

[JamesW]

Is there enough propane in the tank?

Are all of the gas valves from the tank to the heater on?

 

[tanksjeep]

Yes on both questions.

 

[ps0303]

You need to check for gas flow at the heater. So check for gas flow before the regulator and then flow between the regulator and the heater. If you have gas in those places, then you need to see if you have gas flow on the manifold side of the heater.

 

[tanksjeep]

I did disconnect the gas pipe at the coupling that is just before the valve and after the shutoff and regulator. I didn’t measure it but gas was flowing pretty good. When the call for heat sends 24v to the valve, there is no gas to the manifold.

 

[homegameroom]

Some newer pressure regulators have safety valves in them that shut off the outgoing gas supply if it thinks the line is wide open. Maybe yours is like that, since it sounds like everything is fine but no flow?

 

[tanksjeep]

It’s flowing after the regulator just not after the valve.

 

[Bama Rambler]

Sounds like the gas valve isn't opening. You may need to replace the valve.
Gently tap the gas valve with the handle of a screwdriver while it's trying to fire.

Did you look at the inlet screen of the valve when you had the line disconnected?

 

[tanksjeep]

No I didn't. Where I disconnected the coupler, is about 6" from the valve on a straight section of pipe just before the 90 deg (Elbow) that goes into the heater and then into the valve. It looks like I need to remove the pipe on the inlet of the valve then remove the valve from the manifold.