Teledyne Laars Lite won't stay lit

[bradharper1976]

I have an older laars lite pool heater with the hot surface ignition. The heater will ignite for a few seconds and then turn off. It will do this about 3 times then stop. I have checked all the sensors and get the proper 24 volts in the right places. The thermister also reads correctly.

With all the trouble shooting it is either the gas valve or the controller itself. The gas valve is a r0317100 and the controller is a r0317500. What I get on the brown wire coming from the valve output of the controller to the mv1 input on the gas valve is 24 volts for about 7 seconds after the ignitor gets hot then it goes to 0 volts. When the mv1 on the valve is getting the 24 volts gas is being released and the burners fire up until mv1 goes to 0 volts.

Reading the jandy troubleshooting guide for the laars lite2, which has pretty much the same components it says the mv1 should only have 24 volts on it for the 7 seconds at start up. This seems incorrect to me as wouldn't the gas valve need 24 volts constantly to keep the solonoids open? So I am unsure if the controller is messed up or is it the valve? I cannot find any info on the operation voltages for these wires.

Thanks for any help anyone can provide

 

[ps0303]

Sounds to me like the ignitor isn't sensing flame or if your unit has a separate flame sensor, it is not working.

 

[bradharper1976]

No flame sensor on this model. How can I tell if the ignitor is sensing flame? Is the controller sensing ohm changes in the ignitor?

 

[ps0303]

So the ignitor is the flame sensor. then I've never gotten into actually trying to determine if the ignitor is sending back a signal or not. It would stand to reason it would be looking for some ohm change, probably a steady reading as the flame is keeping the ignitor hot. I just usually swap out the sensor and see what happens. It's just easier for me to do that. If I swap that and it still won't stay lit, then I would suspect the control module.

There are only a few items I part swap like this in the field.