Hayward H400 Heater won't fire .

[dathornt]

Hello.

I am new to this forum and see that this thread and noticed that this is the same heater, so here i go. I have the Hayward H400 heater and I just can't get it to kick on....i installed a new board when a couple of resistor burned up and new pressure switch. When i start it up the fan kicks on, pilot light is nice and red, glowing through the window and then it clicks and the pilot light just goes out, then it tries again...always with the same result of no burn. i did have a technician come out but i honestly didn't trust that he did the right things...he said the natural gas valve needs to be replaced....i took off the valve, and performed a bench test....brought it into work and applied 24 volts to it and i could hear the valve opening and closing just fine....actually took the valve all apart and cleaned it and double check (not much to it). Any help you can provide would be appreciated ​

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[ps0303]

Is this the FD series unit? I would want to do a test to see if when the valve clicks, there is actually gas pressure on the manifold side of the valve and at the right pressure.

 

[Hayward Pool]

The fact that you are viewing the flame through the window tells me this is most likely a millivolt. Assuming this is a millivolt heater the first thing I would do is make sure all the gas orifices are clean of spider webs. If this does not solve the problem it sounds like a pilot generator. As per PS0303 I would need to know the exact model number of the heater to go further with diagnosis. This can be found inside the heater on the label on the floor or on the right side of the heater. As always you want to make sure you have a good contractor well versed in heaters. I always tell customers you can tell a good heater technician when he walks in the back yard with a gas manometer and volt meter. You can not tell if the gas valve is bad or Ok with out these tools.