Question about Hayward H2501 HSeries Millivolt Natural Gas Pool Heater 250000 BTU

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My Hayward gas heater H250 does not seem to be heating as hot as previously. Is this my imagination or can there possibly be a heating issue? It is set at max heat but does not seem to be as hot when it enters the pool even though it is definItely warm, just not very hot.

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  • skyle99 Nov 15, 2010

    This was very helpful. Thank you.



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There could be an issue with Hayward gas heater.

Have you tried resetting the high limit inside the heater service panel?

If you remove the service panel you should see a limit switch with a red reset button.

My Hayward gas heater H250 does not seem to be - taran_2005_4.jpg

It will look similar to this. If the high limit is tripped it will keep it from lighting.
Now there are other safeties involved. There are 3 more limit switches, (automatic reset) with no button on them, the pressure switch that proves there is enough water flow, the on/off switch and the thermostat that regulates the water temp.

If any one of these is not making a complete circuit it will keep the main gas from opening. You need to systematically check and see what is keeping it from working properly.

The most obvious places to check are the manual reset, then make sure your filters are clean for maximum water flow and make sure no bypass valves are preventing enough water flow.

The valve operates on 750 millivolts DC. (less than 1 volt.) A bad connection at any of these switches will prevent it from working properly.

You can take a little piece of wire and jumper the TH and TH/TP terminals on the gas valve momentarily to see if it will light. If it does, you know the pilot and valve are OK. If it doesn't you need to go through one by one and test each safety switch to see what is holding it from working. A volt meter comes in hand here.

If you are not comfortable working with any of this..I would advise getting your service guy back out there.

Let me know,if needed further assistance.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

Posted on Nov 14, 2010


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