Help with natural gas H150 heater

[pdc]

I hadn't used the Hayward H150 heater for 2 years. The pool has been open and running for about a week and all had been heating normally. I had someone spray a finish on the surrounding deck. The over spray got in the pool and clogged the DE filter which I dealt with. Seemingly about the same time the heater began heating only marginally. I'm not sure if the finish going through it is the problem or not.

The burners are clean and fully firing. I took the manifold off the heat exchanger and snaked the copper tubes to be sure there were no obstructions. The exchanger is clean and clear and in fine shape. The one fault I found was the bypass which looks like a car thermostat was inoperative, frozen in the shut position. I couldn't get one immediately so I put it back together without the bypass. It still does the same marginal heating. I'm going to get the new bypass but it doesn't seem to be the problem as it operates the same with the bypass closed or with the bypass not there.

I do have a diverter valve and I reduced the flow through the heater until it make knocking noises from steam and then added back enough flow to stop that and still same results.

So I'm stumped. What could cause a fully firing heater that has a clean as a whistle heat exchanger to only marginally heat? Days before the heater heated just fine with noticeably warm water coming through the return jet. It now produces water that is barely warmer then the pool water through the jet.

Any help would be much appreciated.

 

[ps0303]

How have you determined that the heater isn't heating optimally? What size pool do you have? Why not push more water thru the unit? When you bypass lots of water do not expect to feel warm water coming thru the returns as more is being bypassed than heated.

Well sound like you've done it all. Only possible thing I can think of is a low flame thus not optimally heating the water. If that isn't it I have no clue.

 

[pdc]

Thanks for that. I will look at the possibility of low flame tonight. It seems to be a pretty solid flame. What controls might cause the flame to fire but perhaps not fully? Also I did have more water through the system. Reducing it was just an experiment to see if the output pipe got warmer which it may have a little but of course with all the unheated water blended there was no net difference.

16x32 above ground oval. Four feet deep.

 

[ps0303]

Also check and clean the heat exchanger. Pop the top.

 

[pdc]

Thanks did that it's Sioux and span.

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[pdc]

Thanks did that it's spic and span.

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Sent from my SM-G928V using Tapatalk

 

[ps0303]

Any of the fins bent out of shape?

 

[pdc]

Nope

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[danpik]

let the heater run for a few hours and measure the water temp difference before and after. With about 95,000 Lbs of water and 150,000 BTU (120,000BTU output) you should see about 1 - 1.25 deg/hr of temp increase per hour. This is the only real way to see if the heater is outputting the rated amount.

 

[pdc]

It was heating at that rate (at least a degree per hour) when I first ran it. After the over-spray (might have been a significant amount) is seemingly when the significant reduction of heating occured. That's why I opened the heat exchanger and snaked the passages. they are very clear, no obstructions or goo in there.

 

[pdc]

I misspoke in my original description. It was the thermostat that was faulty that is now not installed (new one will be here Thursday). Amazon.com: Hayward HAXFCT1930 Flow Control Thermostat Replacement for Hayward H-Series Ed1 and Ed2 Style Pool Heaters: Patio, Lawn Garden

Could it be something to do with the bypass valve kit? Amazon.com: Hayward HAXBPK1932 By-Pass Valve Kit Replacement for Hayward H-Series Millivolt Electronic ED1 Style Pool Heater: Patio, Lawn Garden

 

[ps0303]

Yes you replaced the flow control thermostat. If the bypass is still solid and in good shape, makes no sense to replace it. Does the unit not have a digital display? If not I wouldn't spend too much money on it.

 

[pdc]

Yes you replaced the flow control thermostat. If the bypass is still solid and in good shape, makes no sense to replace it. Does the unit not have a digital display? If not I wouldn't spend too much money on it.

Would the flow control thermostat have this effect? Currently it is running with no flow control thermostat. I reassembled with it out until the new one gets here. No digital display.

 

[pdc]

If I remove what I think is the thermostat sensor, the copper probe with a hard wire that goes into a tube on the exchanger, will that cause the burner to stay on constantly.

 

[ps0303]

Yes it could and is not advisable.