Hayward H200 heater problems

[ntobik]

Have a 2001 Hayward H200 heater that came with the house. It didn't work when we opened the pool, but since we'd lived here less than a year the warranty covered it. Received a new pilot generator assembly and gas valve.

I used the heater twice, the first time to warm the water from 74 to 84 to get the pool open. Then about a month later to bump it up a few degrees, it's been off since then.

I tried to fire it up a few times recently and the pilot light would shut off. My dad has some HVAC experience and mentioned the gas pressure was probably too low. Walked through the troubleshooting chart and slightly increased pressure and pilot stays lit.

Problem is the burner won't fire up.

I have a multimeter and started to mess with this thing. It's a millivolt system. I can fire up the pilot light and when I measure I can get 522 mV from the pilot generator. This is with the gas button pressed down. The second I let go and the button pops up mV drops down to the 200 range. I believe this is my issue because 200 mV isn't enough to open the gas valve to fire up the burner.

Any idea what's going on?

Question:
1) Should voltage drop once I stop pressing the pilot light button?
2) Even though voltage drops it's steady across the TH connections, meaning I think my wiring is good.
3) What voltage should this thing be at to get the gas valve open? Does it only need to be 500 mV initially?
4) Why would this have worked recently then stopped? Nothing changed except the pilot would shut itself off. Could that have caused damage somehow?

The company that "fixed" it by replacing the parts makes the term incompetent seem like a compliment. If I called them they'd charge me a usurious rate to look at their broken work.

The techs told me this thing was old, but the burners are good and the heat exchanger is good. So with a new pilot assembly and gas valve I should have a working heater in an old enclosure.

Thoughts?

 

[banditig]

I think the thermopile should stay around 500mv.
If its older unit with low pressure they tend to build up soot.

 

[ps0303]

How long ago did the new pilot generator get installed?

When the pilot button is let off and the pilot goes out, usually it does suggest that the thermopile is bad. You should also check the flame itself. Is it a nice strong looking blue flame?

I would consider maybe replacing the unit all together. Pilot systems still burn fuel even if you aren't using it as long as the pilot is lit. If you think you can turn the pilot off and on at will, as systems get older they become unreliable. Your H200 is probably at least 8-10 years old. Consider replacing it also to get rid of an old antiquated system that will probably be headaches down the road.

 

[ntobik]

Thanks for the replies, they are really helpful.

The pilot generator and gas valve were installed at the end of May. I need to figure out how to check the flame. The pilot isn't visible from the outside, I think I can rig up some mirrors and see inside the unit.

It makes sense the thermopile could be bad. At least that part is cheap.

In terms of the unit's age, it is at least 15 years old. I'm burning on fumes at this point, but I was hoping with the replacement parts that I could limp along another season or two.

 

[ps0303]

No way should you be having this issue if it was done this past May unless they used the original thermopile.

Just remember, you either pay now or you pay later. Either way it's going to cost you. However, how much will this unit cost you in between now and then.

Pools heaters have a life span of 7-10 years. You are way past that on your current unit.

 

[ntobik]

I'm sure they used the original thermopile, all they did was drop in the new pilot assembly and the gas valve. The thermopile looks easy enough to replace, I might try that next especially since it's a $40 part.

My wife just wants a new unit. I'd prefer to buy one in the spring when I can plumb it in before I open the pool. The nice thing is I have a conduit run to where the heater is so I can buy an electric ignition heater vs the millivolt one we have now.

In terms of reliability is there a brand that's more reliable or better than others?

 

[ntobik]

Ok, maybe I need to backtrack on the thermopile. It looks like the thermopile is part of the pilot assembly. I went out there and poked around and from what I can tell it looks like it's new wiring and was replaced as well.

I guess I'm at a loss with this. Could it be a bad wire in there somewhere? I can take a picture later today. Some of the wiring was replaced, others are old, maybe there's a short?

 

[ps0303]

OK lets take a step back. Make sure the on/off button on the front of the heater is off. Turn the temp all the way down to cold. Once you do that light the pilot and measure your millivolts coming out from the pilot. What is this reading? If 450+ you have a good strong pilot and the thermopile is good. Now switch on the on button. If the millivolts drop, then you have a bad safety somewhere drawing down the power. Sometimes even the on/off switch can draw down the power.

Just for a FYI, if once you stop pressing the pilot button on the gas valve, if the pilot is staying lit it is generating enough power to keep the valve open. So likely the pilot assembly and thermopile is good.

 

[ntobik]

Had some time to work on this again from scratch.

Yesterday sat down and took some notes as I went through.

1) Turned the gas valve from Off to Pilot
2) Depressed gas valve and pushed red lighter button
3) Pilot came on
4) Measured the voltage from the millivolt system, jumped from 0 to 540 in about 45s to a minute
5) Stopped depressing the gas button for pilot, voltage dropped to 340 mV
6) Switched from Pilot to On, voltage stayed the same
7) Flicked the "ON" switch on the front. Voltage dropped to 240 mV, but the burner did fire on.

The burner ran for a few minutes and produced warm water. But after that initial fire it hasn't fired up again.

Checked today, pilot light is still lit. Voltage from the generator is 190. I did some troubleshooting today.

-Moved the gas to Pilot, depressed, got mV up to 500.
-Moved back to On, voltage dropped to 240 mV range
-Flipping on/off didn't change the voltage at all
-Changing the thermostat did. If the thermostat was below the current temperature mV was in the 240 range, moving it into the range where it'd call for heat dropped it down to 170 mV to 190 mV

Any further thoughts?

 

[ps0303]

You have to have a mv reading of at least 400+ in order for the system to operate correctly. Your 190 reading is too low.

What you are seeing is the normal type of thing. When you flip it on it will drop the voltage down some because it's energizing the safeties and they are consuming some of the power. If the pilot is good and strong which I suspect it's not, then once you let off the pilot button the reading would stay up in the 500 range. If I were there servicing it, I would remove the pilot assembly to check and see that it is clean.

Is this propane or natural gas?

 

[ntobik]

It's natural gas. There are two screws that I can use to adjust the pilot light as well as the gas flow. My dad thought maybe the pilot light was gas starved. How could the pilot get so dirty just over the summer?

 

[ps0303]

You should not have to adjust the gas valve pretty much ever. In order to adjust it correctly, if needed, you would need a manometer.

 

[ntobik]

I had looked at buying a manometer on Amazon. Our heater is about 3ft below our pool and the manual said gas pressure might need to be increased in a situation like that.

 

[ps0303]

No that is not true. Gas pressure has nothing to do with where the pool is. Having the heater below the pool would only affect the water pressure switch on the heater in that if not set up correctly could cause the heater to not recognize that there is no water flow and thus allow the unit to fire up or fail to shut off.

I would highly suggest that you hire a local pool heater repair company to come out and look at this issue. They should hopefully have the tools needed to check this out. Unless of course your local gas company provides this service then call them to verify that the gas pressure feeding the unit is correct.

 

[ntobik]

Paul,

I really appreciate the help. I'll give someone a call to take a look at it. Hopefully it just needs to be cleaned out.