troubleshooting pool heater

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PoolPro

troubleshooting pool heater

Postby PoolPro » Tue 22 Sep, 2009 03:25

There is one situation where boiling water could contribute to the expansion of the heat exchanger. If the heater was isolated by valves and the water began to boil, then the pressure caused by the boiling water would contribute to the expansion of the heat exchanger. However, that still does not change the fact that the banging or knocking is being caused by the heat exchanger overheating and overexpanding, and not by the boiling water itself.


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Pool Clown
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Troubleshooting pool heater

Postby Pool Clown » Tue 06 Oct, 2009 21:44

PoolPro wrote:
I never said that the water doesn't boil. I said that the banging sound wasn't caused by boiling water. Provide a reference that says that the knocking or banging is caused by water boiling.

Have you asked anyone yet "What the banging is"?

I have already provided a reference that says "Water void"; that means "NO" water. I said that the banking or knocking was caused by the heat exchanger overheating and overexpanding, and being damaged.

I've never tried to fire a heater that has no water in it. Why would i or anyone do that? I'll admit, I don't know what a completely dry heater sounds like if you try to fire it.

I also talk to tech support and take seminars

Great, then you can ask the guy "What the banging is"

and I have been doing pool service longer than you have.

Please provide facts that support this.

I was pointing out your inconsistency. You are the one who implied that water would not boil. You are the one who said that the hi-limit would turn the heater off at 108 F. If the heater turns off at 108 F, then how is the water going to boil?

I was wondering if you would ever pick up on this, I intentionally said Hi limit shut off is at 108 to see if you knew what the real temp shut off on most high limits are.

Pool Clown wrote:Are all these manufacturers wrong, and you are right?


Provide references where any manufacturer's statement supports your claims, or is inconsistent with mine. I have provided three references that contradict what you claim.


Provide documentation that says, "the banging is due to the metal flexing too fast, and not the water boiling." since you had been pouring over the Pentair, Hayward, and Raypak pdf's to prove me wrong, which you could not do by the way, It should be easy to find, I'll wait...

By the way, How long do you think momentary means? if not less than 5 seconds? I Don't know where you got the idea that i jump switches for a longer period of time, Other than not stating the obvious "don't leave the jumper on"
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
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Troubleshooting pool heater

Postby Pool Clown » Tue 06 Oct, 2009 21:46

EricVH wrote:I have a Hayward pool heater with millivolt control. The pilot light is lit, the thermostat is set high, and the pump is on with good water flow -- but the heater won't come on when I turn it on.

The control is Model 36D35U, Type 401, PN 1500984901F

I measured the following voltages on the gas control terminals, with the heater switch in the OFF and ON positions (voltages are referenced to the control valve body):

               OFF | ON
------------------------------
TH         0.0 V | 0.072 V
TH+PG   0.5 V | 0.38 V       <---- these TH+PG values fluctuated about +/- 0.04 V
PG         0.0 V | 0.0 V

(I think those letters are correct. "TH+PG" was obscured some by wiring, but I think that's what it said.)

Are these voltages correct, or in the valid range? I'm guessing that if these values are correct, then the problem is with the control valve; and if they're out of range, then the problem is with the thermocouple.

I don't run the heater, but I leave the pilot lit and test it once in a while. Several times when I've tested it before, I've had to try flipping the on/off switch several times before it kicked on. So I know that it's all hooked up right, and the fact that I get different values for the ON and OFF positions tells me that all of the switches and t-stat are right.

I also checked the voltage drop across the on/off switch. I didn't record the values, but it dropped to 0 (or close to it) when I turned it on, so I think the switch is fine.

Any suggestions on how to further diagnose the heater would be appreciated!


Eric, Sorry your thread got high jacked Buddy.
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
Jayss

troubleshooting pool heater

Postby Jayss » Thu 08 Oct, 2009 19:38

First you need to check the thermopile at the gas valve and make sure you at least 500 millivolt.
PoolPro

Troubleshooting pool heater

Postby PoolPro » Thu 08 Oct, 2009 23:41

Pool Clown wrote:I intentionally said Hi limit shut off is at 108 to see if you knew what the real temp shut off on most high limits are.


Yeah, right. You give bad information because you don't know what you're talking about. I suppose all of the other things that you were wrong about were also done on purpose. Don't make me laugh.
PoolPro

troubleshooting pool heater

Postby PoolPro » Fri 09 Oct, 2009 01:03

Pool Clown wrote:Hey, Dr. Johnson, I know I blew up your heater, floated your pool and electrocuted your dog, but I meant to do those things. I was just testing you. I wanted to see if you would notice.


LOL.

At least you apologized to the O.P for hijacking the thread.
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Troubleshooting pool heater

Postby Pool Clown » Fri 09 Oct, 2009 02:02

Ask anyone what the banging is yet?
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
PoolPro

troubleshooting pool heater

Postby PoolPro » Fri 09 Oct, 2009 02:20

Explain how boiling water causes the banging or knocking. I have some water boiling right now. Guess what? No banging or knocking. A slight bubbling sound, that's all.

Have you asked anyone yet?
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Troubleshooting pool heater

Postby Pool Clown » Fri 09 Oct, 2009 02:34

PoolPro wrote:Explain how boiling water causes the banging or knocking. I have some water boiling right now. Guess what? No banging or knocking. A slight bubbling sound, that's all.
You cant compare that to a pool heater, You know that.
I'll give you a hint, What would you think would happen to the steam if you kept it from escaping to the atmosphere? Just let it build pressure.


Have you asked anyone yet?

Yep, years ago, at a seminar. I think it was Raypak. Actually i think i was told, I didn't ask. So i guess that would be a no.

How about you? Where did you learn of "Rapid expanding of the metal" in a heater?
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
PoolPro

troubleshooting pool heater

Postby PoolPro » Fri 09 Oct, 2009 07:53

PoolPro wrote:There is one situation where boiling water could contribute to the expansion of the heat exchanger. If the heater was isolated by valves and the water began to boil, then the pressure caused by the boiling water would contribute to the expansion of the heat exchanger. However, that still does not change the fact that the banging or knocking is being caused by the heat exchanger overheating and overexpanding, and not by the boiling water itself.


The pressure does not build up unless the heater is isolated by closed valves, as I have already noted. And, if the pressure did build up, it would cause the heat exchanger to expand.

You're wrong; you know you're wrong; just admit it.
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Troubleshooting pool heater

Postby Me... » Fri 09 Oct, 2009 09:40

Jayss wrote:First you need to check the thermopile at the gas valve and make sure you at least 500 millivolt.


3 points for Jayss! Make sure the TP leads are not connected to the gas valve when testing. If its a good solid 500 or more look for loose/corroded connections. Heck, tighten them all anyways. The diaphragm in the gas valve can stick closed if it remains shut for a long time. A **gentle** tap with a screwdriver handle under the gas valve might free it. If so turn the thermostat up/down several times to help make sure it stays that way. DO NOT try to disassemble the gas vlave.

Firing the boiler with low water will flash the water to steam which is an explosion, especially in the confined area of a heat exchanger.
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Troubleshooting pool heater

Postby Pool Clown » Fri 09 Oct, 2009 11:46

I'll admit i'm wrong, If you can prove it. So far, I have seen no proof. I've asked you where you got the "metal expands rapidly" theory from, But you won't tell me. Why? I have told you where i got my information from.

Raypak will be putting on free, half day seminars this year across the country. Please go to one in your area, and talk to Tom Apt (instructor) privately, if you don't want to ask in class.
Ask him, "What the banging is" ?
Factory warranty service for Pentair, Jandy, Raypak, Polaris, and Paramount pool cleaning systems.
PoolPro

troubleshooting pool heater

Postby PoolPro » Sat 10 Oct, 2009 01:55

It has always been obvious to me what the banging was. The water flowing through the heat exchanger keeps the heat exchanger below the temperature that would cause damage. A similar effect can be seen by holding a flame under a paper cup full of water. The paper does not burn through because the water absorbs the heat very effectively.

If the water stops moving, it heats up very quickly. At some point, the temperature of the exchanger gets too hot and it expands and warps. If the water does boil, it becomes steam. Steam has virtually no capacity to absorb heat from the exchanger, and the exchanger would get much hotter, much faster.

Therefore, if someone were to tell you that boiling water caused the banging, they would not necessarily be wrong, but they would not be exactly right either. The same thing would happen with no water.

If you hear banging sounds in your water heater, it is most likely due to metal parts that are expanding and contracting.
toofunny

troubleshooting pool heater

Postby toofunny » Mon 06 Jun, 2011 18:28

Too funny does it have to end???
IndoorPoolGuy
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troubleshooting pool heater

Postby IndoorPoolGuy » Sat 10 Mar, 2012 20:43

Hi toofunny! Have you checked this guide to swimming pool heaters at http://www.indoorpoolguide.com/heating-systems

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