I have searched the other questions, and didn't seem to find the same situation, so I am asking again. I have a 1991 (?) 40 gallon AO Smith Power Shot Energy Saver tank in a house that we purchased a few months ago. The tank worked fine until the last few days, and then the pilot goes out every day or so. It relites properly, and stays on through multiple cycles. The power vent is 3" PVC pipe direct to the outside, approximately 18 feet away, and the unit is in the basement with sufficient space around it. It seems that the thermocouple is OK due to multiple cycles, but that may not be the case. Gas pressure should be fine as the burner looks good, and the furnace operates satisfactorily. I realize that the tank is quite old, but am trying to avoid replacing it for obvious reasons. Should I start by replacing the thermocouple, or is there some other path to take? I operated the pressure relief valve and then snapped it back, but there is still a VERY slight dripping from the valve. It is connected by clear vinyl tubing to a floor drain. Does that have anything to do with the operation, or is it strictly for safety?

Hey DIY4u...

Please give us a model number and a serial number so we can look up the exact model and advise properly.

The relief valve is a safety device that is absolutely required to work properly! If dripping and re-snapping the toggle lever at the top of the relief valve doesn't stop the dripping then plan on replacing this T&P valve. DO not cap or eliminate this device as it SAVES LIVES!

Let us know more and we can help!

I'm just not sure if you have a THERMOCOUPLE or an electronic ignition source..?

MARK

The model no. is FRS40216, and the S/N is MG92 0026562-216, and it is equipped with a thermocouple. I will not cap off the pressure relief valve, and, currently as stated, there is only a very slight drip (one every 6 seconds?) but running into the floor drain. This can certainly be replaced.

Hi DIY4U...

This model is so old that the numbers will not come up on the website.

By chance do you hear a dripping sound when this heater first begins to fire... or say about 5-10 minutes after starting to heat the water? Let me know.

Check your instructions (should be on the side of the heater) and be sure there is no thermal cut outs, vapor switches or anything else like that and if not, then I say that you replace the thermocouple as it only costs about $8.00 to buy and is pretty easy to replace.

Also.. the clear vinyl tubing for the T&P discharge... if it is flexible then it is not safe and should be piped up solid over to the floor drain. Plumbing codes everywhere require that the T&P discharge piping be full size 3/4" and that it not be reduced in any way. It can be copper or plastic piping... but not vinyl..? Just FYI... ;)

Sorry I couldn't pull up the correct model... heaters have changed so much the last 10 years that it is hard to be sure of each POWER or DIRECT vent system out there.

Let me know what you think...

MARK

Quote:

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Originally Posted by massplumber2008

Hi DIY4U...

This model is so old that the numbers will not come up on the website.

By chance do you hear a dripping sound when this heater first begins to fire...or say about 5-10 minutes after starting to heat the water?? Let me know.

Check your instructions (should be on the side of the heater) and be sure there is no thermal cut outs, vapor switches or anything else like that and if not, then I say that you replace the thermocouple as it only costs about $8.00 to buy and is pretty easy to replace.

Also..the clear vinyl tubing for the T&P discharge...if it is flexible then it is not safe and should be piped up solid over to the floor drain. Plumbing codes everywhere require that the T&P discharge piping be full size 3/4" and that it not be reduced in any way. It can be copper or plastic piping...but not vinyl..?? Just FYI...;)

Sorry I couldn't pull up the correct model...heaters have changed so much the last 10 years that it is hard to be sure of each POWER or DIRECT vent system out there.

Let me know what you think...

MARK

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I did not see any reference to a thermal cutout or vapor switch. Interestingly, the tank has cycled through about a 36 hour period with no problem - it's just toying with me, I think! I'll try replacing the thermocouple to see if that does it - if not, I guess it's time for a new tank. There is about a 3' length of copper pipe coming out of the T&P valve - I just put a 1" dia hose over it and the other end down in the floor drain - it is stiff enough that there is no chance of it coming out, but the end of the copper was about 12'' off to the side of the drain, and I wanted the water to go into the drain. Does that create a problem?

Thanks for your help!

Hey again.. :)

TECHNICALLY:

The T&P valve discharge pipe should not be DIRECTLY connected into the floor drain. It should be run in 3/4" copper tubing to just above the drain so that there is an 1.5" - 2" AIR-GAP between the floor drain and the pipe (install block/hanger under pipe). This air-gap is in case the sewer ever backed up which could potentially block the discharge tubing (especially over time). The copper is required because a soft hose could get crushed and prevent satisfactory discharge from the T&P valve in the case of excessive temperature and/or pressure...

And not trying to make a big deal of it...I swear, but more so to inform you (and others that read this in the future), check out this link to see what happens when the T&P valve gets blocked/capped... pretty scary!

www.waterheaterblast.com (scroll to bottom of page to play video)

Anyway, I'm sure you are fine for a few days... but when you go to replace the T&P valve be sure to re-pipe this so it is correct!

And this is only an example from a 12 gallon water heater... ;)

One last idea on the heater would be to tighten the thermocouple connection to the gas valve say an 1/8 turn or so.. see if that may improve the contact!

Let me know how this works out...

Thanks...

MARK

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