Expansion tank problems

[DHD]

Just checked my expansion tank and there was no air pressure, no water coming out of valve either. Pumped it up to 45#. I can see on the pump that air is in when I removed the pump to check again, no air. Went through this several times, same result. The unit is a Watts PET 5.

I spoke with Watts this morning(after I posted) and they said to remove the tank and then fill with air. Tank is filled with water and something about negative pressure in a closed system. The bladder could have drained gradually over time. Someone else suggested the tank can be checked for pressure by closing off incoming water and de-pressurise the tank and then check it while still attached.

What next.

 

[Reach4]

You normally turn off the pump and drain the water before adding and measuring air. Leave a faucet open. If the tank won't maintain the air pressure, the tank is defective. It should maintain pressure for months. If there is a hole in the bladder/diaphragm the air will leak into the pipes.

Having water in the tank should not keep the tank from maintaining 45 PSI of air unless you open a faucet. It sounds as if the tank is probably defective based on the testing you did so far.

There should not be a need to remove the tank for the test and pre-charge setting.

 

[Sponsor]

 

[Master Plumber Mark]

you need a new tank, they all get water logged over a period of time
and probably should all be changed out every 5 years or less...

Most people never check them and they bebome very heavy with water weight
If they are not properly mounted or strapped down, they can cause some
serious damage when the pipe holding the weight breaks . Also we have seen them hanging in place for over 15 years they finall rust out the botttom and flood the home through the rust hole........



they are a pain in the ass.. and no one wants to pay money to maintain or get someone to inspect them

. perhaps you should try just plugging the line off
and see how well your unit fares for a few months without one..


m

 

[FullySprinklered]

Had a slack day yesterday, so I hauled a couple of dead water heaters and maybe seven dead expansion tanks to recycling. Six of the tanks were bladder failures, and the other one had a pinhole leak at the fitting weld. Poor customer was up all night sopping water and wringing towels to save his hardwoods on that one. I can't begin to tell you how much I despise these damn things. They should hold up better than they do.

 

[Jadnashua]

You need the water pressure relieved from the inlet to the ET before you can try to prefill it with air. And, you need a path open so it there is any water left in it, it has a place to go when you blow up/expand the bladder. IF it holds air, it should be okay, but it could be a leaking valve as well - still part of the tank, but a good cap with a rubber seal may help a leaking Schrader valve. Once you have it prefilled, it should be quite light.

 

[Master Plumber Mark]

Had a slack day yesterday, so I hauled a couple of dead water heaters and maybe seven dead expansion tanks to recycling. Six of the tanks were bladder failures, and the other one had a pinhole leak at the fitting weld. Poor customer was up all night sopping water and wringing towels to save his hardwoods on that one. I can't begin to tell you how much I despise these damn things. They should hold up better than they do.

I hate them with a passion....too.. I only install them when it is absolutely 100% necessary..... They will not last the life of the heater most of the time and dont maintain air pressure inside of them . I prefer installing the water heater on bricks into a pan and running the pan to the floor drain.... I also like to run the t+p drain directly into the drain also...... We also have begun to install WATER ALARMS inside the pans... Zircons for on 10 bucks.....

 

[FullySprinklered]

I hate them with a passion....too.. I only install them when it is absolutely 100% necessary..... They will not last the life of the heater most of the time and dont maintain air pressure inside of them . I prefer installing the water heater on bricks into a pan and running the pan to the floor drain.... I also like to run the t+p drain directly into the drain also...... We also have begun to install WATER ALARMS inside the pans... Zircons for on 10 bucks.....

Now that you mention it, I've had quite a few customers who have had water scooting out the popoff line into the yard, with no idea it was happening. I'll have to give that some thought. I like the cheap alarm idea for sure.

 

[Jadnashua]

Anyone ever used the WAGS valve? It not only detects the leaking, but shuts down the incoming water and shuts the unit down as well (it's easier to do that last on some than others).

 

[FullySprinklered]

Now that I can sell. Got quite a few shell-shocked customers who have come home from vacation to a water-damaged home. I'll be doing some research on that, Jim. Thanks.
I'm up in the mountains by a lake myself for a couple of days; then off to the S.C. coast for a week at the beach. No wi-fi at the beach house, but that may be a blessing for all concerned.

 

[hj]

If water does not come out of the air valve, the diaphragm has NOT failed, but you have to do something so the water can be displaced when you repressurize the tank. Either turn off the water and open a faucet or remove the tank from the system before trying to pressurize it.