20 Most Recent Amtrol ST-5-C THERM-X-TROL ASME Expansion Tank, 2 Gallon Questions & Answers

it maybe that there is a small leak at the connection.try to remove the tank and put teflon tape on the connection.this may fix the problem.if this does not fix the problem,it may be possable that the amtrol has a pin hole in it.this may hve to be replaced.good luck with your project

air in system bleed air at all radiators

air in the system, bleed the boiler and bleeders at radiators

Has nothing to do with the expansion tank, the expansion tank whole enough air so that when the heater heats the water it does not build up pressure. You know from school that you can compress ait. you CAN NOT compress water. When you haet water it expands until it turns to steam. So lets rule that out.

First look at all the plumbing in the house where there is a cross conection. This would be like a shower valve that has a personal shower head on it. and you turn of the water using the personal shower handle and not the valve at the wall. This then would let cold water to go into the hot water side piping.

Most people do that with out knowing it at the laundry sink. they put a hose on to was the dog and forget to turn off the faucet and then BANG cold water in the hot side.

Go around the house and turn off all the faucets and valves by using the handles. no add on things.

Now last could be the shower valve itself. . Do this happen in just one shower or all of them???

If its just the one and you spend the day doing the walk around, even check the bidet if you have one

its the valve. you need repair to that.

Best of luck in your hunt Tom

Once these start to leak, usually the best solution is to replace the tank. It is corroding and will only corrode more with time. You could try epoxy for a short term fix, something like liquid metal.

These black flakes must be in your line or your expansion tank. Remove the filter from your faucet, temporarily, and let just the hot water side run until the water comes out clean. You must flush these black flakes out. I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

The exspansion tank is more than likly the problem. The temperature/presure valve may also be the problem. Replace both. To replace the exspansion tank turn off the supply water coming into the water heater. Open the relief valve and purge the presure off the tank. drain the water heater slightly below the temperarture/presure valve to replace. The exspansion tanks screws off. Use new teflon taope on the threads when replacing both the exspansion tank and the T&P valve. This work can be compleated by the homwowner with some mecanical inclination.

It seems that you have this figured. In their literature all units are shown vertical, either inlet up or inlet down. Also, it appears that if the unit is full of water, (water logged) pressure will build up in the system. Temporarily, you could shut off water to the water heater, open some drains and use a pump to put some air back into the tank. This would at least get air into the upper half of the tank for a while until you can get set to make a repair.
Gary

The easiest way I know of is to remove cap from air valve on top of tank and check pressure with tire gauge.If you get water out of valve then air bladder is bad and tank will need to be replaced. If you don't get water but no pressure then reinflate to 3-5 PSI. Hope this helps. Thanks

Hi,
You are correct... the tank should not be full... usually the problem is that the bladder inside breaks and then the air escapes....or more accurately is disolved into the water.

The ST tanks are usually used for expansion on domestic water systems to make up for hot water heater expansion. If there is a check valve at the entry point then the tank is needed to allow for water expansion upon heating in the hot water heater. Therefore the bladder pressure is usually about 100 psi +or- depending on the setup. the main thing is that the pressure is lower then the relief valve stting usualy about 125 psi.

The tank can be bought online or at many big box stores and it is easy to replace.
Simply shut off the wwater...isolate as much as possible and then relieve the pressure at the closest point to the tank...
Then just unscrew the tank... dope or tape with thread sealant, the threads of the new one and screw in back into the fitting...

There you are back in business again...

heatman101

yes ,if your tank is under pressure or water logged then when your water expands when heated it has nowhere to go, i'm assuming by the model you described that you are referring to your heating system. you need to drain the pressure down on your boiler to 0 than take an tire guage and check it on the sniffter valve underneath the blue cap. it should be about 15 pounds. if not pump it up with bike pump or compresser.wait for about an hour and recheck if not holding air then discard, you need to save the water you drain and pump it back in somehow, as it could be glycol, or have rust inhiters in it. if you take a reading without draining it will give you a false reading

you are correct....the rubber bladder inside the tank has leaked by and filled the expansion tank. it will need to be replaced and you also may find boiler or water heater relief valves may blow off until its replaced

Sounds like the internal diaphragm has ruptured. The tank should be replaced immediately. You should disconnect the electrical power to the water heater and close off the incoming water supply to the heater. Open a HW faucet to relieve the pressure and remove the tank. Be careful cause you are going to get wet. Replace with a new tank.

In a while the control unit will fail
On the Amtrol units the control is their weakness.Once it starts to buss it will last somewhere between a couple of weeks and a year, but it WILL eventually fail.
And while Amtrol advertise a "Limited lifetime warranty" the "Limited " part includes not putting any warranty on that control unit.

depends on why it was installed in the first place...

most of the time these are installed to reduce thermal expansion... "hot water into the cold pipes"

I don't know your system, but I would just replace it. removing it could potentially bring back, or cause other problems we are not aware of, the reason it was actually installed.

HI sorry its shot, they go every now &then.You can run it like you say temporary BUT the boiler needs low pressure to force heat @10 or 12 p.s.i. This pressure will leak out of the hole and you eventaully loose heat & get noise.If you got a pinhole leak in tank.With the main off.Slow it down with duct tape or a rag if you can and leave water on.