losing water....

BambiD

central heating, main unit operates on Gas, Radiators are water.
We replced the central unit and all Raditors.
Since then, once a day, we must top up water to the system.
very small quantity at a time to move the guage from low to Normal.
I checked all over the house, no visual leaks, I checked all radiators, looks oK, I vented again all radiators - but still the same, every day, sometimes twice a day, need to fill...
any suggestions?

mattmia2

What kind of expansion tank does it have? Is there any discharge from the relief valve?

EBEBRATT-Ed

Sounds exactly like an expansion tank issue. Could be it was shipped with low or no air pressure or a defective tank. You can check the air pressure in the tank only when it has been removed from the system or isolated and drained. 12-15 psi normally.

With a loss of the air cushion in the expansion tank the pressure gauge will respond erratically to the pressure change as the water heats and cools. Or the tank could be undersized to your system.

BambiD

mattmia2 said:

What kind of expansion tank does it have? Is there any discharge from the relief valve?

the expansion tank is internal.
When pressing the valve, came out some water... I have a feeling thats bad thing.
Should I try to put air into it? to what pressure usually?

BambiD

EBEBRATT-Ed said:

Sounds exactly like an expansion tank issue. Could be it was shipped with low or no air pressure or a defective tank. You can check the air pressure in the tank only when it has been removed from the system or isolated and drained. 12-15 psi normally.

With a loss of the air cushion in the expansion tank the pressure gauge will respond erratically to the pressure change as the water heats and cools. Or the tank could be undersized to your system.

thanks, I will try to look into it

SuperTech

If water came out its shot. Is this a wall hung boiler with a built in tank? Probably the easiest thing to do would be to add an expansion tank to the boiler piping 

BambiD

SuperTech said:

If water came out its shot. Is this a wall hung boiler with a built in tank? Probably the easiest thing to do would be to add an expansion tank to the boiler piping 

Yes it is.
Internal, wall hanged.
As a test, I closed the mains of the Radiator line (in and out), release all water, filled 15 PSI and released more, untill no more water came out.
then, filled 15 PSI , and reopened all velves.
I will see if that helped, If not, I worry that the diafgram is damaged....
then I will have to consider external tank or replace this one.
will update once will have more info

mattmia2

The only way that water can get on the air side is if the diaphragm is leaking.

Jamie Hall

BambiD said:

mattmia2 said:

What kind of expansion tank does it have? Is there any discharge from the relief valve?

the expansion tank is internal.
When pressing the valve, came out some water... I have a feeling thats bad thing.
Should I try to put air into it? to what pressure usually?

It's gone. The procedure to install a new expansion tank is really rather simple -- assuming that there is a valve between the system and the old tank. If there is, before you connect the new tank to the system, set the air pressure in it to whatever your system runs at when it's cold (12 psi is common, but talle houses do need more). Close the valve to the rest of the system, disconnect the old tank, hang and connect the new one. Check the system pressure and if it's all good, you're done.

BambiD

I also think it's gone....
that was my initial tought.
meantime, I did what I wrote above and it's holding pressure.
I'm not supposed its "fixed" but if can make it through the winter, with topping up evrery few days, it will be easier to fix it in summer.
Thank you all for issolating the problem, now I will need to get it fixed.

mattmia2

don't do that, the fresh water will ruin the boiler. replace the expansion tank as soon as possible.