Heat System wont hold Pressure

**bdryer** · 10-31-2010, 07:19 AM

2 years ago i built a house on a slab and installed 1/2" pex (******* brand, if thats what it is, i dont recall) tubing to specification, per my plumber friend, in my slab. As a cheap heat system i bought a residentual hot water heater and he helped me with pumps, controls etc. it seemed to work fine. last winter i noticed i had to add water alot. now this winter i go to start it up and i cant get it to fill up and hold pressure. i run it up to 30# and come back in 10 minutes and it goes to zero. i valve off the system supply lines and it holds. i have straight water in the system. its not cold enough yet for them to be frozen. i'm afraid to ask this question...didnt sleep at all last night....but is it possible that some where in one of my runs a line froze last winter and burst and now i cant fill the system???? if so, now what am i going to do??

**Thatguy** · 10-31-2010, 10:36 AM

Originally Posted by bdryer

i run it up to 30# and come back in 10 minutes and it goes to zero.

Losing one pint of water in 10 minutes may be hard to find but a cubic foot of water will probably make itself known. How much water are you looking for?
The pinhole leak in my pipe lost a gallon in 3 minutes but that water went into the ground. Still, I could hear the leak 10' away from any pipe.

**bdryer** · 10-31-2010, 06:11 PM

Well. I think i fixed it. I attempted to determine what run it was that was possibly leaking by valving them all off and opening them one at a time. i expected to find one that would drain the system. After the first run didnt give me a problem i opened the next one and so on. some how i was able to open them all and the pressure stayed up. hmmm. oh well, what ever works ! I happy now. thanks.