Can't Find Leak

Rich Davis_2

Installed a new system last fall, using a TT PS 60, with a Taco DT circ. It's 1 zone and 4 loops. I don't leave the water supply on. During heating season It would take just under a week for the pressure to drop enough that the boiler wouldn't lite.  So I thought while it's off for the summer I'd find the leak. So I started with the primary piping. I closed all the valves to the loops, secured the pressure tank, also using a Taco 4900 air eliminator  closed that bleed. I pressurized it to 25# it looses about 1-2# a day.  I thought the HE might be leaking so I removed the condisate trap. I can't find any evidence of leaking anywhere. I realize that it wouldn't need to leak hardly anything to get the pressure to drop but went over it carefully and can't find water anywhere. Any suggestions. Thanks

Zman

Would be surprised

I would be surprised if you had a leak that size in the mechanical room without any water dripping or evidence of a leak. I assumed you soap tested all the ball valves and connections? It sounds like the issue is in the tubing. It is not uncommon for air to leak through a ball valve out of  the loop you are trying to isolate. I would  pressure test the radiant loops 1 at a time.

Do you have any reason to believe the leak is new. Your older system likely did not have a low pressure cut off. You may have always had a leak.

Rich Davis_2

It's New

I designed and installed the system last summer/fall. all new equipment. ya, it suprises me too that I don't see water, I thought I'd start with the primary first then move to the loops.  I quess it could be leaking thru a valve. I did leak test with soap and air before I initially added water to the system. Thanks for the suggestion.

Steve Whitbeck

pressure tank

Is the expansion tank still part of the pressurized system? If it is not the leak is on the order of evaporation - the leak would be so small that it would evaporate as it leaked.

The only thing that would keep the pressure on the system with the tank isolated from it would be the brass bellows inside the pressure guage.

The main leak is in one of the loops not in the boiler system.

NYplumber

check the overlooked relief valves

Check the relief valve. It's often overlooked, and sometimes piped to a drain or hidden behind equipment.

ColoradoDave

Cut the system in half

I'd consider cutting the heating circuits and testing  (100psi) all four of them at once and testing the boiler side (25psi) as two tests.

Then that will at least tell you where to start looking.

Although, I'd agree with alot of the other options/opinions stated previously.  I assume since it's all new, you're including the tubing/heat loop piping.. either copper or pex.



~Dave

Rich Davis_2

Good suggestions

Sorry I haven't gotten back to you'all sooner, Thanks guys for the suggestions.  I isolated the pressure tank out so it's not part of the problem. And the inside of the PRV is dry.  I like the Idea of spliting the sysem, that's kinda of what I was doing, but as soon as I get a higher pressure guage I'll use more pressure on the system piping to see if I can find it.  Though the pressure on the near boiler piping has lost 12 PSI in a week. As soon as I figure out how, I'll try and send a photo to show what I have. And Thanks again