A Leak That Is Driving My Crazy

Rich Davis_2

I designed and installed a hot water heating system about 4 years ago. It's a single zone with 4 loops using a TT PS 60 boiler. I"ve had a problem with a small leak, trying to find it. If the system cools down to ambient temp it will lose pressure, to the point that the boiler won't fire when with a call for heat. I manually feed the boiler, I open the fill valve for 2-3 sec it's up to 12 PSI and everything is fine as long as the system stays hot/warm. It's plumbed with sweated pipe. I've been over that system 10-15 times looking for sighs of a leak no luck. The question is, can I put some kinda dye in the system that will show up a leak.

john walsh_2

Do you have baseboard heat or radiators? Do you have a compression tank on your system? Is the boiler not firing due to the low water sensor?

hot_rod

you might need to do a loop by loop pressure test. If you can isolate the loops from the boiler and piping, take them up to 60 psi or so.

Small pin hole leaks are usually those slow gradual type. as the tube warms, sometimes the leak a bit more.

rick in Alaska

I would also check the compression tank to make sure it is expanding properly. It seems if the pressure dropped to zero, it should take more than a couple of seconds for the pressure to come back up to 12. That wouldn't explain why you are losing pressure though.
Rick

EBEBRATT-Ed

You don't have a leak, it's an expansion tank problem. If 2-3 seconds of filling bring you to 12 psi you have no cushion.

Disconnect the tank from the system or isolate and drain the water side...then check your air pressure. It has to match your fill pressure

Rich Davis_2

Thanks for the replys, gets the ol brain cells working. When I service the system before heating season I always check the air pressure in the tank. The next time I'll remove the tank and drain it and start over.

Rich Davis_2

Kinda back to the original question: is there a dye available to help me find the leak. Thanks

hot_rod

Rich Davis said:

Kinda back to the original question: is there a dye available to help me find the leak. Thanks

Food coloring works.

Most auto parts stores have radiator leak detection dyes.