System pressure ratchets up till relief pops...

Unknown

are you sure there`s no air, trapped in this coil? Is there a place to bleed-it, somewhere at the top?(Of the coil I mean).

Sew- kul

SYSTEM PRESSURE ratchets up till 30 lb. relief valve pops...

I have a system, that has a total of 30ft. of supply and 30ft. of return 1-1/2" piping. It also has a 30gal. holding tank for volume, (1) pipe in at bottom, (1) pipe out on top. For redundancy there are (2)pump circuits with (2) triple duty valves, and (2) 167,000btu. boilers. The system handles (1) Large water coil airhandler with 100% outside air. Water at coil is handled by 3-way valve, so water always flows. I was told, system has been in operation for (7)years. I was called in to replace pump motor and dripping relief valve. System had (1) Model 90 extrol tank. I added a 2nd. model 90 because system should of had a larger expansion tank. I thought the second extrol tank would solve their problem. System still ratchets up and pops relief. Even if system cools, it still does not drop pressure. (Any thoughts on this phenomenon) P.S. The system does not have a fresh water connected feed, it has to be filled manually. Also other than triple duty valves there are no check valves in system...

Sew- kul

Dave, Coil is highest part of system and has air vent at exit side. System runs perfect till it pumps up and relief pops. It take between 24 to 48 hours. When system cools down pressure stays up...

brucewo1b

Sew -Kul

If the system only has a manual feed then there are only two places to get water from the manual valve is not closing tight or if it has a tankless coil/sidearm heater/indirect on it, it is leaking otherwise there is no way to be adding prressure. Now if there is not expansion tank volume or the tanks are not properly charged you could build pressure until the relief valve pops but when it cools down it would have less pressure than when you started.

Sew- kul

Bruce, sorry if I didn't make it clear. System is not connected to any water supply.

Sew- kul

Also the expansion tanks were checked numerous times, because I didn't believe what was happening either. With (0)pressure on system tank precharge is 12lbs. to factory specs.