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Sight Glass level vs. PSI / Where does the water go?

Rusty2Rusty2 Member Posts: 9
Water in the sight glass drops as the pressure rises. I have a one pipe steam system with 3 mains loops and a Peerless oil boiler. The system was balanced so that this season it ran nicely at .2 (two tenths) PSI and everything worked fine. Recently for some reason the pressure has increased (I don't know why) to about 1.5 PSI maximum. As the pressure rises the water level in the sight glass drops until there is no water in the sight glass so the LWCO kicks in and the burner turns off. This happens as the pressure reaches about 1.5 PSI. The boiler is piped with a Hartford loop by the way. Then as the pressure drops the sight glass fills back up with water and the burner kicks on again. The system continues to short cycle this way. The radiators get hot and the thermostat works. Where does the water go? What happens? Any ideas about this? Thanks

Comments

  • FredFred Member Posts: 8,099
    Is the boiler relatively new? Has any new piping work been done on the system recently? It sounds like the boiler needs to be skimmed. Oils on the surface of the water will make it difficult for the steam bubbles to break through the surface. That can cause the water to be pushed out into the wet returns.
  • Rusty2Rusty2 Member Posts: 9
    Thanks Fred and Hatterasguy, I found the problem. There are 2 King Valves that go to the mains. The valve stems on these can easily be pushed in or pulled out to open or close them. Turning the valve stems in either direction doesn't do anything. One of the valves was partially pushed in, don't ask me how or who did it, but now they are open all the way and the system is working fine. Thanks again for the quick replies. Glad it was something so simple.
  • FredFred Member Posts: 8,099
    Rusty2 said:

    Thanks Fred and Hatterasguy, I found the problem. There are 2 King Valves that go to the mains. The valve stems on these can easily be pushed in or pulled out to open or close them. Turning the valve stems in either direction doesn't do anything. One of the valves was partially pushed in, don't ask me how or who did it, but now they are open all the way and the system is working fine. Thanks again for the quick replies. Glad it was something so simple.

    Sounds like old electro-mechanical valves that no longer have the solenoids attached or working?
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 6,103
    edited March 2017
    or broken internals in the valve. Maybe put a small c clamp, hose clamp or vise grip on the valve stem so you don't have a repeat problem
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