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Added Honeywell TRV's, now radiators are accumulating water

stevep Member Posts: 37
Hi Guys,

I have a two story house with a one pipe steam system. I've always had a problem with the second floor getting much warmer than the first floor so to alleviate this problem I purchased and installed Honeywell TRV's with temp sensors on (3) second floor radiators:

<a href="http://www.pexsupply.com/Honeywell-V2043HSL10-1-8-One-Pipe-Steam-Thermostatic-Radiator-valve-includes-air-vent">http://www.pexsupply.com/Honeywell-V2043HSL10-1-8-One-Pipe-Steam-Thermostatic-Radiator-valve-includes-air-vent</a>

<a href="http://www.pexsupply.com/Honeywell-T100M2056-Integral-Temp-Sensing-and-Integral-Setpoint-for-V100-and-V2000-Series-Radiator-Valves?source=igodigital">http://www.pexsupply.com/Honeywell-T100M2056-Integral-Temp-Sensing-and-Integral-Setpoint-for-V100-and-V2000-Series-Radiator-Valves?source=igodigital</a>

These three radiators are approximately 25' feet horizontal, and 12' vertical from the boiler. All steam lines are pitched. Radiators are pitched as well.

The problem I'm having is these radiators are now accumulating water and spitting it from the vent. I never had this problem before I installed these vents so I feel this has to be due to poor venting. There are no main line vents anywhere on my system and it's always functioned fine without them, but perhaps these TRV's just aren't allowing enough ventilation?

Would it be advisable to drill/tap an 1/8" NPT into the supply pipe just before the radiator gate valve and install a main line vent before each radiator?


  • stevep
    stevep Member Posts: 37
    edited January 2012
    Think I might be on to something...

    Ok, so after some more research it looks like this particular TRV lacks a vacuum break which is what could be causing the problem. So in order for these to work I'd have to add a vacuum break between the TRV and the radiator. Problem is I'm having trouble finding a suitable vacuum break (1/8" NPT).

    Am I on the right track? If so, does anyone have a suggestion for a suitable vacuum break?

    Seems I could have avoided this entire mess by going with Macon TRV's in the first place as they have an integrated vacuum break, but since I've invested over $300 into the Honeywell products I'd like to try to make them work.
  • RJ_4
    RJ_4 Member Posts: 484

    see my post (auto control of 1 pipe steam )  2-9-12  RJ
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