Percolating TRV's

mel rowe

I have a TRV on almost all my rads. Several of them (one especially) seems to fill up with water over several days and start percolating like a coffee maker and I have to remove the TRV and dump it. I've tried changing to another TRV, but it does the same thing. Any suggestions as to why and what I can do to fix it?

Mike T., Swampeast MO

I'm guessing here:

Steam system?

No vacuum breakers on the TRVs?

mel rowe

Yes, Mike you are correct. The TRV brand is Honeywell-Braukmann. No vacuum breakers that I know of, but I don't have the problem on most of them. How does this cause the condensate to collect in the TRV? Thanks for the help.

Mike T., Swampeast MO

I'm NOT a steam man but I'll try...

High pressure goes to low.

As the rad fills with steam it vents the air through the TRV. When the steam collapses into condensate it tries to produce a vacuum in the radiator. Unless there is a vacuum breaker to allow air back into the rad, it actually tries to suck water from the boiler.

mel rowe

All 3 mains on my one pipe steam system have Gorton vents, which I know relieve the vacuum in the system, as I can hear them venting air back into the system. When the ststem is operating, and the TRV is making the gurgling noises, seems like any vacuum in the rad caused by condensation would only draw in more steam, and maybe even pull the condensate out of the TRV. I have even increased the pitch on the rad, to try and drain the water out of the TRV. Still have to take off and clean out every 2-3 days.