TRV's on old radiators

Steve D_3

worked.

THANKS

Why didn't I think of that? I did substitute a foot for the pipe on a LARGE crescent wrench and it spun out.

I will order my valves now.

Steve

Steve D_2

TRV's on old radiators

I need to put TRV's on my upstairs cast iron radiators to solve an overheating problem and hopefully save some money. I attempted to remove the stub piece of the valve but could not. Can I use the existing stubs with a valve from Danfoss or Honeywell? The valves I want to replace are Kennedy brand from around 1938.

Alan(CaliforniaRadiant)Forbes

TRV

The old stub and nut probably won't fit the new TRV. You have to remove it and as you know, it's hard to get off.

We usually cut the stub off, remove the nut and then carefully cut the remaining nipple from the inside of the pipe at two points and then chisel out the pipe.

Here's a picture of Ron, Jr. doing a relief cut on a steam pipe:

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Mike T., Swampeast MO

I attempted to remove the stub piece of the valve but could not.

Very difficult to do that. Even with a new spud wrench that fits perfectly, the soft brass lands that engage the wrench will frequently shear off. Remove the "stub" AND the tapping bushing it's screwed into. BIG wrench and cheater bar are usually required. You probably won't find decorative bushings, but plain ones are easily available and work fine in nearly all cases.

Can I use the existing stubs with a valve from Danfoss or Honeywell? Extremely doubtful. Unions work via metal-to-metal contact and the geometry of the mating surfaces varies among manufacturers. You can attempt as the threads will probably mate, but don't force! Tighten by hand--you'll be able to tell if it works as the joint will be very firm with no side-to-side slop.

Alan(CaliforniaRadiant)Forbes

TRV

You've got to get the old stub out; the nut won't fit the new TRV.

We usually cut the ground joint off, remove the nut and carefully make two relief cuts from the inside of the remaining nipple being careful not to cut too deeply into the male threads of the radiator. The cut nipple should then be easy to remove with a tap of the chisel.

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Steve D_6

TRV install and old sealants.

I am working with the radiators in my house now. On a test radiator that was hanging around, both the bushing and tailpiece were removable without impossible effort.

With a bigger wrench and more confidence I tried to remove both the bushing and tailpiece from a just drained radiator -- no luck.

Tonight I put the spud wrench and the tailpiece turned out.

Is there a sealant that expands with water that makes the wet parts very tight but more workable when drier? Nothing is visible in the tap of the bushing or the male threads.