OK to drip riser with 17C trap?

brian_27

We're buttoning up our kitchen renovation, the pipefitters finished reinstalling risers and returns through kitchen walls to upstairs radiators. They were unable to get one of the horizontal runs to a riser sloped correctly, and I've got water stacking in the riser. Is it OK to use a 17C thermostatic trap to drip that riser (right at the elbow where it heads up into the wall)? I'm thinking a 3/4" 17C.

THANKS

Brian

DanHolohan

You would have to

use a cooling leg before the trap.

brian_27

thanks for the reply - if I may - the cooling leg would be required for an end-of-main drip, as I understand it. My situation is I have a vertical riser that you can hear the water boiling inside (3/4", feeding two small 2ft. tall 10 column cast radiators). The riser comes off the main at not quite 45 degrees (fitters did not get it quite right), so when it goes horizontal the end of the horizontal run, before it turns up into the wall, is lower than the beginning of the horizontal run, preventing the condensate from draining back into the main and getting pushed out the F&T (see attached). I'm thinking of putting the thermostatic trap where it turns up, the condensate would drain out the trap after each cycle and then steam would go up the riser at startup (after pushing a little more condensate out from the steam hitting the cool riser. Neither radiator is heating all the from top to bottom, new trap elements.

THANKS

Brian

DanHolohan

It might work

the thermostatic trap needs a 10- 15-degree drop in temperature to open, though. That's what the cooling leg is for.

Steamhead

Brian, what are you dripping the riser into?

> the thermostatic trap needs a 10- 15-degree drop

> in temperature to open, though. That's what the

> cooling leg is for.





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Steamhead

Brian, what are you dripping the riser into?

If the return line you will connect the drip to is below the boiler's water level, you don't need a trap. The water standing in the return will "seal" the drip so no steam will enter it.

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brian_27

Dan and Steamhead thanks for replying.

Dan: I'm not sure I need the trap to open during the heating cycle, the pipe is insulated, I want it to drain after heating cycle and at startup.

Steamhead: this would be dripped into the dry return.

I love steam heat but this hammer is absolutely driving me insane!

Brian

Steamhead

OK, you'll need the trap

and it must be ready to drain any time condensate reaches it. That's why you need the cooling leg. Or, use a float trap that doesn't depend on cooling to open.

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