Radiator thermostat restricting flow?

BigBigEd

I have an apartment that was overheating. Old rads with 1.25 diam supply and return.

I installed thermostat valves (danfoss) on the larger rads to restrict flow.

Now I can't get enough heat out of these rads. I removed the valve head completely to force the danfoss valves fully open, and still not enough flor/heat.

I'm thinking the inside diam of the valves must be too small??

I'd hate to have to remove then and return to larger valves.

Thoughts?

EdTheHeaterMan

This all depends on the piping system your radiators are connected to. Ate there monoflo® tees on a one pipe system? TRV's will not work on that system.

neilc

here's another possibility,
I just installed TRVs on a set overheaters,
2 went dead cold,
turns out flow is reversed thru the 2 rads,
and flow was shutting the sprung discs down tight,
put manual valves back on those 2 naughty rads,
more better now.

BigBigEd

EdTheHeaterMan said:

This all depends on the piping system your radiators are connected to. Ate there monoflo® tees on a one pipe system? TRV's will not work on that system.

2 pipe system....supply and return.

BigBigEd

I was looking at a pic of the install......I think I may have figured it out....can you see the problem??????

neilc

they look the same as mine,
flow reversed ?
is that needle floating down ?

hot_rod

A bit of an air trap with the valve 45ed up like that.

Also, ideally the valve is horizontal, but it should work with that distance from the radiator.

JUGHNE

Plumbed backwards??

Usually the valve part with the spud goes into the radiator.

Big Ed_4

The valve is installed too high and no air vent . Do they make one where the union is on the horizontal to go straight into the radiator ? To remove the trap...

hot_rod

Do you know the flow direction? They only work properly with flow in the correct direction. Should be an arrow on the valve body.

pedmec

valve is installed backwards.

EBEBRATT-Ed

I think @JUGHNE wins this one. Valve looks backwards.45 makes an air trap. Also what keeps the water from short circuiting through rad?

EdTheHeaterMan

Who designed the repipe to get the valves in that way? I believe the original valve didn't need all those extra fittings.

As far as having both the supply and the return at the same end, some old radiators were designed that way on purpose with internal baffles to direct the supply water to the far end before making that turn back to the other opening.