No TRV flow with pin up

[ASB1960]

I have a rad which I can can't get hot. It's a reina rad with a reina TRV. (Its a full height vertical rad and the TRV is vertical).

If I remove the head the pin can be pressed down and springs up.

When UP there appears to be no flow. As I press the pin - with heating and pump on I can hear flow after about 1mm.

As it is further pushed down the flow seems to reduce (quieter) and stops when fully down.

It seems bizarre that it needs partly pressung to get flow. If I refit the head (not fully tightened) and turn it to around 4 I can get flow. (The rad reasonably quickly becomes warm, but not as warm as others).

Any suggestions.

(I believe the valves are not bidirectional, and that they are on the flow side - but unsure how to be certain).

 

[baldykev]

When was the rad fitted ? has it ever warmed up ?

 

[Mister Banks]

With the radiator cold turn the heating on and feel each pipe on the radiator, the warm one is the flow, the cold one the return.

Is the radiator connected to the pipe work the correct way around?

 

[Wayners]

I've known tvr with pin down and turned off but water still flows.
Tvr needs swapping.

 

[ASB1960]

I installed the rads in the summer. I used the lockshield and the trv the same way round as the original "normal" rads.

I didn't do anything other than a quick test at the time. No balancing (then).

The new radiators got warm (not particularly hot) but this one was cooler. Previously the original radiator didn't get particular hot anyway. It was always holdable. (I just put this down to it being furthest from the pump and maybe not well balanced).

Having checked this morning, the lockshield is on the flow and the TRV on the return. (I guess the original had a bidirectional valve).

I would prefer to keep the valve on the current side (the other side is close to room corner).

I guess my first thing is to replace the valve with a bidirectional one.

I have been trying to balance without too much success. I don't have a great thermometer though.

The top floor has 3 x 15 year old standard rads. The pump is on this floor.

With the lockshields only 1/8 turn open they get very hot very quickly (too hot to touch). The TRVs are right down.

The middle and ground rads ( barring this one ) then get warm, to a considtent temp. The ground floor takes a few minutes longer.

I guess then being warm rather than hot is just a design characteristic. Though I do feel they should be hotter.

I doubt I will change the TRV until summer when the boiler is serviced.

The pump is running on 3 (of 3), the boiler - baxi 619 heat - is running at 70 degrees. It doesnt seem to cycle excessively but does seem to turn off before the thermostat temp is triggered.

 

[MeldrewsMate]

....When UP there appears to be no flow...

...(I believe the valves are not bidirectional, and that they are on the flow side - but unsure how to be certain).

For the purpose of getting your radiators hot it is not important that your TRVs are bi-directional; that only becomes relevant once they start to modulate.

What evidence do you have for there being no flow when the TRV pin is up? Noise? Noise is generated when the TRV restricts the flow; if it's fully open it is possible that there is very little noise.
Have you waited long for the rad to heat up when the TRV pin is up?

I suggest opening the lockshield valve fully on the warm/cool rads, which you have stated are at the lowest part of the building.
The evidence given is that very little lockshield opening (1/8th of a turn from closed?) is enough to get the top rads HOT. Leave them alone. Move on to other rads on the top floor (including any hot water cylinder), gagging thier lockshields down until they are hot at the flow end but noticeably cooler at the return end.
Move onto the floor below, and adjust its lockshields as above.
WAIT for temperatures to stabilise before moving to the ground (lower) floor. Are these new rads now performing better?

MM

 

[ASB1960]

That will be a job for tomorrow. I will report back.

The hot water is off. There is a motorised valve on the circuit and this is closed. There is a motorised valve also on the heating circuit and this is open.

There is no cold rank. Its a pressurised system. The pressure vessel shows 1.9 bar.

 

[ASB1960]

MeldrewsMate,

I replaced the circulation pump, the old one was getting very hot and was noisy and 15 years old. This improved things a little bit.

After much fiddling I discovered that the valves seem to be very sensitive to how the lockshield is adjusted.

With the lockshields open and heads not fitted (which I would expect max flow) none of the rads warmed. The same was true if only 1 rad had an open lockshield.

I used a stethoscope to listen for flow. Opening the lockshield more than about 3/4 turn stopped flow. I imagine because the pressure drop was such that valve couldn't stay open (seems odd, but was happening).

The final rad on the circuit has the trv firred on the return not the flow. It's marked for flow side. I can't get this one to warm. I guess I will replace rhe valve when the system is drained next.