Radiator TRV query

Pauli11

Pauli11

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I have just fitted 12 TRV's to my radiators where there were none present before.
Having read a bit online, most people seem to reckon leave the TRV about 3. However, at 3, my radiators hardly heat up, I have to leave all the TRVs at 5! Also, I have noticed, that some radiators with the TRV set at 5 still seem restricted and cooler towards the bottom. I had all the TRVs on with the screw collar tight, but I have had to lose the collars on some of the TRVs (even when on setting 5) to get a reasonable flow through the radiator. Is this normal, or am I doing something wrong?

I had hoped to have control of the heat gradually from 0 to 5, but it seems its all or nothing, ie setting 5 or cool rads on anything below 5.
 
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Something definitely amiss there. You should get full flow to the rad, until the room nears the temperature set on the TRV, when it should begin to modulate the flow through it. How was it before you installed the TRV's?

What make/model are the TRV's, might they have been fitted on the return, rather than the flow end if they are not a universal type?
 
Cant remember the make tbh, I bought them back in March. It does seem strange. I have two heating zones, bedrooms and rest of house.
In the hall and main bedroom where the two Nest thermostats are, I haven't fitted a TRV on the rad. These heat up really hot. However, if I go to the other TRV fitted rads, anything under 5 and they are noticeably cooler. At 3 they hardly heat at all. I now have them all set at 5, which kinda defeats the purpose of having them. Like I say, even at setting 5 (max) I have had to loosen the fixing collar a bit, and there is a noticeable sound of faster running water through the valve when I do. I would have expected 5 to be 100% flow, but there is definitely a restriction on setting 5.

So are you saying that if for eg I have the try set at 3, the rad should go to 100% heat initially, only reducing as the room reaches the theoretical temperature for setting 3?
On mine setting 3 will not allow max flow at all, so the rad only gets above Luke warm
 
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ae235
You can see the two arrows on this picture showing either direction, if only one arrow then must be mounted right way around, I have used these
886GV_P
as then I know temperature set and can program them, cost around £10 bluetooth version around £15 one shown is the eQ-3 the Terrier i30 very similar.

The problem is setting the valves, I found this out with my mothers house, I got 4 Energenie MiHome heads which unlike the cheap versions it shows both current and target temperature. The lock shield valves were wide open when I started I closed them to force water around the furtherest radiators on start, however I found the heat was over shooting the setting, so I slowly closed them until they were not over shooting, then I took one of the heads and fitted temp to other radiators and did the same, once the lock shield was set, put the wax head back, and found rooms were spot on after.

However moved to this house and not so easy, with the gas modulating boiler the boiler runs for a long time, but with oil the boiler switches off/on so harder to set up.
 
Are the rooms cold or at desired temp?
If the TRV head is up to temp, it will restrict the flow... Even on highest setting.
 
Pauli11 said:
Just checked, the brand is Honeywell.
Click to expand...

If you don't know the model name, some photos of your actual valves would help a lot.

As well as showing the flow direction arrows, feel the two radiator pipes. The hotter one is the "flow" and the cooler one the "return". Which pipe are your TRVs on?

You also need a thermometer to find out your room temperature. This is what causes the TRVs to open and shut.
 
Pauli11 said:
I have just fitted 12 TRV's to my radiators where there were none present before.
Having read a bit online, most people seem to reckon leave the TRV about 3. However, at 3, my radiators hardly heat up, I have to leave all the TRVs at 5! Also, I have noticed, that some radiators with the TRV set at 5 still seem restricted and cooler towards the bottom. I had all the TRVs on with the screw collar tight, but I have had to lose the collars on some of the TRVs (even when on setting 5) to get a reasonable flow through the radiator. Is this normal, or am I doing something wrong?

I had hoped to have control of the heat gradually from 0 to 5, but it seems its all or nothing, ie setting 5 or cool rads on anything below 5.
Click to expand...
Could it be due to low flow from the pump? What setting is the pump on? It might be on the way out. I had a pump which seemed OK, but needed max setting. When it failed (srarted vibrating badly) the new one needed minimum setting and the whole system worked much better. The old one was full of clag inside and behind the impeller, so performance down.
 
Pauli11 said:
In the hall and main bedroom where the two Nest thermostats are, I haven't fitted a TRV on the rad. These heat up really hot. However, if I go to the other TRV fitted rads, anything under 5 and they are noticeably cooler.
Click to expand...
Havw you balanced the system?
 
ericmark said:
ae235
You can see the two arrows on this picture showing either direction, if only one arrow then must be mounted right way around, I have used these
886GV_P
as then I know temperature set and can program them, cost around £10 bluetooth version around £15 one shown is the eQ-3 the Terrier i30 very similar.

The problem is setting the valves, I found this out with my mothers house, I got 4 Energenie MiHome heads which unlike the cheap versions it shows both current and target temperature. The lock shield valves were wide open when I started I closed them to force water around the furtherest radiators on start, however I found the heat was over shooting the setting, so I slowly closed them until they were not over shooting, then I took one of the heads and fitted temp to other radiators and did the same, once the lock shield was set, put the wax head back, and found rooms were spot on after.

However moved to this house and not so easy, with the gas modulating boiler the boiler runs for a long time, but with oil the boiler switches off/on so harder to set up.
Click to expand...
Harry Bloomfield said:
..and do the installation instruction state they can be installed on either the flow or return of the rad?
Click to expand...

Hi, thanks for the replies. yes, the valves have the two arrows. I should have stated, the rad I was talking about has the Honeywell TRV, the other new ones I fitted don't have a brand one them, photo below. But they all have the 2 arrows. Alsothe issue I mentioned in the first post is apparent on several of the rads.
 

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ericmark said:
ae235
You can see the two arrows on this picture showing either direction, if only one arrow then must be mounted right way around, I have used these
886GV_P
as then I know temperature set and can program them, cost around £10 bluetooth version around £15 one shown is the eQ-3 the Terrier i30 very similar.

The problem is setting the valves, I found this out with my mothers house, I got 4 Energenie MiHome heads which unlike the cheap versions it shows both current and target temperature. The lock shield valves were wide open when I started I closed them to force water around the furtherest radiators on start, however I found the heat was over shooting the setting, so I slowly closed them until they were not over shooting, then I took one of the heads and fitted temp to other radiators and did the same, once the lock shield was set, put the wax head back, and found rooms were spot on after.

However moved to this house and not so easy, with the gas modulating boiler the boiler runs for a long time, but with oil the boiler switches off/on so harder to set up.
Click to expand...


I might try that TRV. Although Im reluctant to fork out more money until I find out what's causing my issue.
 
dilalio said:
Are the rooms cold or at desired temp?
If the TRV head is up to temp, it will restrict the flow... Even on highest setting.
Click to expand...

Thats when I noticed the issue. The rooms in question were not up to temp, and the rads were not at full heat. I understand they should come on at full heat until the desired temp via the TRV dial is reached. The only way I can get these rooms to match the heat in the room with the thermostat (19.5 deg normally), is to leave the TRV at 5.
 
Last edited:
JohnD said:
If you don't know the model name, some photos of your actual valves would help a lot.

As well as showing the flow direction arrows, feel the two radiator pipes. The hotter one is the "flow" and the cooler one the "return". Which pipe are your TRVs on?

You also need a thermometer to find out your room temperature. This is what causes the TRVs to open and shut.
Click to expand...

Ive posted some pics above. I done the hot/cool test on each rad before fitting. They are all on the 'hot first' pipe.
 
fixitflav said:
Could it be due to low flow from the pump? What setting is the pump on? It might be on the way out. I had a pump which seemed OK, but needed max setting. When it failed (srarted vibrating badly) the new one needed minimum setting and the whole system worked much better. The old one was full of clag inside and behind the impeller, so performance down.
Click to expand...

No, the pump was fine, Ive had it for about 7 years and all the rads with the old valves fitted were piping hot. No issues with cool rads anywhere in the house. When I set the TRVs to 5 the rads are piping hot as well. Its just the fact that anything under 5 and they are way cooler and not heating the room.
 
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