Balancing radiators where TRV is on the return pipe

[bertles01]

Hi all,

I had a new CH system (condensing boiler/unvented cylinder/13 rads/22mm pipes feeding 15mm tails) installed as part of a big renovation earlier in the year and finally getting round to trying to balance the radiators as there are quite a few not getting very warm.

I've noticed that a few of the TRVs are fixed to the return pipes rather than the flow (the pipe tail with the lockshield gets hot first). At some stage I will swap the valves round but would rather avoid it for the moment.

Question is can I still balance the rads as normal using the lockshield valves on the flow pipes? And could the valves being the "wrong" way round be impacting how the rads are heating up (the manufacturer guidance says they're reversible but recommends TRV on the flow)?

Thanks for any help,
Bertles

 

[CBW]

Yes it’s should be doable if they’re bi-directional (reversible). Balancing is making sure an equal amount of heat is distributed to all rads at the same time.

 

[Madrab]

I had a new CH system (condensing boiler/unvented cylinder/13 rads/22mm pipes feeding 15mm tails) installed as part of a big renovation earlier in the year and finally getting round to trying to balance the radiators as there are quite a few not getting very warm.

Should really have been performed as part of the install/commissioning?

Doesn't really matter whether the lockshields are on the flow or return. All you are looking to achieve is by using the valves to restrict the flow to some rads, this allows increased flow to the others to get them all to heat up evenly and at the same time.

 

[oldbuffer]

With decent bi-directional TRVs its better to have the TRV on the end most exposed to the room's air temperature. Having it this way makes the TRV more responsive and in line with the room's actual temperature so that it can regulate the water flow more effectively. So I wouldn't be in too much of a rush to swap the around.

 

[Lower]

Hi all,

I had a new CH system (condensing boiler/unvented cylinder/13 rads/22mm pipes feeding 15mm tails) installed as part of a big renovation earlier in the year and finally getting round to trying to balance the radiators as there are quite a few not getting very warm.

I've noticed that a few of the TRVs are fixed to the return pipes rather than the flow (the pipe tail with the lockshield gets hot first). At some stage I will swap the valves round but would rather avoid it for the moment.

Question is can I still balance the rads as normal using the lockshield valves on the flow pipes? And could the valves being the "wrong" way round be impacting how the rads are heating up (the manufacturer guidance says they're reversible but recommends TRV on the flow)?

Thanks for any help,
Bertles

TRV's don't react to water temperature, they react to room temperature so from a temperature control perspective its irrelevent whether they're fitted on the flow or return.

Lockshield balancing valves are generally recommended to be on the return but will work on the flow side.

 

[Madrab]

Lockshield balancing valves are generally recommended to be on the return

I guess I've never really understood that ... All the lockshield does is allow the flow to be controlled through the rad and then provide a semblance of tamper proofing.

Whilst I agree lockshields are typically placed on the return side of the rad (I do that all the time as normal) I'd guess it's just a legacy thing, whether it's on the flow or return I believe it will behave in exactly the same way when it comes to controlling the flow through the rad for balancing, regardless of which side it's on.

Unless there is a plausible technical reason it is better on the return??

 

[oldbuffer]

Agree with Madrab, doesn't matter which end. However, if one end is in a corner where there isn't going to be much air movement, I prefer to put the lock-shield on that end, so that the TRV can better sense the average air temperature of the room.

 

[Lower]

I guess I've never really understood that ... All the lockshield does is allow the flow to be controlled through the rad and then provide a semblance of tamper proofing.

Whilst I agree lockshields are typically placed on the return side of the rad (I do that all the time as normal) I'd guess it's just a legacy thing, whether it's on the flow or return I believe it will behave in exactly the same way when it comes to controlling the flow through the rad for balancing, regardless of which side it's on.

Unless there is a plausible technical reason it is better on the return??

I suspect the lockshield on the return practice dates back to older systems with large bore pipes and low water velocity. You'd get better control of the flow if there is a larger opening at the flow end of the radiator than the return.

Pure speculation though as i've never found any proper justification as to why it should be on the return.

 

[Harry Bloomfield]

Agree with Madrab, doesn't matter which end. However, if one end is in a corner where there isn't going to be much air movement, I prefer to put the lock-shield on that end, so that the TRV can better sense the average air temperature of the room.

However, even some TRV's which are specified to work on flow or return, can sometimes become noisy when fitted on the return.

 

[bertles01]

Thanks to all of you for the replies and info, really helpful. I'll get balancing!

Also good to know I don't have to do anything too hasty with moving the valves, will just keep an eye on them.