Drayton TRV4 Auto-balancing technology

[Milleniumaire]

I'm planning to change some old radiators on my CH system and so was looking to also replace the old TRV's with some Drayson TRV4's, which I've already done on a number of radiators over the years.

I came across a "new" version of the TRV4, which has auto-balancing technology built in. My understanding is that on installing you change a setting based on the size of the radiator/btu output it will be fitted to and I assume the lockshield valve is left fully open, since the TRV then balances the flow through the radiator.

I assume the idea is that on a CH system where all radiators have these auto-balancing TRV's fitted then it should not be necessary to balance any radiators and they would all get hot without issue? However, is it worthwhile fitting these on a system with 16 radiators, when only, for example, 3 radiators have these auto-balancing valves fitted. I guess it would work for those 3 radiators, but then there would be a mix of manually balanced and self-balanced radiators and since these valves look identical to the classic TRV4 versions, it may be difficult to remember which is which. However, I guess that once balanced all the radiators on a system shouldn't need to be changed again, apart from when they are replaced.

Is this new auto-balancing technology worth paying the extra for or is it just a gimmick?

I confess, despite already fitting some of the classic TRV4 valves a few years ago, I hadn't realised they could be altered manually to balance the radiator, rather than balancing using the lockshield valve. I only came across this ability, which requires a special tool that must be purchased, while trying to understand what the new auto-balancing valves actually did.

I would appreciate your thoughts and experiences.

 

[muggles]

They'll still help with balancing the radiators you fit them to but the benefit is definitely greater when fitted to all radiators. Be aware that they must be fitted with the flow entering the bottom of the valve, they won't work on the return

 

[Milleniumaire]

They'll still help with balancing the radiators you fit them to but the benefit is definitely greater when fitted to all radiators. Be aware that they must be fitted with the flow entering the bottom of the valve, they won't work on the return

Yes, I noticed they were uni-directional, whereas the classic TRV4 is bi-directional. Shouldn't be a problem as I'm 99% sure the existing TRV's are on the supply side, but will check to be 100% sure.

I read elsewhere that one of the advantages of these auto-balancing valves is that they take account of the TRV pin position i.e. fully opened, partially closed etc. depending on the heat of the room. I'm struggling to get my head around this as if this really was an issue, wouldn't this cause problems for most CH systems with TRV's fitted, since most will have been manually balanced using the lockshield valve, which wouldn't take account of how open the TRV valve was?

For example, assume a really warm bedroom, such that the TRV is 90% closed i.e. 10% open, or a kitchen were the TRV is 50% closed, or a cold lounge where the TRV is 100% open. Given these various states of the TRV, the lockshield valve is in a fixed position as a result of balancing the radiators on the system, so I wouldn't expect the TRV open/close position to make any difference to this, or does it?