Tower TRV - HR92 Compatible?

[johnwharrison]

Hi All.

Over time I want to upgrade all of my rads (except one obvs) to HR92 controlled.

However, none of them even have TRV's yet, so I want to get them changed this summer, and then that's one step closer.

I'm looking at these

http://www.toolstation.com/shop/Heating/d230/Radiator+Valves/sd2762/Tower+TRV/p80954

I don't really want to spend much on the TRV body itself as I'm getting smart control of them eventually, so the quality of the TRV head isn't that important to me.

Can anybody offer any advice as to whether these TRV's are HR92 compatible? Thanks!

[johnwharrison]

... and if they are not compatible, can anybody recommend some 10mm TRV's, the cheaper the better? Thanks!!

[johnwharrison]

Hmm, looking at the evohome shop, I might be in luck!

[DBMandrake]

Hi All.

Over time I want to upgrade all of my rads (except one obvs) to HR92 controlled.

Why obviously ? Do you have an automatic bypass valve installed in the system ? If so, you can fit HR92's to all the radiators, and there is good reason to.

If you don't, any time that any zone in the house calls for heat that "bypass" radiator will run whether you want it to or not, and regardless of whether that room is already uncomfortably hot. This is a significant waste of energy especially in mild weather.

On conventional systems where there is only one wall stat you need an uncontrolled radiator to work with the wall stat, however in the Honeywell system effectively every zone has a stat and they are all capable of calling for heat from the boiler. So the only reason to have a bypass radiator is if you don't currently have an automatic bypass valve.

However, none of them even have TRV's yet, so I want to get them changed this summer, and then that's one step closer.

I'm looking at these

http://www.toolstation.com/shop/Heating/d230/Radiator+Valves/sd2762/Tower+TRV/p80954

I don't really want to spend much on the TRV body itself as I'm getting smart control of them eventually, so the quality of the TRV head isn't that important to me.

A cheap TRV head could suggest a cheap valve body though. Don't be caught out buying valve bodies that turn out to be too cheap or not fully compatible with the HR92's...

When we moved in and got conventional TRV's fitted (there were no TRV's in the house at all before that...) the engineer used cheap Peggler Bulldog TRV's - as I knew I was going to fit Evohome later I wasn't too worried about the quality of the TRV heads themselves (good job I wasn't, turns out they're crap, and I've already had two fail...) but I didn't think about the quality of the valve bodies that came with the heads.

Yes they are compatible with the HR92 without any adaptor, and worked fine for a while, but after about a year nearly half the valves around the house have become "sticky", where the opening/closing point of the valve is inconsistent due to the pin not moving smoothly. (I suspect a swollen o-ring on the pin is causing it to grab) This is apparently a known flaw of these valves.

The symptoms it causes is I sometimes see zones going over temperature because the valve won't fully stop the flow until the HR92 screws the valve pin right down hard - less than "10% opening" as reported by the HR92 in the config menu. (Normally a valve will close at about 40% pin travel)

If the closing point was consistent the HR92 would adapt to it but the stickiness causes the closing point of the valve to keep changing so it makes life hard for the HR92 and the temperature is not regulated nearly as well as it should be.

Because of this and the fact that its only likely to get worse and spread to the remaining valves around the house I'm now faced with replacing all the TRV valve bodies on 9 radiators with better quality ones when I do my next drain and flush. No mucking around this time, I'll be getting the Honeywell Valencia valves so that I have confidence that they will both work well with the HR92 and be of high quality.

As the evohomeshop sells the TRV valve body by itself (just for the one side of the radiator) without TRV etc it brings the price down a lot so the 9 valves I need will be a little over £100. Lesson learnt - don't buy too cheap on the valve body.

... and if they are not compatible, can anybody recommend some 10mm TRV's, the cheaper the better? Thanks!!

Remember you can use internal reducers for standard 15mm valves. My valves are a mixture of 8mm microbore and 15mm, so I'll be using 8/15 reducers on some of the 15mm Honeywell Valencia's. You can buy a pack of 10 reducers for around £5 online.

You can get the Valencia in an 8mm version too but then you have to buy a full kit including lockshield valve and TRV head, which I don't need. Only the 15mm version is available on its own.