replace TRV thermostat only?

[andy_nufc]

Hi all,

recently moved into new house and one of the bedroom radiator TRVs was cunningly broken off, but placed back on to look like it was ok. Bascially, the plastic feet that the screw collar grips were all broken, so the head is detatched from the pipework. As far as I can tell, the pin is up in its fully up / open position (the radiator gets hot and stays hot when the heating is on.

The TRV sets I've seen in the DIY sheds all seem to be based on a similar design, with what looks like a common collar size. If I buy one of these will it be possible to simply fit the top part of the TRV to the existing valve? I'd rather avoid having to drain down the whole system to replace the piping parts (which to be honest I would get a plumber in to do).

Cheers,

Andy

 

[Boilerman2]

If you can identify the make of valve, you may be able to match a head to fit, but generally a Honeywell head will only fit a honeywell valve, same with pegler, drayton, Herz, bulldog etc etc
it is cheaper to buy a complete TRV (valve & head) than it is to buy a spare head (don't ask me why! )

 

[andy_nufc]

Thanks Boilerman2. It seems to be a standard Myson 2way trv. To be honest it didn't occur to me before to look it up on the internet because I'd not heard of the brand and just assumed it was some crap that Barratt Homes had churned out.

So if I get one, is there any technical impediment to just putting the new head on? should the pin be in the fully up or down position etc?

thanks,

andy

 

[Boilerman2]

will be a straight swap the head is easier to locate if you set it to maximum before fitting (it is not uncommon for the plasic splines to become brittle and break on Myson TRV's )

 

[Charnwood]

but generally a Honeywell head will only fit a honeywell valve, same with pegler, drayton, Herz, bulldog

Not quite true.
Most TRVs share the same fixture. I've replaced a Honeywell VT117 heads with Pegler Terrier and Yorkshire Mistral head and they worked perfectly.
There is a chart on t'interwebnet that shows whether an adaptor is needed for the Pegler I-temp. The ones marked 'Not required', one would assume, means they share the same fixture:

Pegler Yorkshire Terrier Not required
Pegler Yorkshire Mistral Not required
Pegler Yorkshire Belmont 4 Not required
Pegler Yorkshire & Wolseley Bulldog Not required
Altechnic Ecocal Not required
B & Q Regis Not required
BSS BOSS TRV Not required
Comap Westhern 5 TRV AD2
Comap Senso TRV AD2
Comap S2 TRV AD2
Danfoss RAS C2 AD1
Danfoss RAS D2 Revolver AD1
Danfoss RLV-D D Pushfit AD1
Drayton RT212 Not required
Drayton RT414 Not required
Drayton TRV4 Not required
Drayton TRV3 AD3
Grahams Altech Not required
Grasslin Tower TRV REV Not required
Honeywell Rad plan Not required
Honeywell VT117E Not required
Honeywell VT200E Not required
Honeywell VT15 Not required
Myson TRV 2 Way Not required
Myson Petite Not required
PTS Boss Supreme AD2
SALUS SALUS TRV Not required
Screwfix Unbranded TRV Not required
Siemens TRV MTN51GB TRV Not required
Trago Mills Unbranded TRV Not required
Travis Perkins IFLO Not required
Travis Perkins IFLO Contract Not required