Breaking thermostatic valves

[stelladelsud]

What's the most likely cause for a newish thermostatic valve to physically break (other than accidental physical damage)?

We have a 2 year old Keston boiler (sealed system), the system was flushed, sealant used prior to installing the boiler + many new radiators and balanced afterwards (but not successfully).

 

[Burnerman]

Do you mean that the thing has sprung a leak, has a bust off top or just won't work or something? The common problems are that they just don't open up after being turned off for a while - this is due to the valve pin sticking and the solution is to use the things regularly and don't turn them fully off at anytime. They may also leak at the gland, and replacement is the answer here. Other problems occur (like many others) because the system wasn't flushed out thoroughly after the work was done.... Cheers John

 

[stelladelsud]

They've actually snapped off (!)- despite being fairly new. System was flushed prior to replacing radiators and valves. I imagine this means draining down again, just to replace them. But looks as if that is necessary anyway to do an investigation and see why system is still not balancing as well.

Do you mean that the thing has sprung a leak, has a bust off top or just won't work or something? The common problems are that they just don't open up after being turned off for a while - this is due to the valve pin sticking and the solution is to use the things regularly and don't turn them fully off at anytime. They may also leak at the gland, and replacement is the answer here. Other problems occur (like many others) because the system wasn't flushed out thoroughly after the work was done.... Cheers John

 

[Gas2Air]

What make of TRV and sorry to hear you have a Keston.

 

[Burnerman]

I use Drayton TRV4's - they look smart, cost around £20 each, and never had a problem. I guess your fitter must have hands like shovels Cheers John

 

[stelladelsud]

That's what they are Could extreme heat or pressure could cause them to snap?

Just dreading the investigating and fixing (cost/time involved off work/lack of heat during)... Checked out one famous plumbing company and they charge £90+VAT per hour. And that's whether doing an investigation or drinking a cup of tea whilst water pours out of a radiator for 4 hours during draining down...

 

[nickso]

trv4's are bad for going brittle and breaking off the valve.

cheapest option is to get down to a merchant and buy some new heads. you can put them on yourself with not tools whatsoever.

 

[Burnerman]

TRV's arent particularly affected by pressure, but like all other thermoset plastics they can become brittle with age....the plastic top is unscrewed from the main valve by undoing a round knurled nut that holds them on....they should only be finger tight anyway. I really don't know if the valve tops are available separately though - sorry - but it could be worth trying a good plumbers merchant to see what they say. I haven't had any particular problems with the Drayton personally. Mind you, with the plastic top unscrewed and removed, the valve will come fully open, so at least you'll have some heat. Cheers John

 

[stelladelsud]

Thanks guys. If able to replace TRV's without draining down whole system will be over moon!

 

[D_Hailsham]

Give Drayton (Invensys) a call 0845 130 5522 and tell them what has happened. You never know, they may send you the heads for free - after all, they don't want bad publicity.

 

[Burnerman]

Good idea D-H ...... it could be worth buying the complete valve and just using the head, if a drain down is an issue. Cheers John

 

[nickso]

heads are available seperate.

 

[stokj]

I had a complete new heating system with Drayton TRV4 Valves. They have been on for two years and one by one they are all breaking. The top becomes brittle and they literally break off. Easy and quick to replaced but with 18 radiators and costing £20 each this is going to be very expensive. Surely this must be a design fault if they cannot withstand the heat of a hot radiator, which is what they are designed for. There are chrome ones available but these are £30 each ! Any ideas please

 

[Whitespirit66]

Always use Danfoss RAS-C.

Half the price, and no falling apart!

http://www.screwfix.com/prods/33140...anfoss RAS-C White & Chrome TRV 8/10mm Angled