Thehmostatic radiator valves keep failing

[stav1981]

Good morning, I have a question about TRV's in general but mine are specifically drayton TRV4

Mine seem to keep falling, I bought drayton trv4's (7 in total) one failed within a year, another failed after about 3 years, and so on.. I bought these expecting a much larger lifespan. The plastic degrades internally above the screwing in part, then my radiators are basically on max setting until replaced. Just 2 have lasted until 7 years!
I live in the south and I guess its hard water.

I Would like to find a solution to fix this as near to permanently as I can,could you pleae help me acheive this??

should I change to manual radiator valves?
Should I buy rad valves for like £50 each?
Please what can I do?

 

[Johntheo5]

I have used just the mechanical type for years and years and they generallly last 6 to 8 years although I have two that are ~ 25 years old, the plastic part (like yours) generally goes brittle, I am presently using EPH at around £15 each, two of which are installed now for 6/7 years.
Hard water should have no bearing on the failures as the system primary water is "never" replaced, maybe once every few years.

 

[stav1981]

I've had an idea! Could i fit an isolating valve when they fail and turn that on/off or have some control. I am assuming they are very hard wearing compared to a bit of plastic

 

[Johntheo5]

Except they fail with the pin stuck in/down then they do fail full open, (if you remove or break off the plastic head), so you can just control the rad in the traditional way, by throttling the lockshield valve that you allready have on the other side of the rad?.

 

[oldbuffer]

Most isolation valves are not suitable for the constant high temperatures of a central heating system.

 

[Mister Banks]

Good morning, I have a question about TRV's in general but mine are specifically drayton TRV4

Mine seem to keep falling, I bought drayton trv4's (7 in total) one failed within a year, another failed after about 3 years, and so on.. I bought these expecting a much larger lifespan. The plastic degrades internally above the screwing in part, then my radiators are basically on max setting until replaced. Just 2 have lasted until 7 years!
I live in the south and I guess its hard water.

I Would like to find a solution to fix this as near to permanently as I can,could you pleae help me acheive this??

should I change to manual radiator valves?
Should I buy rad valves for like £50 each?
Please what can I do?

Is it the valve body that’s failing or the head?

 

[stav1981]

Its the internals, as you unscrew the valve head and turn it upside down the first thing i see is that the plastic is yellow and crumbles.

 

[Johntheo5]

Its the internals, as you unscrew the valve head and turn it upside down the first thing i see is that the plastic is yellow and crumbles.

But isn't that part of the plastic actuator?,

 

[stav1981]

this is whats happening, im not sure of terminology sorry

 

[Johntheo5]

6 year old EPH TRV head below, looks in excellent condition, I allways install mine horizontally on the return as I think it gives a far more representative air/room temperature, even though I didn't install them to prolong the TRV head life, they run at a (water) temperature of up to 15 to 20C lower than the boiler flow temperature.

 

[Mister Banks]

Honeywell TRV’s for me, 28 years old and still going strong.

 

[oldbutnotdead]

That's the bottom of the head fallen to bits isn't it? (Rather than the valve body). Agreed a year isn't really acceptable, 7 years is only tolerable. I've been using Toolstation 'contractor' valves with Drayton Wiser heads- been in 8 years now, no problems. The TS heads look quite robust, you could do worse...