Boiler change - TRVs also?

[riph72]

Hi all,

I've asked for a quote for a new boiler recently, the plumber (who's a nice enough bloke) is advising that I fit TRVs to the radiators at the same time.

He's advising this, not as you'd expect - because of the efficiency etc etc - but because he reckons when they drain the system down and flush it through for a number of hours, there's a reasonable chance that one of my current (old) valves might leak due to the removal of years of crud, and if just one leaks, I'll be asking him back out, and they'll need to drain everything down again, etc.

He reckons it's not so much I should fit TRVs, it's just that it's a good idea to renew the valves while it's all drained down, and TRVs are just a few quid more expensive than standard valves, so I might as well go for them.

Does this seem a good idea?

My mother-in-law has just had a new boiler, none of her valves were changed, but she has a regular system and I have a combi - is this a factor?

Cheers,
Richard.

 

[dcawkwell]

Depends on how old your existing valves are.
If you can happily turn the valves of your radiators off and on without
any leaks then they are fine. Tell him to install and forget
the radiator valves. I've installed many systems and never
had problems with old radiator valves unless they are well past it.
If your plumber is wanting to flush the system he'll be wanting
to turn the radiators on and off so he doesn't want any of
them starting to leak on him.

A replacement standard radiator valve only costs about £2.50 so
£5 per radiator. Average house £35 + time to fit.

 

[gas112]

In theory trvs are meant to be fitted to meet building regs unless customer refuses

 

[ChrisR]

Two issues - leaks and need for TRVs.
They'd only be one end so fitting them doesn't help with an old leaky valve the other end...
Concur - only change rad valves if they look old/leaky,
but do have TRVs on at least the bedroom rads, but always leave the rad where the room stat is with two lockshield type.
TRVs usually stop working before they leak.

 

[Agile]

The Energy efficiency good practice as well as Building Regulations say that TRVs "should" be fitted when a new boiler is installed.

TRVs, used properly, can reduce heating costs by up to about 5% and can give better comfort.

Whilst the system is drained I agree that it would be sensible to replace all the rad valves.

If that advice is not taken then after cleaning the system some of the old valves may start leaking and in my view he would be reasonable to ask that you pay for the cocts of replacing them including an allowance for the time taken to drain down and replace the inhibitor.

Tony

 

[D_Hailsham]

Whilst the system is drained I agree that it would be sensible to replace all the rad valves.

Exactly what the latest Guide says:

"When an individual system component such as the boiler or a room thermostat is being replaced, it is not necessary to upgrade the whole system.

However while not essential for compliance with building regulations, in the case of a boiler replacement, because the system has to be drained down, it would be good practice to install thermostatic radiator valves (or equivalent) on all radiators other than in the room with the main thermostat provided the radiators are suitable and pipework does not need to be altered."

 

[mickyg]

A replacement standard radiator valve only costs about £2.50

yeh if its cheap sh1t

 

[riph72]

Depends on how old your existing valves are.

I've only lived here for 9 months, so impossible to say. The house is 42 years old, so perhaps they are original - is that realistic?

 

[riph72]

They'd only be one end so fitting them doesn't help with an old leaky valve the other end...

He reckoned they are typically £10 each, Screwfix do TRVs at that price that come with the lockshield for the other end too, so it's possible I'll get both ends done, but I need to check of course!

 

[riph72]

Whilst the system is drained I agree that it would be sensible to replace all the rad valves.

If that advice is not taken then after cleaning the system some of the old valves may start leaking and in my view he would be reasonable to ask that you pay for the cocts of replacing them including an allowance for the time taken to drain down and replace the inhibitor.

Just suppose I didn't change the valves, one leaks, and I need to call him out to replace it - what could I expect to be charged for re-draining the system, changing the faulty valve, and replacing the "inhibitor"? (I presume it needs to be replaced and can't be re-used?)

I need to stack this figure up against the cost of getting all the TRVs fitted in the first place!

 

[riph72]

Whilst the system is drained I agree that it would be sensible to replace all the rad valves.

Exactly what the latest Guide says:

"When an individual system component such as the boiler or a room thermostat is being replaced, it is not necessary to upgrade the whole system.

However while not essential for compliance with building regulations, in the case of a boiler replacement, because the system has to be drained down, it would be good practice to install thermostatic radiator valves (or equivalent) on all radiators other than in the room with the main thermostat provided the radiators are suitable and pipework does not need to be altered."

I certainly intend to get them fitted in the bedrooms, but from experience I know they are almost pointless in a fairly open-plan house such as mine. So I'm doubting having *all* the valves changed.

 

[D_Hailsham]

from experience I know they are almost pointless in a fairly open-plan house such as mine.

I wouldn't agree with that.

Although I have never owned an open-plan house, we never close any of the room doors, except for obvious reasons, which means the whole house is at the same temperature. Sizing of radiators is not an exact science, so there is a tendency for installers to oversize, which means that some rooms could get overheated. This will not happen if TRVs are fitted.

 

[gas112]

d hailsham can you put a link to latest guide you refer to. cheers

 

[riph72]

from experience I know they are almost pointless in a fairly open-plan house such as mine.

I wouldn't agree with that.

Although I have never owned an open-plan house, we never close any of the room doors, except for obvious reasons, which means the whole house is at the same temperature. Sizing of radiators is not an exact science, so there is a tendency for installers to oversize, which means that some rooms could get overheated. This will not happen if TRVs are fitted.

What I meant was - I'd use TRVs in the bedrooms where they (from experience in my last house, which was smaller but a similar open-plan style) do tend to overheat a bit, but I might not use TRVs in e.g. the lounge/dining room/hallway/landing, because due to the open-plan nature of the house, these are essentially one large room most of the time.

Having said that, my current thinking is that I'll perhaps use TRVs everywhere except the lounge/dining room, because they are and almost certainly always will be one large area. I might consider TRVs for the hallway/landing, because they can be isolated as a separate area.

 

[riph72]

from experience I know they are almost pointless in a fairly open-plan house such as mine.

I wouldn't agree with that.

Although I have never owned an open-plan house, we never close any of the room doors, except for obvious reasons, which means the whole house is at the same temperature. Sizing of radiators is not an exact science, so there is a tendency for installers to oversize, which means that some rooms could get overheated. This will not happen if TRVs are fitted.

Further thoughts - I do appreciate your point though, that even with the doors open throughout the house, you can still get a hotspot in some rooms.

I'll give this some thought... funnily enough, the more I think about it, I'm actually starting to lean towards just getting TRVs put everywhere like he suggested