Help choosing the right TRV's for my central heating system.

[rthirlby]

Hi everyone, my first post here so hope it is in the right section.

I am having some work done on my central heating system including a new boiler and a magnatite cleaner but I would also like to take the opportunity to change the standard valves to thermostatic radiator valves.

The reason for this is a few of the old valves are leaking so need replacing anyway so I thought I might aswell fit TRV's. I dont have a massive budget so I wont be able to afford the likes of drayton TRV4 valves, I will be looking at the cheaper end of the market.

The pipework to my radiators is 10mm and I have standard basic radiators. Do radiators differ on the connection size?

My gas-safe man who is doing some work for me says he will fit new TRVs for me free of charge if I supply them. Unfortunately he is away on holiday at the moment so I cannot ask him to show me which valves are suitable.

I have a feeling I should be looking for some with a 1/2" tail (is that the right term) and it must be suitable for 10mm pipe.


Any help greatly appreciated as I am lost!

I could post a photo later tonight if required?

Thanks,
Rich T

 

[Bartdude]

I fit these most of the time. Screwfix stock them at a fair price,can't post a link though,it won't work on here.

Angled TRV - Comap Westherm 5 Thermostatic Valve on eBay (end time 02-Mar-11 13:00:06 GMT)

They're available in 10mm,makes them a bit more expensive. Or just get 15mm with a reducing kit.

 

[rthirlby]

Thanks for the link, I was hoping for something a little cheeper.

Would these work?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250768540608

Do all TRVs have a standard size fitting for connecting to the radiator side?

 

[Essex Fitters]

They will be fine, Its just the reducer you must have.

If you attempt to do them your self be careful not to over tighten as the olives tend to split in the reducer.

My advice is to tighten gently then pressurize the heating system... Worst cause scenario is they they will weep with water, just tighten little more until the water stops.

 

[rthirlby]

Sorry I don't understand, do the ones I linked to not come with a reducer if it says 15 & 10mm fittings?

 

[Essex Fitters]

Yes they do...

just saying if you were to attempt this repair you need to be careful when tightening

 

[rthirlby]

So your absoloutely positive that there is no doubt these ones are right? There's no reason they won't fit? Radiators don't have different sized connections?

 

[Essex Fitters]

your plumber would be able to fit them. BUT please please buy the twin pack from screwfix @ £8.99 per set.

If you do have a problem, you can simply return them. Or ask your plumber to supply at say £10.00 per set (including diesel)

 

[Essex Fitters]

Ohh they have gone up in price now 9.49

http://www.*************/prods/36326/Plumbing/Radiator-Valves/White-15mm-Angled-TRV-and-Lockshield

 

[villa_tom]

I get bog standard honeywell from plumb centre for 5 pound-odd. Could you not just use these.

 

[Essex Fitters]

I get bog standard honeywell from plumb centre for 5 pound-odd. Could you not just use these.

Good price, just want this guy to go to retailer on high street rather than ebay. Saving a few pounds aint worth the wait and if the product it self fails, I very much doubt Mr Smith sitting at home on his laptop will take responsibility

 

[rthirlby]

Thanks for the links and suggestions, I will look into the plum centre ones if there is one near me. I have been speaking to the ebay seller and he isnt too far from me so I would be collecting. I am trying to find out if he is a business seller and if he can provide a proper receipt instead of going through ebay so I have a nice 5 year warranty on them.

I have a picture of my existing valves if you could double check there will be no problems.

 

[rthirlby]

Right the seller is a business not private so he can provide a proper receipt I just need help confirming they are definately the right ones for my system.

I did look at the plum centre website but I cant see any cheaper valves than the ones on ebay.


Also what tools will I need to fit the TRVs?

I think I need the following
Water Pump pliers
Adjustable wrench
Possibly an allen key?
PTFE Tape


I read somewhere about sealing paste to put on the radiator threads is this right, can anyone recomend a brand?

Thanks
Rich T

 

[villa_tom]

Any sealing paste really boss white jet blue etc. they are all the same to be honest.

 

[WHPES]

The valves you have at the moment are the Cosmos / Belmont type with the 3/4" dome coupling. Nearly all TRVs use 15mm tails.. You will need a radiator tail key to remove these in order to fit the new type tails into your radiator (plenty of PTFE tape round the threads or as I prefer use hemp and paste (eg boss white)). Put some PTFE round the olives.

Your existing valve has a drain cock so you also need a new drain cock somewhere on the pipework or replace the lockshields with drain cock types.

You will need to get the old nuts and olves off the piepwork without damaging it - will need some careful work with junior hacksaw.

WHen you reassemble you will need 15-10mm reducing olives for each valve. Wrap some PTFE tape round the olives and mating surfaces on these reducers to ensure a good fit and like another poster has said do not overtighten or you will crumple the 10mm pipe.

Another thing to watch is make sure the TRVs go on the correct way round. Some don't work properly if the water is flowing in the wrong direction through them.

 

[rthirlby]

Excellent reply thanks for that. So much so its scared me off doing the job myself lol.

My gas-man is going to do them for me free of charge and he will source valves for me.

Thanks to everyone for the help though, much appreciated.