changing trvs

[novice1]

Have had a leak from a valve causing big cost for carpets etc (only part covered by insurance). Plumber said replace all trvs as they are 15 years old. Quoted about £500 plus valves. Fairly modern 15m system.
Questions:
1 - Do the valves tend to fail together, i.e is it wise to replace the lot now as I have to drain the whole system down?
2 - what is the way to do it? Is it turn off the outlet to the tank in loft, turn off CH boiler, open valves on all radiators (and boiler?) and drain from bottom point, replace trvs from top down, add fernox or equiv to header tank and refill slowly checking for leaks from bottom up?
3 - Do I need to do anything with the boiler?
4 - Any other tips on trv choices etc?
Any help gratefully received

 

[newbie1]

how many valves

 

[novice1]

twelve valves

 

[newbie1]

twelve valves means rather than mess around in future then change all at once as system will be drained anyway
boiler off or clock off isolate feed tank and drain then just replace each valve prob only days work though good trvs about 20quid less flash about 5-8 quid each

 

[novice1]

Thanks Newbie, very helpful.

 

[smoggs03]

stick some inhibitor in your header tank too!!when filling back up. oh and check header tank for debris before draining/ filling or a blockage is imminent

 

[novice1]

Thanks smoggs, will do.

 

[willing2learn]

Hi, a lot of the cost will depend on whether any of the pipework will have to be modified. This can turn a relatively straight forward job into a longer one

 

[novice1]

No. it's very straightfoward, modern house with standard pipework and easily accessible trvs. I'm weighing up whether to do it myself or to use a plumber. second estimate next week will help me decide!

 

[NickH]

Even "standard" pipework, whatever that is, can be a problem if you have no movement on it, like when its buried tightly in the concrete floor. Having said that, £500 labour seems possibly a bit steep.