Changing TRV's

[JimmyPlumber77]

Hi Guys
Bit new to all this but was hoping for a bit of help/advice please?
Whats the best procedure for changing TRVs like drain down, time & cost and do you use aids, like freezer packs or 'Aquavac' or similar?
Any help would be great

 

[GQuigley67]

Depends on type of system but I usually perform a chemical flush while I'm at it and refill with inhibitor

 

[JimmyPlumber77]

thanks
Primarily pressurised systems, how long would it normally take? And is there much cost in doing so? Or is that relative to what procedure you take? Ta.

 

[GQuigley67]

i would usually allow 20 minutes per radiator and some time for other activities, a 5 rad system won't take as long as a 13 rad system, so you work out how long it will take and x's that by your hourly rate.

 

[Best]

If sealed system I usually just take the pressure off the system and replace each valve.
Turn off any auto vents.
Then the only water that you need to worry about is from rad tail - just stuff a rag into it.
I only ever had a couple of times this went bad. Once when an old diaphragm in a gas boiler failed and the other job was one of the valves at a gas boiler wall kit leaked and gas engineers had to fix

 

[REDSAW]

couple of towels and just snatch them

 

[Jay The Plumber]

depends if the rads are fed from tails below the floor or drops from above..
without draining down you can get a fair bit of water coming out of a drop from above so I usually take no chances, drain down and have an aqua vac on hand when I do the changeover.
I usually have a waterproof mat or dust sheet down too