Advice draining CH system and fitting TRV

11 Sep 2007
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United Kingdom
Hi Guys, want to change the valves on my rads to TRV's

All rads are on one floor with the boiler (combi) sited in floor above.

There is a drain point on the boiler, flow and return go down into the floor space that the rads are on, then up out of floor into radiators.

There is no drain point on any of the rads :evil:

Any advice on how to drain system? I could always put a hose onto one of the valves and drain that way.

Any advice greatly appreciated
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Sounds to me like no other way but to improvise... maybe freeze one of the tailpipes and add a hose to it then when it unfreezes everything will drain down... but I'm sure there will be an expert along in a minute to give a really good method!
When you have drained down, remember TRVs can be of different size to lock sheild valves and may throw your pipe work out, also leave one of your rads without a TRV.
drain a rad and take it off the wall (small rad is better) connect hose to the rad valve (that is still attached to the pipe!!) with either a 1/2 or 3/4 connector and drain that way.
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Thanks, kind of guessed the pipe work would need altering a little!

My problem is the draining down, as in my original post, any suggestions?

Worried if I cant get enough water out, soldering to alter the pipework may be a problem :eek:
Any more thoughts or suggestions with this problem?

One radiator valve is leaking pretty bad and need to change it so thought of putting a TRV on, its leaking from the pipe up to valve so need to drain etc to fix...

As sods law commands I doubt the new valve will go straight on will need some alteration so if soldering would need to get pipes dry.......

As in my original post, boiler on floor above with a drain valve, all rads on floor below with no drain valves, pipework comes up from floor boards into valves.

Really hope you can advise :rolleyes:

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