Can you drain underfloor heating pipes?

[Michl]

I want to repair a section of 8mm microbore heating pipe that got a nick when removing floorboards... This pipe is below floor level and there is no lower outlet to enable me to drain it (ie it's below all the radiators) before I cut out the nicked section and fit a compression fitting. Is there a smart way to drain this? Assuming valves work on radiators and I've turned them all off at both ends I don't expect there'll be much water to catch but was wondering if there was another way?

 

[Richardthe3rd]

I want to repair a section of 8mm microbore heating pipe that got a nick when removing floorboards... This pipe is below floor level and there is no lower outlet to enable me to drain it (ie it's below all the radiators) before I cut out the nicked section and fit a compression fitting. Is there a smart way to drain this? Assuming valves work on radiators and I've turned them all off at both ends I don't expect there'll be much water to catch but was wondering if there was another way?

If it's under your first floor then I suggest you get one or two containers to hand. However, if it's under a suspended ground floor, then I'd just let it run into your house solum.

Do you have a vented or sealed system??

 

[Michl]

It's sealed - combi boiler. Can't let it run into floor

 

[45yearsagasman]

Release pressure and use a freezer kit is one option, or just work quickly and have everything prepared including some towels. A sealed system will not leak much if you ensure no air can get in, and that means the caps on any air release valves should be closed while the work is going on.

 

[Michl]

where is the pressure release valve on the boiler?

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• Michl
• 26 Jun 2014
• 1

 

[HERTS P&D]

Drain down then use a wet vac on the pipe work under the floor, wickes sell them for £30 and it hold 12 litres.

Andy

 

[Michl]

I can't drain down as there isn't an outlet in the system other than the radiators (which I will turn off)

 

[ServiceNumpty]

Looks like a Vokera, with no PRV Outlet connected.

 

[ServiceNumpty]

Isolate the smallest rad downstairs, empty the rad of water into a baking tray or h/d bin liner, then connect a hose to one of the valves, open the valve and drain down, once drained you will only have a few litres of water in the downstairs pipe work.

 

[Michl]

it is a Vokera... Would fitting a PRV to it be a straightforward task?

I can't drain down - there is no lower outlet. Everything is on the same floor, rads are higher than the pipe work that supplies them...

 

[Agile]

I would use my air compressor to blow out the water!

Then I would fill the nick with solder but WITHOUT cutting the tube!

Tony

 

[Richardthe3rd]

where is the pressure release valve on the boiler?

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• Michl
• 26 Jun 2014
• 1

Cowboy alert, cowboy alert!!!! PTFE on compression fittings!!!

I'd not touch it with a barge pole with fittings like that & no PRV pipe!!

Get someone in. If you can get a good guy in Aberdeen??

 

[mfarrow]

To be fair to the 'cowboy' I can't actually see any PTFE on the threads, he was just a bit generous on the olives. PRV not being present would be more cause for concern though.

 

[Michl]

I think the PTFE is on the olives not the threads. Fitting a PRV is not easy?

 

[Richardthe3rd]

To be fair to the 'cowboy' I can't actually see any PTFE on the threads, he was just a bit generous on the olives. PRV not being present would be more cause for concern though.

That's just as bad, it should only be Boss White used on olives. PTFE on compression olives is poor workmanship. A smear of (joint paste) Boss White on olives is all that's required. Tightening the fittings with dry olives or PTFE round them is not the way to do it.