Plumbing question for the experts

AMGeed

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My daughter recently moved into her first owned property and is renovating room by room. She has a GF flat and wants to drain down the CH system to be able to remove radiators as required now the heating is no longer necessary.
On my own CH, I have a tank in the loft where I just support the ballc0ck to stop the system refilling once the rads have been drained.
She doesn't have a loft tank, just a Gloworm boiler with attached timer and shut off valves on most of the piping in the boiler cupboard.

What do I need to do to stop the rads refilling short of turning off the valves to each rad ?(I don't find they are that good at completely stopping the water on older valves)

I still want to keep the water supply available in the kitchen/bathroom for obvious reasons.
 

MCFastybloke

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Is it a Combi boiler, in that when you turn on the tap does it come to life and hotwater follows shortly after?

Why cant you just shut the valves and drain the rad off by undoing the nut onto the rad tail, maintaining the integrity of the rest of the system? im currently doing this room to room.
 
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AMGeed

AMGeed

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I don't know and that is something to find out. I suspect it is a combi boiler as I see no seperate progarmmer for HW and CH.

I once made a silly mistake undoing a rad tail nut which resulted in mayhem in the kitchen. From then on I drain down the whole system before removing rads. (Expensive with new Fernox I know).
This may be the way to proceed though.


Edit............Its a Gloworm Combi boiler.
 
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m80

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For gravity fed there needs to be a header tank. Mounted higher than the system to supply by gravity.
A sealed system will use the same feed that feeds the cold water into the boiler for the hot water (combi).

Either way isolating a radiator via the valves 'should' be adequate. Dependant on the integrity of the valves.

Turn off,
release from rad via the hex nut,
catch the contents of the rad,
pull clear 'a little' and monitor while having a cuppa.
If the valve leaks screw it back onto the rad.

When I'm sure dripping has ceased I put white tissue under any suspect point, it's a good tell tale.


I assume at some point you will be breaking into the pipe work, that'll need a system drain down.
 
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AMGeed

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I assume at some point you will be breaking into the pipe work, that'll need a system drain down.

Maybe not me, but at some point the boiler was moved and there are a 22mm and a 15mm copper piped capped off inside the old cupboard about 6 inches above floor level.
Today I pulled down the cupboard so yes, those pipes will need to be cut off and capped below the floorboards. I assume they could be cold water and gas feed to the boilerwhen it was in its old position.

The valves look faily ancient which was another reason for preferring to drain down all the rads. But I'll probably take the opportunity to replace them as each rad is removed.
The things we do for our kids eh?:cool:
 

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As said Roger, no need to drain the system. Not ideal anyhow given you wish to keep the hot water up and running.
Remove one rad at a time, after turning off valves. TRV’s do sometimes pass water (depending on age and maintenance of system). The Lockshield Valves are usually fine

Best thing is to buy some 1/2“ & 3/4” Female caps (online) to screw onto valves after rad is removed. This will ensure no water leakages.
 

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Well given you need to cap off gas and water pipes I would get a plummer involved,get the floor boards up,and get a teach in for that boiler,they all have a filling loop and normally two inline valves on the water so that you open the valve at the boiler and then the water valve and refill the boiler after you have drained down the system,most boilers have a small gauge and need about 2 bar of pressure to operate.
 

MCFastybloke

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See rad


Turn this to zero


Remove this cap and turn valve off


Open this, use kitchen roll


IF is stops squirting then valves are off

Now you can get set up for taking rad off, thick dust sheet and something to catch water position receptacle under one valve and open this STEADY



Mucky water will now come out with air going in the bleeder to replace it in the rad

Wait a bit, then loosen other nut with receptacle


Now the tricky bit, you need to ease of the valve and get your thumb over the end sharpish at both ends, can be a two person job, carry it outside or to the toilet to drain the black residual water out, git it a flush when before you refit and bod a corrosion inhib in the last one you do.
 

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See rad


Turn this to zero


Remove this cap and turn valve off


Open this, use kitchen roll


IF is stops squirting then valves are off

Now you can get set up for taking rad off, thick dust sheet and something to catch water position receptacle under one valve and open this STEADY



Mucky water will now come out with air going in the bleeder to replace it in the rad

Wait a bit, then loosen other nut with receptacle


Now the tricky bit, you need to ease of the valve and get your thumb over the end sharpish at both ends, can be a two person job, carry it outside or to the toilet to drain the black residual water out, git it a flush when before you refit and bod a corrosion inhib in the last one you do.
Isn’t that a thermostatic head?
 
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AMGeed

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^It is. A standard rad valve is just screwed clockwise until closed as I know you know :cool:
 
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AMGeed

AMGeed

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See rad


Turn this to zero


Remove this cap and turn valve off


Open this, use kitchen roll


IF is stops squirting then valves are off

Now you can get set up for taking rad off, thick dust sheet and something to catch water position receptacle under one valve and open this STEADY



Mucky water will now come out with air going in the bleeder to replace it in the rad

Wait a bit, then loosen other nut with receptacle


Now the tricky bit, you need to ease of the valve and get your thumb over the end sharpish at both ends, can be a two person job, carry it outside or to the toilet to drain the black residual water out, git it a flush when before you refit and bod a corrosion inhib in the last one you do.

You have just described my normal, and previous course of action.
One time I didn't support the body of the valve whilst undoing the nut and the valve twisted to the side and broke the seal on the olive. Much fun ensued:wallbash:
 

m80

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Anything that affects the integrity of gas needs a Gas Safe chappy.
The 22mm can be for the heating flow and return also.

I'm pretty sure you will need approx 1/2 bar in the heating for the boiler to fire up and provide hot water.
You can isolate the flow and return at the boiler and then drain down the system from a rad, but remember to open a bleed up stairs somewhere or it will hold on a partial vacuum and drip forever.
 

Happytalk73

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See rad


Turn this to zero


Remove this cap and turn valve off


Open this, use kitchen roll


IF is stops squirting then valves are off

Now you can get set up for taking rad off, thick dust sheet and something to catch water position receptacle under one valve and open this STEADY



Mucky water will now come out with air going in the bleeder to replace it in the rad

Wait a bit, then loosen other nut with receptacle


Now the tricky bit, you need to ease of the valve and get your thumb over the end sharpish at both ends, can be a two person job, carry it outside or to the toilet to drain the black residual water out, git it a flush when before you refit and bod a corrosion inhib in the last one you do.

I’d hoped you’d have removed rad and taken pics for Roger. Plain selfish. 😂
 

MCFastybloke

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Not needed on the majority of valves as zero is zero, you are correct it is a possibility of leak by, a 3/4 female cap from Screwfix will give belt and braces if it is a worry and no cap can be found. Not had an issue of this type ever. I have inadvertently turned it on with a careless foot.


If you don’t put the decorators caps on TRV or cap the pipe let’s hope the temp doesn’t drop!!
 

Darrell

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Not needed on the majority of valves as zero is zero, you are correct it is a possibility of leak by, a 3/4 female cap from Screwfix will give belt and braces if it is a worry and no cap can be found. Not had an issue of this type ever. I have inadvertently turned it on with a careless foot.
Won’t it open up if the temp drops?
 

MCFastybloke

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I dont categorically know. i have never thought it through, i will go take a head off and look


I took a TRV head off and when its at zero you can push the rod up/open, still cant say if the thermo matter could pull it up that far,. So i would say yes it is a possibility but i would thin it would have to be right cold
 

Darrell

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not if turned off completely passed the * mark.
I personally wouldn’t risk it.

The TRV heads can play up with age so I have a little collection of caps that I use to do the job properly. At least with a cap you know that it’s off and will stay off.
Always better to be safe than sorry.
 

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not if turned off completely passed the * mark.
Yes it would, all TV have frost protection so do not close fully off, need to either put on the decorators cap or cap the fitting where the rad has been removed.
Much better to drain the system. In my opinion.
 

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