Plumbing question for the experts

Fununcle

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Trv's not tv
 

Happytalk73

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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.

Our TRV’s go from:

Off
* Frost
1
2
3
4
5

that’s what I was saying.
 
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AMGeed

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There are no TRV's fitted anyway so no need to worry about that.

I'll be carefully removing the rad by undoing the valve nuts and capping the ends. Tilt the rad up and empty contents into a bucket.
Thanks all.:thumb:
 

knighterrant

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I’ve replaced a couple of radiators in my house when I had a Glowworm combi boiler. Rather than drain down the whole system I shut off both sides of all the radiators above and on the same level as the one I was replacing so I only had to drain off what was in the pipe work. Fortunately all our CH uses plastic small bore pipes so not much to drain off (at the point where I removed the rad). On both replacements I had to cut and reposition the pipes, which I did with no problem and no more than a tiny bit of water leakage.
 

MCFastybloke

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There are no TRV's fitted anyway so no need to worry about that.

I'll be carefully removing the rad by undoing the valve nuts and capping the ends. Tilt the rad up and empty contents into a bucket.
Thanks all.:thumb:


If they are of an age a few wraps of ptfe can help get a seal on the olive without resorting to massive torque.
 

190

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I recently drained my system down to move the radiator in a bathroom.

Here's my tip: if you have drain valves like this drain.jpg there will be a rubber washer in side drain washer.jpg which if the valve is of any age may well have perished. When you re-fill the system the valve may not seal and drip no matter how much you tighten it. Then you will have to drain the system again and replace the washer. Have a washer to hand and replace it after the first drain. You can guess how I come to be making this recommendation.
 

Darrell

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I recently drained my system down to move the radiator in a bathroom.

Here's my tip: if you have drain valves like this View attachment 95283 there will be a rubber washer in side View attachment 95284 which if the valve is of any age may well have perished. When you re-fill the system the valve may not seal and drip no matter how much you tighten it. Then you will have to drain the system again and replace the washer. Have a washer to hand and replace it after the first drain. You can guess how I come to be making this recommendation.
We’ve all been there fella!!
 
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AMGeed

AMGeed

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I recently drained my system down to move the radiator in a bathroom.

Here's my tip: if you have drain valves like this View attachment 95283 there will be a rubber washer in side View attachment 95284 which if the valve is of any age may well have perished. When you re-fill the system the valve may not seal and drip no matter how much you tighten it. Then you will have to drain the system again and replace the washer. Have a washer to hand and replace it after the first drain. You can guess how I come to be making this recommendation.

Yep, got that drain valve on my system and daughter has too. Thanks for the tip.
 

Peter103

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If you look under the boiler in the cupboard, you will see two 15 mm copp. pipes, one is hot water out the other is cold water in, turn the slotted screw 90 ° to hoizontal this will shut the cold water supply and the cold màin in via the filling loop, or their could be a similar valve on the filler,. Put a hose on the drain valve on the lowest rad and drain the system, fill it up cold to 1 bar, job done. Good luck.
 

knighterrant

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If you look under the boiler in the cupboard, you will see two 15 mm copp. pipes, one is hot water out the other is cold water in, turn the slotted screw 90 ° to hoizontal this will shut the cold water supply and the cold màin in via the filling loop, or their could be a similar valve on the filler,. Put a hose on the drain valve on the lowest rad and drain the system, fill it up cold to 1 bar, job done. Good luck.
I would add inhibitor after a full drain down.
 
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190

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2 more questions on radiators for the professionals

Every time I've replaced a radiator over the last few years the 1/2" BSP threads in the radiator have seemed too big for the valve stub and needed masses of ptfe tape to seal. I suspect this is a common problem and wonder how the professionals do it. Is the thicker gas spec ptfe tape a better bet or do you use a jointing compound.

I bought some new chrome valves for a towel rack and they don't seem to have adjustable glands so I assume an O ring seal has been used. How reliable are O ring seals in regular use. I don't want to have to drain the system to replace them.
 

Peter103

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2 more questions on radiators for the professionals

Every time I've replaced a radiator over the last few years the 1/2" BSP threads in the radiator have seemed too big for the valve stub and needed masses of ptfe tape to seal. I suspect this is a common problem and wonder how the professionals do it. Is the thicker gas spec ptfe tape a better bet or do you use a jointing compound.
No!!!use normal PTFE tape, if your fitting new half inch valves on an old rad the old female rad thread may appear loose/ floppy, just wind a few extra turns of PTFE on and fully tighten it will be good. You can use up to fourteen turns no matter. Do not use thicker gas PTFE tape or Boss white paste. Unless you are using hemp and paste. Your new towel valves if no gland nut could be ground in or have o ring either way it's ok. To balance the system when replaced fill and vent the rail, shut the flow side from the boiler open return valve on rad fully, light boiler let system heat up, when hot slowly open rad valve on flow, when you feel hot entering rad stop opening and vent rad till full, that's it. Never fully open both valves on towel rails or indeed any rad or you may find some rads don't heat. ie. the system becomes unbalanced. Good luck. Take your time you'll be ok. 👍💤
 

Peter103

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I still have most of my own teeth in good order lol. One other tip for any Non Plumbers on here. When refilling a drained system start venting with rad key from the lowest rad, and work your way up the building, when all full the boiler should either have an open vent for htng, and h/w, or if a Combi an automatic vent so, good. But don't forget the heating pump, if it's a Grundfoss or similar in the center of the main body is a large crosshead screw undo it, beneath is the pump spindle, use a thin screwdriver, (like an electrical ) push it into top of spindle and twiddle until spindle turns freely , you will hear/ see air bubbles and when it drips regularly replace big crosshead screw, turn on boiler electric s and fire up boiler let it run, see what's hot and what's not, any rads with cold spots at top, turn off boiler and vent with rad key. Never vent a heating system with boiler and pump running, let it cool ,vent the odd rad then fire it up, should be good. Here endeth the first lesson. "Just Do It" it'll be fine.👍
 

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