Do not want to drain down central heating system

[boaz]

Greetings people,
After quite a lot of years, my Good Lady has now decided the bathroom does not get warm enough, and suggested replacing a large chrome towel rail ( 250 watt output ) for a radiator - don't you just love her ?.
Have found a rad that will give 1500 watts output, but the system will require a drain down as there are not isolation valves fitted to the supply pipes in the loft ( a bungalow so not great pressure from header tank ).
Installation:- Worcester boiler, fully pumped, expansion tank fitted as it is an open system, with rads and HW cylinder.
Question : If I sealed the expansion pipe end into the expansion tank with a push on end stop, and the outlet from the expansion tank, which has a gate valve already fitted, would it give a large enough vacuum to hold the water in the pipes when the towel rail is removed - this thought is going back to school days when the science teacher showed us that when a pipe was filled with water, if no air could enter the top then no water would be released at the bottom - however, this may not hold up in this situation. Any advice and thoughts would be most appreciated.
Kind Regards,
boaz

 

[kris]

Yeh that's what I would do. Make sure there well plugged and heating is all off . Shut towel rail valves and remove by emptying into tub. Once the TR is off I'd open one of the valves slowly n let it run into a bucket until it stops. Hang your new rad and put your pipes down under floor ready so it's just a case of cutting and joining. No sense cutting the heating pipe if rads no hung just incase the blank inside tank doesn't take the suction . You actually get rad valve changing kits for this particular job..... good luck mate

 

[tamz]

Have found a rad that will give 1500 watts output

What size bathroom do you have or are you turning it into a sauna?

 

[steadyon]

If I were you I'd first check that the old towel rail is actually on the radiator circuit. It used to be common for them to be fitted onto the hot water circuit, and some of the large diameter chromed tube ones are actually brass or copper so fit to take domestic hot water. Mind you, if its chromed copper, the scrap value could be more than the cost of the new radiator!

 

[Ermintrude]

Or it might just be on primaries / grav tubes which is a lot more common?

 

[boaz]

Thank you for all of your replies.
To answer some of your questions.
If pub member is happy I will give a go.
Tamz, it is about 12ft x 10ft plus the airing cupboard.
Stradyon, it is on the c/h side, as the hot water is on all the time, in the summer and the towel rail stays cold.
Thanks again to all of your help,
Kind regards,
Boaz

 

[happyflyer]

You are a very brave man if you even try bunging as its called, if you think your Doris is a pain now you will when you are decorating the ceiling below the bathroom, even after the plasterer
has put back up the ceiling, drain the dam think down, bunging is for people who don't need to ask how to do it in the first place.

I have been in the job 55 and I would drain it, anyway gives you a change to see what crap in in there:

PS are the rad centres the same as the old towel rail, if not you need to sit on the loo whilst you are doing the job.

 

[boaz]

Will give it a go. Thank you

 

[Ermintrude]

I know Dorris she's always complaining

 

[Loki]

Just make sure u bung the cold feed well I.e get a good seal around the outlet and don't assume the gate valve will hold a vacuum. I use it for changing the odd rad valve but never used it in alterations to a system.

 

[stevetheplumber]

You are a very brave man if you even try bunging as its called, if you think your Doris is a pain now you will when you are decorating the ceiling below the bathroom, even after the plasterer
has put back up the ceiling, drain the dam think down, bunging is for people who don't need to ask how to do it in the first place.

I have been in the job 55 and I would drain it, anyway gives you a change to see what crap in in there:

PS are the rad centres the same as the old towel rail, if not you need to sit on the loo whilst you are doing the job.

no ceiling below its a bungalow i would bung it and stick a couple of gatevalves below the floor assuming the pipework is below floor or stick them in the loft if its on drops

 

[Hardy1993]

I would agree with happy flyer, its just not worth it. Especially it those gate valves are old and arent shutting of properly!

 

[happyflyer]

Just make sure u bung the cold feed well I.e get a good seal around the outlet and don't assume the gate valve will hold a vacuum. I use it for changing the odd rad valve but never used it in alterations to a system.

I agree if it's swap like for like, still what in a drain down

 

[boaz]

no ceiling below its a bungalow i would bung it and stick a couple of gatevalves below the floor assuming the pipework is below floor or stick them in the loft if its on drops

Thanks, will do that, then I can nip out for a pint !!. In your opinion, would it be better to use ball valves as opposed to gate ?