Sealed System Radiator Replacement

[p_maidment78]

How do I replace a radiator on a sealed system? Should I try this? I am concerned that if I drain the system I will not be able to fill it properly.

 

[kevplumb]

1 drain the system
2remove old rad
3fit new rad
4if you get stuck POST
5wheres the problem?????

 

[p_maidment78]

I am happy to change the rad but I have not done this on a sealed system, is there a easy way to refill the system? I am doing this on my own so it looks like a lot of running about.

 

[breezer]

who said life was easy?

you should also try a search on filling loop, low pressure do this first then find where your filling loop is

 

[topgazza]

Just done this on mine. Turn both valves off, drain, remove, replace. As Kev said its easy. Replaced mine with towel rad which required additional pipes to reduce the width for the lovely chrome towel jobby. Turned it on, opened bleed valve and lots of hissing then water. Magic.

 

[chrisgarlick]

Hi

Sounds to me like you don't know where your filling loop valve is - ie, you've never had to refill or top up... ?? Somewhere on your system you will have a manual valve connecting your rising main to your central heating circuit - this is how you refill your system if you have drained it. It's a simple principle of introducing mains-pressure cold water to the circuit - obviously with air being vented through one or more rads. Same idea as a header tank in a vented system, only this injects directly from the mains water supply.

It shoud be somewhere on the return leg of your CH system. Look out for a spurious bit of pipework coming off the lockshield-side of a rad, disappearing somewhere. Trace it and you might well find the valve. Ideally it will be easily accessible but my valve(for example) is in the loft - not obvious at all. There ought to be a pressure gauge next to the valve, so you can see what pressure your system is running at.

As a minimum there will be one on your boiler if this really is a sealed system. You can't over-fill - the boiler should have a pressure release valve which will blow at somewhere around 1.5 bar - ie, if you over-pressurise, you will soon know. Do your work, make all good, open a bleed screw somewhere, find your valve, open it, pressurise to approx 1.5 bar as per whatever pressure gauges you have.

Good luck !

Kind Regards

 

[kevplumb]

will blow at 1.5 boll*ks

 

[chrisgarlick]

Not a terribly intelligent or constructive contribution there, kev.

Re-pressurised my own system today following moving 2 rads...boiler over-pressure valve blew at 2.1 bar. 1.5 or 2... who cares.? My point is that he shouldn't be afraid to drain and then re-pressurise his system... his main challenge is to find the filling loop.

In what way do you think your post helps our friend?

 

[breezer]

who cares.?

I do, giving out wrong information is not a good idea

 

[kevplumb]

if the prv blows at 2 bar it needs replacing

 

[DLaing]

Mine didn't blow at 3.5 bar after the nice man from BG left the filler loop open. Sadly the compression joints around the pump blew instead and flooded the attic room and my newly decorated bedroom below!