Changing a radiator valve without draining the system...

[Paul Williams]

Hi there

I've got a seized up rad valve on an upstairs radiator (at the same height as the builer.

If i turn the CH system off and remove the valve, will this be OK? Or will i end up with water pouring out everywhere? My reasoning is that if there's no head of water,a nd no pump operating, there wont be any pressure.

Or am i way off beam here?

[burbeck]

hi paul, yes you are way off beam, in any kind of system this requires a drain down regards bob

[pauljwilliams]

I realise that the rad will need draining first, but thats easy enough. I was more concerned with the pressure of water in the exposed inlet pipe (which runs vertically up through the floorboard) creating a stream of uncontrolled water to flood out.....

[Grunff]

Is the valve at the bottom of the radiator (like on most rads)? If so, what do you think will happen to the water in the radiator?

[pauljwilliams]

What about using pipe freezing?

Basically, I'm confident enough to have no problem replacing a single rad valve, but draining and refilling the whole system makes me nervous....

[Grunff]

Yes, that is exactly what will happen.

[Grunff]

The risk there is that something will go wrong, and end up taking a lot longer than anticipated (and the frozen pipes will melt). This happens to everyone at some point, but is more likely if you're relatively new to plumbing.

Draining/refilling isn't as hard as you think, and is by far the safest approach.

[burbeck]

hi paul, i understand your feelings but the freezer way is realy only for the pros far safer as the other poster said to drain down, it is not all that difficult a task. what kind od system and boiler do u have ? regards bob

[pauljwilliams]

Heh - thats the million dollar question - i've only recently moved into the house, so i'm not totally sure. Its a combi boiler, but above and beyond that i dont know.

What distictions do i need to make, and how do i find out what sort of system i have?

Alternatively, how much is it likely ot cost to get a plumber out to do it?

[burbeck]

you have answered the question paul its a combi type system, these are straight foward to drain down the filling of the system is a bit more tricky nothing beyond you im sure though. try googling (uk) for it i'm sure there will be some straightfoward advice out there. as to your other question how much would a plumber want the answer is an arm and a leg, and an extra pound of flesh to boot. after all the are on here most of the time lol. regards bob

[Mike]

And while you're at it, take the opportunity to flush the system through properly with one of the flushing gunks to get all the years of accumulated crap in the system out.