Cold Radiator After Removing One To Decorate

[coolertech]

Hi Everyone, I've taken to ask as I'm at my wits end now after reading loads of webpages and differing forums.

Basically, I took a radiator off in my spare bedroom whilst I decorated, I shut off the themostatic valve and locksheld valve whilst it was removed (cant remember if I used the central heating or not with it removed)

Anyway, I put the radiator back on after decorating and reversed what I did from when I took it off, I turned on the heating system and began to bleed it, whilst doing so I noticed that the radiator at the top of my stairs is stone cold (so are the pipes going to it).

I bled every radiator in my house (3 Downstairs, 6 Upstairs in total) but nothing I seem to do is helping, it's still stone cold, also the radiator in the living room is taking ages to warm up, where as the one at the bottom of the stairs gets very hot.

I've tried adjusting Locksheld valves, bleeding all radiators, adjusting all the thermostatic valves to max, but feels like I'm getting nowhere.

I'm not too well up with central heating systems, all I know is :

There is a Combi Boiler in the kitchen, along with a large tank in the back bedroom, there's also a terracotta coloured large plastic looking valve near the tank with a very large silver screw on it and a white electrical wire going into it, the screw is turned to off and when I try to turn it sounds like a pump, there is also 22mm pipe being fed in/out of it.

Not sure if I need to top anything up, or if the system is sealed or not.

Anyone any ideas?

Thanks

Pete

 

[seco services]

this will be your pump.

bleed the rads with the system off not on.
you say the other ones gone cold, are they all cold upstairs ?
check the f/e tank is loft has water in.

 

[coolertech]

Hi Seco, thanks for your reply

Ok Answer to your questions, yes there is a cold tank in the loft, I think this feeds the hot water system as I recently replaced the ball valve in that, with regards to the upstairs radiators, it's just one that stays cold, all the rest are either hot or warm, and yes that is the pump that is located in my back upstairs room.

Off your advice I've tried to bleed the rad's this morning whilst cold, there was a little air in the stone cold one but no water came out when the air stopped, also tried on the rest of the house rad's, a couple did nothing and the rest just dripped water out slowly.

Turned the CE back on an hour ago and the one in question is still cold :/

Anything else I could try?

 

[jackecole]

try bleeding the highest level rads - any water coming out of them? could be a blocked cold feed. or some air in the system somewhere - try turning the trv/manual valve not lockshield off on all hot rads and leave the cold one trv open

 

[coolertech]

try bleeding the highest level rads - any water coming out of them? could be a blocked cold feed. or some air in the system somewhere - try turning the trv/manual valve not lockshield off on all hot rads and leave the cold one trv open

Hi There, tried everything you said when I got home from work tonight, I tired bleeding all the rads again just before I turned all the thermo valves to off.

Still no luck, I've got water coming out of all the upstairs rads at the top, even the cold one, there are two rads hotter than the rest, the one at the bottom of the stairs and the one in the kitchen, all the rest apart from the cold one are warm to hot.

I too think there is air in the system, trouble is I don't know what to do next, as I mentioned in my past post there is a valve pump with a screw on it which is turned to off, I've tried turning it to open and it runs for about 2 mins then stops, doesn't make any difference to the cold rad though.

Another thing that Is sat right above the main hot water tank in the back bedroom is a red cylinder with a pressure gauge on it, the gauge is reading zero, there's a few other bits and bobs around the tank valve wise, Ohh also there are these funny looking valves on the downstairs rads on the 15mm pipes at the bottom of the radiators, they are painted over but look like some kind of valve with little spout run offs, they look like they would require a larger square valve key to open them.

Anyone any more ideas

 

[seco services]

Another thing that Is sat right above the main hot water tank in the back bedroom is a red cylinder with a pressure gauge on it,

thats an expansion vessel. so yours is a sealed system not open vented.

the gauge is reading zero,

you need to repressure the system first.
next to the vessel will be a filling loop, if you open this it will let water in and the gauge will rise.
turn heating/hw off and repressurise the system to the gauge is about 1.5 bar.
then bleed rads but keep checking the gauge don't drop below about 0.75bar.
when all rads bled check gauge is about 1 1.5 bar and put heating on.

you won't get anywhere with the cold rads etc is the gauge is on zero.

Ohh also there are these funny looking valves on the downstairs rads on the 15mm pipes at the bottom of the radiators, they are painted over but look like some kind of valve with little spout run offs, they look like they would require a larger square valve key to open them.

Anyone any more ideas

they are only draincocks for draining the system.

 

[coolertech]

Hi Seco, thanks for all your advice

ok, done everything you said, as noted before the gauge was on zero, I turned the lever at the side of the vessel and the gauge went up, I stopped it at 1.5 bar, I started to re-bleed the rads, starting with the ones downstairs, all of them downstairs where fine and water coming out of them at a better rate than before might I add.

I made my way upstairs and the one I'm having problems with had a tiny little bit of air but not much, the rad that I'd taken off to decorate had a more air in it, again I bled it until water was spraying/coming out from it.

I did all the rest and looked at the gauge, it had gone down to 1 bar, I turned the lever and let more water in to 1.5bar again and turned on the heating system.

after a short while the some of the rads started to get warm, mainly the ones that where warm before, the problem rad (cold one) is still cold, when I feel the pipe below the cold rad it feels very slightly warm, but only slightly.

I've made sure all the thermo's are open and all the lockshield valves are too on each rad, also the pressure on the vessel has risen to just over 2bar!!, is this normal?? (i'm keeping my eye on it as there is a red mark on 3 bar that indicates too much pressure)


So far the cold rad is still cold, is there anything else that I could try?

Many thanks for your help with this, I'll get there in the end

 

[kevplumb]

check the pin is free on the trv

sounds like it may be stuck down

 

[coolertech]

check the pin is free on the trv

sounds like it may be stuck down

BINGO!!!



I was just as you type looking at that as it wasn't warm on the thermo side of the rad, I've just removed the thermo head and got some combi's on the valve pin and instant hot rad!

I'm going to let it warm for and hour, turn off then again re-bleed the rad's.

Thanks guys for all you help

So glad it's sorted

Pete

 

[seco services]

So glad it's sorted

Pete

so are we

 

[coolertech]

So glad it's sorted

Pete

so are we

haha

just one last question, is it normal for the vessel pressure gauge to rise when you put your central heating on, if so what's the acceptable rate?

Cheer

 

[kevplumb]

yes its normal

the rate depends on the system size and the vessel precharge

 

[coolertech]

yes its normal

the rate depends on the system size and the vessel precharge

ok thanks very much