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View Full Version : Help needed with central heating plz



Timoweb
08-02-2007, 08:33 PM
I have had a combi boiler fitted about two years ago and now two of the rads are luke warm and not getting hot.

A friend told me to drain my system. I have done this tonight and now the luke warm ones are cold, stone cold. 4 others hot 1 warm 2 cold. I have bleed them all twice and cant find any air in system. Its a presure system runs at 1.5 bar.

Please help me its frezing :snow:.

nobby
08-02-2007, 08:49 PM
Was the combi-boiler fitted on an existing system?

The problem could be a blockage, either sludge in the system or a airlock in a pipe. If you've drained the system down fully then it's probably not an airlock.

If it's sludge then you can buy a treatment from most DIY shops / builder merchants which will halp clear it out. You leave it in the system for up to a week and it helps disolve the sludge (i've used it quite successfuly).

If the sludge build-up is too bad then it may need a powerflush - prob best done by a plumber, takes him half a day and is quite expensive. Would try the treatment first though as it's quite a bit cheaper.

Timoweb
08-02-2007, 09:02 PM
Its a complete new system. Have stuck a bottle off that system stuff in tonight what a pain is too and a mess. Guess fingers crossed it works if not al ring a plumber next week.

Hitman
08-02-2007, 09:43 PM
Does your new system have thermostatic valves on the rads?

I have got trouble on one of my rads now and im sure its the valve.

had trouble with them before.....are the pipes that lead to the rad very hot?
Worth checking out

Timoweb
08-02-2007, 09:51 PM
No thermostatic valves just normal turn ones. Was thinking about putting thermostatic valves on for a while and i have noticed the design of them has totally changed over the past 6 months (an the price). The pipes to the dead ones are stone cold.

Jango
09-02-2007, 08:50 AM
Hiya Timo, I have the same system as you, the way you describe it. I've messed around tons of time draining, filling over the last year and replacing the rads. I'm no plumber but I'm not shy of sorting the system. I would say that it has to be air in your system, I would go through the whole process of bleeding every rad in the house again while the heating is on. If that doesn't work, drain it off again and start over. A combi for a novice (me not you) is the easiest system to work on.

Timoweb
09-02-2007, 10:23 AM
Think its one of two problems.

Air in the pipes or the pump has had it.

Managed to get one off the rads workin this morning after re-bleeding again this morning. Will try this weekend and see if i can totally illminate all air out off system. If its still not working will get a plumber to look at the pump.:(

Jango
09-02-2007, 11:35 AM
Hiya Timo,

If the other rads are heating up as you said they were, then I couldn't see how that could be the pump. Me thinks, if the pump wasn't working then none of the rads would heat up. I've always found when I take them off to decorate and then put em back on, I open all the valves fully (not the key). Go to the boiler and start to fill up with water till it gets to the pressure mark, go to each rad and let the air out (still without switching the heating on). Go back to the boiler as the pressure will have dropped, fill up again to the press level and again go around each rad to let the air out. Any plumber reading this may think all around the houses, but it works everytime for me. Basically, air is a bas****d in central heating...hope you get it working mate and don't call a plumber.

Timoweb
09-02-2007, 08:02 PM
Heating update, glad to say all back up and running. One is still not as hot as all the others but seems to be getting better.

Bleed of tonight and the water colour has totally change from an off yellow to a thick grey. The addative bottle i put in was clear. Must have done something, still think there is a little air or block in the pipes to the luke warm one because the more i drain the better it is slightly.

Thanks for your help guys.

nobby
09-02-2007, 09:36 PM
Heating update, glad to say all back up and running. One is still not as hot as all the others but seems to be getting better.

Bleed of tonight and the water colour has totally change from an off yellow to a thick grey. The addative bottle i put in was clear. Must have done something, still think there is a little air or block in the pipes to the luke warm one because the more i drain the better it is slightly.

Thanks for your help guys.

Well done m8 - glad to hear things have improved. You'll have to read the instructions to be sure but I think you can leave the additive in your system for up to a week. If the water was that bad when you bled off then is it worth another go?

Either way, thanks for letting us know

satman
09-02-2007, 10:24 PM
hehe

i reckon this thread should be a 'sticky'

Timoweb
10-02-2007, 11:30 AM
Well done m8 - glad to hear things have improved. You'll have to read the instructions to be sure but I think you can leave the additive in your system for up to a week. If the water was that bad when you bled off then is it worth another go?

Either way, thanks for letting us know
On the bottle it says leave in system so i am, at least untill the cold spell ends (think al drain system in summer and put fresh water and running additive in). Its Sentinel X100 buy the way and must be working because the one that has been luke warm for months is toasty hot this morning. All rads now hot, wow i fixed it lol. I would recomend that Sentinel stuff a bit expensive i thought but it worked after only 12 hours so well worth it.

berley
10-02-2007, 11:33 AM
aww clever you timo glad you got it all sorted out in the end :)

might try that stuff in my system cos one of the upstairs one does not not heat up great

nobby
10-02-2007, 01:16 PM
On the bottle it says leave in system so i am, at least untill the cold spell ends (think al drain system in summer and put fresh water and running additive in). Its Sentinel X100 buy the way and must be working because the one that has been luke warm for months is toasty hot this morning. All rads now hot, wow i fixed it lol. I would recomend that Sentinel stuff a bit expensive i thought but it worked after only 12 hours so well worth it.

Yes it's good stuff! Not expensive in comparison to calling a plumber out!!

lfckev
11-02-2007, 01:36 AM
hi m8 try this all the radiators that r getting hot turn off when the ones that r cold now warm up turn others back on

RosIrl
14-02-2007, 02:37 PM
Hi all,

Just a hint. If you are getting sludge in the system in the first place it is due to badly balanced and leaking in th system. The flow to each rad and out of each rad needs to be regulated depending on how far from the pump it is the farther away the more open should be your return valve. This allows for more draw through the rad and stops sludge from settling in the system. The main reason sludge forms in the first place is due to a leak somewhere in the system.

Timoweb
14-02-2007, 04:17 PM
Hi all,

Just a hint. If you are getting sludge in the system in the first place it is due to badly balanced and leaking in th system. The flow to each rad and out of each rad needs to be regulated depending on how far from the pump it is the farther away the more open should be your return valve. This allows for more draw through the rad and stops sludge from settling in the system. The main reason sludge forms in the first place is due to a leak somewhere in the system.
I did have a small leak on one rad for about 4 months, replaced it with a new one before xmas. Perhaps this didn't help and started the build up! Fixed now :thumbup2:.