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looby · Joined: 03 Jun 2003 Posts: 2

Central Heating hasn't worked properly since we moved in in March Sad

Its a small 3 bedroomed detatched house (8 years old) with 5 single Rads upstairs and 4 downstairs.

When we turn the heating on, all the Rads upstairs work fine but there is no heat at all downstairs.Turn all the Rads off at the controller valves upstairs and all the Rads work ok downstairs. Hot Water works fine. This is the state of play right now.

So far this week we have changed the pump (The old one was full of small chippings and looked burnt out, it was also very noisy. We used it as an alarm clock it was that bad.) I also removed all the Rads and cleaned the gunge out and more small chippings ( There was a lot). We are at a total loss as to why this should be like this. If the Rads upstairs are hot, where does the hot water go to if not the downstairs Rads ???

What is there left to check ?

thescruff · Moderator Joined: 03 May 2003 Posts: 4751 Location: Bath

What is there left to check ?

Everthing, but first more info on the boiler make model, type of system, sealed or vented, are the pipes plastic, copper or steel, what size are the pipes, what is the pump and setting, has the system been power flushed, has the system been dosed with an inhibitor, are there any motorised valves and are they two or three port.

Explain the chippings, are they rust or scale or what.

That should do for 10 mins

thescruff Cool

looby · Joined: 03 Jun 2003 Posts: 2

Its a Myson Apollo 40S Boiler, on a conventional Vented System. The Pipes to the Rads are copper (15mm).
I have tried the new pump on all 4 settings and have now settled on No2 as I was worried about cavitation.I must admit, every few mins it does sound like air or something going through the pump, but I`m not sure.
The motorised valve is a 2 port if I am understanding what you are asking. Inlet and then it can go off in either of two directions.
Can you explain "Power Flushed" as well as "dosed with an nhibitor"?

The chippings look like Scale approx 4mm x 3mm thick.

Look forward to your reply

Thanks

Looby

I have just tried draining the system with the pump switched on. The header tank is full and filling up to compensate.I have the hose going into a bucket and there is a hell of a lot of air coming out. Stopped after 30 mins because still loads of air bubbles coming out.

While I was draining it, all the radiators upstairs and downstairs heated up. Then when I closed the drain off it went back to just the upstairs radiators being heated

thescruff · Moderator Joined: 03 May 2003 Posts: 4751 Location: Bath

One in and two out is a three port.

Power flush is what BG and the heating guys charge 400quid for,not bad for about 5hours work, it essentially cleans the muck out the system.

You can hire a machine from your local hire center connect it to your heating and follow the instructions ( more info if required ) all new systems have to be power flushed before they warrant the boiler.

Inhibitor is what you dose the system with when new and perodicaly afterwards to stop corrosion.

The chippings I'm not sure could be scale or corrosion.

Cavitation shouldn't be a problem, blowing over and sucking in air could be.

Can you email a sketch or jpeg of the system showing the pump, airing cupboard pipework layout, valve etc.

thescruff. Cool