2 Radiators cool and some others warm - pump ??

I also have problems with radiators not getting hot enough and the cylinder doesn't get up to the right water temperature even after being on for nearly 3 hours. (How long should a cylinder take to heat from cold?)

I am having difficulty getting any local heating engineers in so considering BG though I have read bad reports about them.

Could be the pump, could be thermo. rad valves (though that wouldn't affect the cyclinder water), could be sludge (we have a microbore system but it has inhibitor in), could be the pump, could be the boiler (Potterton PrimaF). One local heating chap I spoke to (who hasn't phoned back as promised) said it was risky doing a power flush on microbore systems and that they put some chemical in and leave it for a while and then drained it out and flushed through. Does that sound right? The pipes are under solid floors so I don't want to risk any bursts.

I have tried bleeding the rads but they are hotter at the top than the bottom and had no air in them. The boiler seems to be on for about a minute and then off for 4, or that was the case when I checked during the very cold spell.

Advice would be much appreciated.

It sounds your problems are the same I had.

First thoughts by technician was an air lock in the pipes somewhere. He started bleeding one radiator then decided to renew the pump. On removal of the pump found where there should have been something like a 20mm passage through the pump, I had only 5mm through the crusted rust etc. Since then the system is OK.

As for the power flush he said it takes 4 hrs to do with a machine with an cleaning agent then finishing off with a clean flush and finally fill with an rust inhibitor in the header tank. But as mine are 15mm pipework I am unsure your micro pipework.

If it is microbore, it would be difficult and not very effective to powerflush.

Go for the cleaning chemical, but have a System Filter added to trap the circulating particles as they are loosened by the chemical, and get the installer to show you how to empty out the trapped sludge. Chances are you will be amazed by how much it traps. Empty it at least weekly at first, then double the period each time there is no more than a smear, until eventually it only needs emptying yearly.

The filter will cost about £100 plus fitting. It should be fitted on the large return pipe close to the boiler.

Thanks for replies. I presume you mean a Magnaclean, which I had had in mind. Does the system still need an inhibitor? And do you think I should call in BG?

Are you fond of DIY plumbing? If not ask neighbours and friends who they trust and recommend locally.

I/m certainly not planning to do anything myself. As I said, I've drawn a blank with all the locals; they say they are all too busy if they get back to me at all. None of the neighbours has anyone they can particularly recommend but I have tried all the names mentioned, which is why I was wondering about BG.

if not too urgent, their workload will drop dramatically when the weather warms up and householders lose interest in their heating systems.

It's a good sign if a local person with a good reputation is busy.

I'm not clear who did the installation. Was it BG or someone else?

Not sure who put it in as it was done before we moved in. My cleaner thought it was one of those I phoned but it didn't seem to ring any bells with them. Certainly wouldn't have been BG as it was done when the property was extended when a completely separate system was put in for the new bit which was about as big as the original bit.