Some radiators not heating-any advice welcome.

[Ashleyni]

Hi,
If anyone can anyone offer any advice -I would really appreciate it.

We had a wood burner installed back in September which linked into our heating system (we have oil). Right up until 2 days ago we had no problems apart from on the odd occasion we had steam in the roof space. Then 2 days ago we noticed the radiators weren't heating when we turned the heating on.

when we checked the tank in the roof space the insulation had melted into the tank and therefore the ballcock was stuck. We removed the plastic and the next day drained the heating system. On letting the system refill most of the radiators heated up apart from 3 these are spread throughout the bungalow 2 front bedrooms and a new one in the porch. We bleed the 3 which were not heating and water is coming out but still no heat.

A friend said that the reason the steam was in the roofspace and the insulation jacket may have melted is that we had the wood burner pump and central oil heating pump running concurrently -thankfully this was on a very rare occasion. I didn't realise there was a problem running both!!!!

So I was wondering if anyone had any thoughts on why some radiators wouldn't be heating but others are and water is coming out when we bleed them? We have a tank with a ballcock in the loft (f&e system I think it's called). So I can't adjust the pressure using a gauge like some websites have suggested.

Any help would be really appreciated.

 

[Hufty]

Try turning off all the rads but one working one and one non-working one to encourage pumped circulation round the non-working one. If that doesn't work more or less immediately, I usually turn off both valves, remove the whole 1/2" bleed plug then use a spare radiator tail and a hose pipe to draw off half a bucket of water with one valve open and half a bucket with the other valve open. Might work just using the bleed but you'll be there a while! Wouldn't try this if you're not confident or if you have cream carpets.

BTW make sure the header tank is rated to take the temperature, and that the base is completely supported by a flat surface. If it's a plastic tank on two bits of wood the nightmare scenario is that the base collapses in when the plastic is hot. Pipework should be metal - pushfit pipe and fittings aren't rated high enough, metal ball valve not plastic, copper float if you're going for it.

And surely there is some sort of high limit pipe thermostat to cut the oil central heating when the wood burner pipes are above a certain temperature?

 

[Ashleyni]

Thanks for the quick response.

Just tried what you said and it is forced the heat to the three radiators however one of the radiators is only Luke warm plus it's cold at the bottom. Sounds like it may be sludge or something and the radiator will have to come off and be cleaned.

I am going to give the installed a call re your comments about tank etc just to confirm everything.

Any thoughts on the one radiator now being hot at the top and cold at the bottom please feel free to say.

Thanks again

 

[Hufty]

I would probably do what you've said and give that final radiator a blast through with a hose if it's easy to get off the wall and outside.

Two other things to check about your link-up system:
(1) is it designed to fail safe in a power cut? I.e. is there gravity circulation and some way of getting rid of heat from the woodburner if the pump stops and any motorised valves are closed?
(2) does the oil boiler heat the pipes going into the woodburner when the stove is not lit - this is a waste of oil as the heat ends up going up the flue.

Not saying there's anything wrong with your system - I've not seen it - but these are two classic design errors so I just mention them.