Overheat problem - Baxi Solo 3

[Malc C]

Dave, could I trouble you (or anyone else for that matter) on a further development.

After much fidling about last night I managed to get one of the downstairs rads in the living room luke warm, the downstairs hallway rad red hot, upstairs bathroom rad red hot, and bedroom 1 and 2 rads were warm (comfortable) and bedroom 3 rad cold. The heating then shut down fro the night and we retired to bed.

This morning when the heating kicked in I was awoken by the sound of a single loud pipe bang as the motorised valve or pump kicked in. The heating ran for an hour and a half (its programmed time) and in that time the bathroom rad was red hot, as was bedroom 1, bedroom 2 was comfortable as was the downstairs hallway. Both the kitchen and the two rads in the living room were cold.

Could that pipe bang indicate that although the pump is working, there is indeed a blockage in the system ?

Comments please

Malc

 

[gas4you]

Could be a blockage, could be a massive air lock. Unfortunately only local investigation will find out.

As said turn off all rads except one and turn off dhw, shut by-pass valve and turn on. When that rad gets hot turn it off and move to next one etc etc. When and if all work then re-open by-pass by about 1/2 turn.

 

[Malc C]

Dave, thanks for your help,

I might try draining the system and re-fill, however I think that if it was down to an airlock I would of come across it when I tried bleading the rads. I can't work out why the pipes would be really hot one side of the valve, but the rad side it would be either warm through conductivity, or the rad would be stone cold. I freed up all the valves and none were stiff !

Thanks once again, If I still have issues I'll look for a local plumber to come and have a look

Malc

 

[Malc C]

What bypass valve ??

 

[gas4you]

Air locks can be in the pipe work, not the rads hence why bleeding the rads won't help.

Sounds like an airlock in the return somewhere.

 

[giblets]

Maybe the overheat thermostat has failed or gone out of calibration - not unknown.

 

[Malc C]

Thanks for the comment,

More experimentation today and I managed to get all the downstairs radiators warm (some more than others) and the bathroom still remained hot. In fact I set the thremostat in the hall to 23C and it reached this and cut the heating off as it should, although it did take a while for the house to heat up.

The boiler does still switch on for fairly short periods, so you might be right about the calibration, so I'll look out for a replacement PCB on the usual sources

Regards

Malcolm

 

[Malc C]

Well, with a lot of fiddling we've managed to get some heat in the lounge, but the system isn't working as well as it should. The pump is fine as I can feel the heat progressing through the pipes when I've opened all the valves on the rads. Anyway I digress from the reason for posting.

I obtained two quotes for installing 5 new rads and re-locating three of the existing ones that are only a couple of years old (and will be flushed prior to re-installing). There was a difference of £500 between them but both were around the £2000 mark. I then priced up the suggested rads (Quinn roll top ) TRV's plus a few packs of copper pipe and fittings from a local plumbing supplies outlet and the lot came to just over £600 and have just started installing as much of the pipework and rads that I can before I need to drain the system down and rip out the old pipework. So far its going well, and although I've planned how I would do it a 100 times in my head, in reallity its totally different as various issues are encountered and solved as the work progressed.

I have a few questions.

1) When I come to fill the new system for the first time how should I vent the rads. Should I simply open the vent on each one in turn or is there a procedure such as doing the downstairs ones first.

2) I did a search on the forum and from what I can see it matters not which side of the rad the feed and return is fitted, which can save crossed pipe work - such as having two rads fed from a tee where the two inner valves would be connected off the same pipe. - is the correct for normal locksheild valves.

3) I propose to fit TVR's on the bedroom rads (upstairs) and the hall (downstairs) - should these be fitted to the feed or the return pipes

4) I'm confused over the issue of adding the chemicals (fernox ?) to the system. Should I simply fill the system with water when complete and test for leaks, then drain down when satisfied that there are none and then re-fill (presumably adding the chemicals first to the feed / expansion tank then topping up with water)

I must admit that I'm chuffed to bits with the results so far (one lounge and the kitchen rads fitted with the pipe work all neat and paralle with a run up to the bedroom floor above) - and its only taken me 7 hours and just one small cut on a finger

Malc