Baxi 100/2 HE Boiler Problems

[Jennieb]

Hi there,

I have a fairly new (just over a year old) Baxi 100/2 boiler. Just recently it has stopped working--always going to lockout. Pressing the re-set button will make it start again but only for a few minutes. The boiler thumps and bangs trying to start. Has anyone any ideas how to fix this? Any help & advice greatly appreciated. Thanks, Jennie

 

[corgiman]

the pump is eiher stuck or requires replacement, there should be a screw on the front of the pump which you can remove to get to the spindle ( it may be a nut i really cannot remember sorry) then you can pop a flat head screwdriver in and spin it to free it up.

be careful as some water will come out of the pump.

 

[Jennieb]

Thanks so much for the info. I'll have a go at that. Thanks, Jennie

 

[corgiman]

good luck

remember the screw is on the front of the pump, dont undo anything else or you may get wet

 

[Jennieb]

Thanks! J

 

[corgigazza]

Early models of these boilers suffered from pcb problems there is a new pcb (green dot) and additional mains filter(supressor) will need fitting.

 

[Jennieb]

Hi,

Thanks for your reply--can you tell me what a pcb is? Really showing my ignorance now! Jennie

 

[corgigazza]

pcb = Printed circuit board, shame the boiler over 1 year baxi would have done the work free of charge

 

[Baxi-Remeha]

TURN POWER OFF BEFORE REMOVING COVER 325V DC CURRENT

what lock out code are you getting, this can be found in your manual, by matching up the lighting sequence....

 

[cozzmic]

The other thing it could be is a faulty micro switch in the motorised valve which leaves the power onto the boiler and the pump but with the valve shut it can't pump against anything causing the boiler to boil,crash and bang. I have the mark one of these boilers (Barcelona) and this is a problem I've had with the Hot water Danfoss motorised valve.

 

[Jennieb]

Thank you so much to everyone who has helped with this. I have an engineer coming tomorrow afternoon--thought it would be safer to leave it to an expert--I'll pass on all the info here. This is not the weather to be without heating! Thanks again. Jennie

 

[noonespecial]

Sounds like poor water flow rate through the boiler. Could be the primary heating flow and return are too small diameter, pump faulty, pump not capable of duty, by-pass valve not correctly set or not provided, blockage in pipes.

 

[Jennieb]

Hello everyone,

Thought you might like to know that t he engineer has discovered there is some dirt in the system which has somehow got caught in the boiler causing it to go to lockout all the time. He now needs to clean it which involves taking it off the wall and cleaning it thoroughly. Does this sound plausible? Jennie

 

[noonespecial]

Is that dirt in the water ways or dirt in the electrical components?

Dirt in the water ways would need to be flushed through and would need the boiler to be taken down. Dirt could cause a partial blockage to water flow and the boiler could therefore be locking out on high temperature cut out. If that is the case why is there 'dirt' in the system, what is the 'dirt' and is there more lurking somewhere which could manifest as a problem again. It would be safer for you to also have the complete system chemically cleaned / flushed through and inhibitor added as well.

Dirt in electrical components / connections could also cause problems but are almost certainly accessible with the boiler in situ.

But has the design been checked?

There is no technical information on Baxi website on this boiler about the boiler pressure drop. Some of the larger condensing boilers now have rediculasly high pressure drops which makes normal domestic pumps totally unsuitable. Do you have the installation instructions ? If so can you check what the pressure drop is and at what temperature differential it will be something like metres head, kPa, Pa.

The absolute minimum pipe size coming away from the boiler will need to be 28mm if the system has been designed fro a 20 deg.C temperature differential or 35mm if it is designed fro an 11 degC differential. If the pipe size is 22mm it can be expected the boiler will not work.

 

[Jennieb]

Hello,
Thanks for your reply. We live in an old cottage (c1800) which had a pretty ancient (1971) oil fired central heating system when we bought the cottage. We built an extension and changed to gas. The new boiler is now in the house (the old one was in an outbuilding)--and it had to be connected up to the old system. The engineer thinks that there might have been some dirt in the old system--as we used some of the old radiators/pipework. He has suggested chemically flushing it through although didn't mention the inhibitor. He also didn't mention cost! Jennie