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535i Andrew

Boiler advice.

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Baxi boiler in the house has decided to "lock out"  quite frequently.

 

System will call for heat, green light comes on and makes no effort to fire up and goes straight to red light on "lock out". 

 

It will do this when cold so to my train of thought this is not an overheating issue.

 

Pump is 7 years old.  Pump appears fine and I can hear it work but it is not in an accessible location helpfully! Zone valves 7 years old but both have had new electronic actuator heads fitted in the last 18 months.

 

Turn knob on boiler to off and back to desired setting and all is well and it will fire up and run perfectly for anything for a few hours to a week.

 

I have replaced all the radiators in the house and about 50% of the pipework over the last 10 years so the system has been drained and filled a lot recently last job was carried out before Christmas and has run perfectly since until two weeks ago.

 

It has done this before and usually a bleed of all the radiators helps.  I've bled all the rads this time but its still doing it intermittently.   

 

Its either air in the system right at the boiler that is refusing to shift or something amiss in the boiler itself with perhaps one of its internal valves.  Possibly sludge or debris as got stuck over a sensor or internal valve with all the draining and re-filling I have done recently?

 

I'm wondering if another drain and refill will help, before I phone out an Engineer and get hit for the £60 excess on my policy that I agreed to at the time of renewal to get a sensible renewal premium of my homecare agreement. 

 

Any thoughts other than call out an Engineer and stop being a tight @r$e?  

 

 

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Probably sticky diverter valve, check youtube for your boiler. I have a problem with a Gloworm (Vailant), when the heating cuts off and throws a F9 code when demanding heat again. The diverter valve was leaking which was replaced and differential switch also has been replaced. The culprit with mine is sticky diff. pressure switch.

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Assume it has no handy panel on the front or flashing light to blink a fault code.  If it doesn't fire up at all from cold, I'd suggest it isn't locking out due to overheating - it would have to at least run a bit for that. So if it has a pilot light, is it lit, steady, and is the thermocouple positioned correctly? And has the thermocouple been changed in the last 7 years?

Edited by whiskychaser

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Some boilers have some kind of automatic air bleed valve on them. THey can stick. I had this when I changed a rad for a friend. Topped the system up and it wouldnt fire up. I phoned my Corgi guy and he talked me through it. The solutioninvolved a gentle tap with a hammer. Probably worth checking your manual to see if you have one

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19 minutes ago, healeyneil said:

Some boilers have some kind of automatic air bleed valve on them. THey can stick. I had this when I changed a rad for a friend. Topped the system up and it wouldnt fire up. I phoned my Corgi guy and he talked me through it. The solutioninvolved a gentle tap with a hammer. Probably worth checking your manual to see if you have one

 

Automatic bleed valve is located on the pump, left unscrewed during commissioning of the boiler.

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Thanks lads.

 

Yes, front panel is removed to access dial and to see red led lock out, but it doesn't blink out a code.

 

Thermocouple was replaced no more than two years ago. It self ignites so no pilot light and you can't see any flames when it's running as it's all sealed.

 

Its worked fine all day since I reset it at 6am.

 

I have a manual for it, I'll need to hunt it out.

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10 hours ago, jake13 said:

Tell us model number of Baxi boiler and picture with front panel off.

 

Lol, I knew that was coming. There isn't a model number anywhere on the casing. I'll take a picture tonight.

 

It's worked since yesterday am so I didn't spend much time looking over it last night.

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22 hours ago, jake13 said:

Tell us model number of Baxi boiler and picture with front panel off.

 

Here you go Jake

 

image.jpg

 

It's  a Baxi 100 HE. Open vented system with header tank in the loft. Picture above shows it on green led and yellow led means is burning gas. The red led to the right is off nad that's the lockout warning.

 

Googling the model and intermittent lock out suggests that the condensate trap is a possibility, but mine was cleaned out in the last 18 months after it over flowed.

 

It had tripped out again when I got in tonight and I bled all the radiators again and got a little bit of air out, so I'm fairly confident it's not caused by it being too hot or there being air in the system.

 

 

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So had another look last night, condensate trap has a sump plug on the underside, can't be that hard for gone past 10pm.

 

Unscrewed it

 

image.jpg

 

and this is what came out after I tipped out the water.

 

image.jpg

 

Hmmmmm.

 

I remembered that we had a leak from this back in Dec 16 and a fitter came out and cleaned out the trap, so that lot gathered in a little over a year. 

 

Happy thinking that I fixed it, I went to bed, to be woken at 6 am this morning by the littl'un complaining they were cold, it had tripped out again.

 

There is two parts to the trap I think so I suspect there is still something lurking in there. Need to take the cover off to check further.

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So an Engineer came out yesterday and was very grateful for the description of the fault.

 

He checked a few things out and then replaced the burner and the combustion chamber door/cover seal.  It runs very quietly now although since it last locked out on Saturday morning, it had been fine.  The law of sods!

 

He said the burner was in a very poor condition which explains why it would not ignite sometimes and then thru up the fault.

 

I'm guessing that this lot

 

image.jpg

 

is the metallic particles that used to be part of the burner!

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I attended a Baxi a few years back that kept locking out. Turned out the condensate was total clogged, the owner had been fitting a new patio with brick pavers, all the dust kicked up by cutting the bricks went into the boiler, it was actually weeping through the inspection panel seal. 

 

Most folk don't bother having their boilers serviced and to be honest 'If it's not broke, don't touch it', but these new boilers do need their condensate drains checked annually if they block you end up filling the combustion chamber very quickly causing damage

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Mine was serviced every year and condensate trap cleaned out by engineers every couple of years.

 

Its at an age where it needs replaced. 

 

How many 15 year old cars do you still see going? Not that many sadly, you could still buy a new E39 15 years ago.

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