One for the Baxi boys.

[scatmanjohn]

Boiler= baxi comi 80 eco

Problem= intermittent overheating after a hot water demand (customer says usually after a bath).

Boiler works fine while i'm there

High/low bp set correctly. Boiler modulates in hw & ch.

Thermistor in range (stuck a new one on just in case its intermittent)

Return filter clean.

Baxi tech help suggest a diverter problem.

Any help appreciated

 

[Baxi-Remeha]

boiler may be overheating after the demand for a large amount of water. has it had the overheat kit fitted. this will make it so the boiler cant lock out on an overheat whilst the burner is off.

off the top of my head, part no. is 5115349. but check this as i may be wrong.

 

[scatmanjohn]

boiler may be overheating after the demand for a large amount of water. has it had the overheat kit fitted. this will make it so the boiler cant lock out on an overheat whilst the burner is off.

off the top of my head, part no. is 5115349. but check this as i may be wrong.

Not heard of that before...cheers.

Does the kit have a different type of overheat stat as this one is a mechanical type that requires a manual reset so does'nt "lock out" if you know what i mean.

 

[Rob]

was it the return thermistor you changed?

 

[Baxi-Remeha]

the kit includes a new overheat stat (self resetting) and a small wiring harnes. the kit converts it so the overheat interupts the flame recognition. if it over heats it will cause a flame failiure lock out needing a physical reset on the front controls.


as for the cause of the over heat, the plate may be scaled/blocked. causing the boiler not to be able to disipate the heat sending it over. but the oh kit is a cheaper alternitive and will cure the problem 99 times out of 100.

 

[scatmanjohn]

Thanks for that jason.

By the way you was correct with the part number......Geek

 

[Baxi-Remeha]

lol... i did look it up im my diary, but the pages are smudged. so had to guess the last no.

 

[scatmanjohn]

lol... i did look it up im my diary, but the pages are smudged. so had to guess the last no.

whatever

 

[scatmanjohn]

was it the return thermistor you changed?

There's only one on this boiler & thats on the flow close to the o/h stat

 

[gazthepottertonengineer]

John

in my experience it has been long dead legs of hot water pipework that have caused the nuisance tripping to occur after long draw offs

 

[scatmanjohn]

Just to follow up on this fault.

The new overheat update kit sorted the problem.

Thanks again jason

 

[Baxi-Remeha]

no probs bud, glad to help...