ariston euro combi 27mffi overheat lockout

[moony]

went to view a ariston combi 27mffi last week keeps going to over heat lockout it was for a friend and i only had 5 minutes to have a look - i opened up the nearest rad and it was fine for a few days - i said the pump may be on the way out but as i say i only had 5 mins to check it out.

he has now bought a pump on that prognosis.

anyone had any dealings with this - do the temperature stats go on these - it sound slike a definate circulation problem to me but im thinking the temp stat may be faulty too?

any thoughts - im going back weekend as its quite far from me - i may get a temp stat if theyre prone to failing on this - hes also going to give the system a slude remover treatment tmrw night and let it run for a few days and i'll drain and change pump on weekend - anything i should check and if any of you have had any dealings with this then let me know.

cheers


moony

 

[RoryD]

check fow / return temp, there should be about 11 degree diff, if greater then it is a circulatory prob. Bleed rads, top up pressure; run bouler and check temperatures. Usually the cause innit?

 

[Billy Bob Bob]

could be a stat,but pumps are prone to failing was it constantly trying to ignite? not recognised detection and going to lock out? pcbs are weak and this is a common fault sounds like its a microgenus 27 mffi

 

[Billy Bob Bob]

check fow / return temp, there should be about 11 degree diff, if greater then it is a circulatory prob. Bleed rads, top up pressure; run bouler and check temperatures. Usually the cause innit?

no i know this heap well

 

[moony]

haha.

GM its lighting fine then once lit getting up to temp - then running for a 5 mins and then overheat lockout - like i said i opened the rad next to boiler up and it ran ok for a few days (daughter had shut it off) - the pump was red hot. i checked the over heat stat and that was cutting out at right temp, but didnt have parameters on me to check the ntc temp stat - to be honest ive not worked on an ariston before, he had no bloody book and for the life of me i couldnt fathom how to get the control panel down at first - done it in the end but what a silly way of doing it having to push the sides out to get it out! ah well maybe im spoilt buy all the worcestors and baxis ive seemed to be going to lately.

more likely the pump then ? so should i leave the temp stat in the merchants

 

[Billy Bob Bob]

there was a mod on stat position but the new one(should)advise of this but it only played up in dhw mode,does sound like pump/lack of circulation issue but pumps are dear for this heap,and often leak on the gasket between plastic housings when changing the pump make sure you have silicone to hand and smear the gasket's well obviously without looking at the fault doing my best to advise good luck moony you will need it

 

[gasmarc]

it could be a circulation problem but I presume if the rads are getting hot this is not the case, the ntc on these can go iffy if there is a leak above it, good luck

 

[Billy Bob Bob]

it could be a circulation problem but I presume if the rads are getting hot this is not the case, the ntc on these can go iffy if there is a leak above it, good luck

quite right forgot about that one but does this affect the genus more than the microgenus?

 

[Billy Bob Bob]

bugger gasmarcs right i was looking at a different boiler my fault replying to multiple posts,you need to check this first moony a common problem,the ntc getting wet boiler does not turn off and gos to overheat sorry mate i thought this was a microgenus different combi

 

[gasmarc]

I am not sure gas man they are very similar they did a micro genus and a two also ,if memory serves me right the diverter valve leaks down onto the ntc , and an other thing to be very carefull of is the internal filling loop and those blue taps, one of the pigs popped out on mains pressure lol but I managed to get it back in .they also shear easy