problem with my Biasi M90 24S boiler
- Thread starter Skurze
- Start date
Sponsored Links
these boilers require volt free external controls, if there not, over time it will damage the pcb.
They actually send 230v out to your stat and look for it to return, so it is deceptive to think of them as volt free. What is important for these pcb's is that they are not fed from an alternative 230v signal other than the one which the pcb sends out.
Sponsored Links
Feel the heating return pipe (the one which goes to the pump) it will be red hot. You will have debris from your water supply holding a flow sensing shuttle stuck in the position which tells the boiler to fire. The boiler fires but since there is no actual water flow it gets flaming hot and the overheat protection kicks in, then after the pipe cools below overheat temp it fires again, add infinitum. Because it is in this state it will not work for heating, since combis always prioritise hot water, and your dumb pcb can only know what it has been told by it's sensors, which in this case it is misinformed.
I dont know if you received my last mail because i pressed the wrong key.
( I am, after all, a 70 year old computer illiterate. ) But at the moment all appears well & your advice was extremely well received .
Many thanks for your expert knowledge.
( I am, after all, a 70 year old computer illiterate. ) But at the moment all appears well & your advice was extremely well received .
Many thanks for your expert knowledge.
My idea was best guess for that boiler, it isn't exactly common but sometimes the sensor which detects demand for hot water sticks usually due to debris in the water supply.
If the boiler won't provide heating but will provide hot water and the flow pipe is red hot this has happened.
If that is the case you would best ask Biasi who in your area fixes them and get the part cleaned and the filter cleaned also, both parts are deep inside the boiler, and beyond the parts of a boiler you are meant to tackle especially at your age.
I am only 53 but with what I know I am very scared of how I will keep appliances going at home as I get older. I think i'll try to keep my hand in as long as possible.
If the boiler won't provide heating but will provide hot water and the flow pipe is red hot this has happened.
If that is the case you would best ask Biasi who in your area fixes them and get the part cleaned and the filter cleaned also, both parts are deep inside the boiler, and beyond the parts of a boiler you are meant to tackle especially at your age.
I am only 53 but with what I know I am very scared of how I will keep appliances going at home as I get older. I think i'll try to keep my hand in as long as possible.
I would like to add a few comments to what Paul has said.
If the boiler is stuck on a DHW demand then thats usually the older type of Hall effect sensor which has a red indicator LED when its activated and this can be seen after removing the front cover behind and to the left of the pump.
In that case its usually the return pipe which is hot and the boiler cycles keeping itself hot. If in good condition the diverter valve gives a good seal at the flow pipe but the hot boiler water expands down the return pipe ( against air at the tops of the rads ).
In this condition the boiler will not give any heating.
If heating is required then the boiler can be unstuck on a temporary basis by pulling forward the Hall effect sensor until the red LED goes out. For water push it back.
Tony
If the boiler is stuck on a DHW demand then thats usually the older type of Hall effect sensor which has a red indicator LED when its activated and this can be seen after removing the front cover behind and to the left of the pump.
In that case its usually the return pipe which is hot and the boiler cycles keeping itself hot. If in good condition the diverter valve gives a good seal at the flow pipe but the hot boiler water expands down the return pipe ( against air at the tops of the rads ).
In this condition the boiler will not give any heating.
If heating is required then the boiler can be unstuck on a temporary basis by pulling forward the Hall effect sensor until the red LED goes out. For water push it back.
Tony
check pump is turning (getting to heat circulated) if not it is reading too hot and cutting out.
I changed the thermistors on a biasi this week so I would check them if the pump is turning.
how soon is it cutting out when you select heating?.. maybe once its cooled down?
I changed the thermistors on a biasi this week so I would check them if the pump is turning.
how soon is it cutting out when you select heating?.. maybe once its cooled down?
C
compheat
I've just priced up a Pump for this model They want £135 just for the head and £190 for the compleat head/body
They want £135 just for the head and £190 for the compleat head/body 
whats the relavence of dancing when the op wants a fault code
C
compheat
No relevance at all. Just pointing out that spares are expensive.
Should i keep quiet and just read the posts
No relevance at all. Just pointing out that spares are expensive.
Should i keep quiet and just read the posts
why i don't
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
