baxi 80e hot water cuts out

[midgetninja]

Hi Guys,

First posting on here so please be gentle (unlike another plumbers forum)

I have got a Baxi 80e, in the last few days the hot water has been cutting in and out, the red led's got to 80 then the flame cuts out and then back in, not nice having a hot/cold shower!!.

There are no warning lights showing, pressure is ok at 1.5bar. 5 months ago we had the following replaced under BG plan. Diverter valve, heat exchanger, several sensors, filling loop and a few other bits!!!

Any suggestions?

Ta

 

[Puddle]

Well if you had all that done 5 months ago the boiler must have been in a very bad way and for that to happen, so must your system
Problem would point to faulty hot water thermistor or blocked up plate heat exchanger
But think if you have blocked boiler again after over 5 months system will also required cleaning out

 

[midgetninja]

Well if you had all that done 5 months ago the boiler must have been in a very bad way and for that to happen, so must your system
Problem would point to faulty hot water thermistor or blocked up plate heat exchanger
But think if you have blocked boiler again after over 5 months system will also required cleaning out

Hi, thanks for reply, the parts were changed by Bg as i called them out for the diverter valve due to rads getting hot when h/w run, the engineer was looking over the boiler and decided it would be better to all the other bits as well, he told me the dhw exhnager was not covered under the plan but in his words "sod it, its not my money"! the filling loop was leaking into system as well. When he left I almost had a brand new boiler!!

I am a bit loathe to call them out again as it cost me £120 per time, is the thermister the same as the diverter valve? if so then it will be covered under the 12 month warranty by BG

 

[Puddle]

No,but it may come under the 'several sensors'bit

 

[midgetninja]

Problem would point to faulty hot water thermistor

So would that be the DHW temp sensor? or the safety thermostat?

 

[Puddle]

DHW temp sensor/thermistor

 

[midgetninja]

DHW temp sensor/thermistor

Many thanks Puddle, appreciate your help

 

[chelsea]

when i have come across boilers that are intermitant with the hot water

going hot and cold and boiler doing the same on/off etc with the gas it can secondry heat exchanger getting blocked and the thermister senses overheat thats why it shuts down then when cooled it fires up again

clean exhanger or replace

 

[Puddle]

Thats not the thermistors turning burner on and off they modulate current to pcb to allow gas burner modulation
what turns burner on then off when over heating is the limit or over heat thermostate.this would most likely be caused by faulty thermistor or as you say blocked plate heat exchanger, if happening on hot water mode as mentioned above.The other possibility to take into account is the gas pressure is set to high on high flame and not modulating down to correct pressure on low flame if moduating at all