Problem with Baxi boiler

[mr_vampy]

Hi,
Hoping some of the central heating engineers can help me out with this. I had a Baxi Combi 105e boiler installed back in November 2002. Just recently there's been a neon ligh flashing at the 60c mark, and there's no hot water. According to the user guide it says it's either a fault on the pump or low pressure. The pressure has always remained on 1.5. I have always had to turn the boiler off, and then on again to get hot water working again. This has to be done on numerous occassions throughout the day.
Another fault that has developed is that when i have a bath/shower, the water keeps fluctuating from hot to cold.
Could this have something to do with the neon light flashing.
I'll be booking the boiler in for it's annual service in a few weeks time, but just wanted to have an idea what could be wrong with it.
Any info and advice would be greatly appreciated. Thanks in advance.

mr_vampy

 

[nogoodatfaultfinding]

Run your HW if all the neons come on then go off then light flashes i would go for the HW Thermistor but if not the PCB Mate

 

[mr_vampy]

Thanks for the advice. I've booked the boiler in for it's annual service on the 9th Feb, so I'll ask the engineer if it could be the thermistor or pcb that could be causing the problem.
Do you have any idea of an estimate cost for changing either component?
Thanks again

 

[Corgigrouch]

Never assume that the gauge is telling the truth... Boiler is not detecting water flow, so not enough water or pump is toast....Check everything before resorting to the PCB

 

[gas112]

First fault
You need to check pin on TOP of divertor valve is coming up and hitting the microswitch . It could be a faulty diaphragm or microswitch if both of these check out it will be a faulty board which is the more likely if it always fires for HW.

Second fault
HW Running hot and cold if the lights get all the way up to 80 then it cuts out and drop back to 50/60 and fires again it is likely to be a blocked plate heat exchanger

 

[Agile]

Thanks for the advice. I've booked the boiler in for it's annual service on the 9th Feb, so I'll ask the engineer if it could be the thermistor or pcb that could be causing the problem.

Do you have any idea of an estimate cost for changing either component?

Thanks again

You should not ask for a service on a boiler with a fault.

Firstly a boiler repair is more expensive.

Secondly the engineer may be a servicing only fellow.

Thirdly he is unlikely to have the parts with him if he is not advised of the boiler model and the symptoms.

Our charge is £55 to service a boiler but thats only if its working properly and we wait 7-10 days to avoid those who call us for a service when it needs repairing.

We charge a fixed price diagnostic fee of £84 in the local area and £18 for the sensor. PCB about £100 !

Tony

 

[mr_vampy]

Hi,
Just an update on my Baxi 105e boiler. The problems has now been fixed. It needed a new DHW heat exchanger, as the old one was blocked and water was flowing through it slowly.
The flashing neon light at the 60c turned out to be the pin was not coming up fully to hit the microswitch. Some grease has now sorted that out. )
Thanks again for the help and advice

 

[Agile]

The pin not moving enough to operate the microswitch will have been as a result of the restricted flow through the plate HE.

That could have been cleaned out rather than changed.

If you still have the old one then you could clean it ready for when the new one has blocked. Search for info on cleaning them.

I am surprised you had not noticed the deterioration in the hot water supply. I would have expected it to cycle hot/cold some while ago.

Tony