Hot water problem with BIASI combi boiler

[Vikki55555]

Hi,

I have 3 hot taps supplied by the combi boiler. All were working fine and then one day the kitchen tap stopped causing the flame to come on in the boiler and heat water. However, the bathroom tap continues to workeffectively.

Currently to get the boiler to heat water in the kitchen tap I have to run both taps until the boiler kicks in and then switch off the bathroom tap. The boiler then continues to work heating the kitchen water fine.

The boiler is a Biasi 24S. Not sure how old it is as it was already fitted when we bought the flat - we can say that it is defintely 5 years old or possibly more. It was last serviced in October 08.

If anybody has any ideas what might be causing this I'd appreciate your help.

Many thanks.

 

[gas4you]

Could just be the diaphragm needs replacing.

 

[oilman]

The flow switch is not operating. Could be too low flow rate caused by scaled pipes, could be failed flow switch.

 

[Vikki55555]

Thanks. How can I tell which it might be or should I just change all three things? Are they expensive.

Thanks again for your help.

 

[gas4you]

Turn on the hot tap and look if the pin comes out of the DV to actuate the microswitch.

If it doesn't then the diaphragm has had it. If it does it will probably be the microswitch.

To test further, remove the microswitch and gently insert a small screwdriver in it to operate the switch.

 

[Agile]

The DHW microswitch is behind the gas valve and almost impossible to see without an inspection mirror. Cannot be worked on without removing the gas valve so becomes a CORGI job if its leaking or failed.

I am just going out to do one of those in a minute.

We start off with the diverter valve and just do whatever is necessary according to what we find on site.

The boiler date is the last four digits of the serial number. 1996-2002.

Tony

 

[Vikki55555]

Thanks for these responses... so a CORGI person is recommended then? Any idea of approximate costs for this fix?

Thanks again - all very helpful and appreciated.

 

[Agile]

Most will be a diverter valve failure which can be done by a competent DIYer.

Some have a complication related to the DHW flow switch where a CORGI is needed.

I had a call later this evening about one with a faulted DHW flow switch. Property manager called her electrician first!

Tony

 

[Vikki55555]

Thanks Tony. Will let you know how it goes.

Life is one long learning journey (even for property managers )

All the best.