Baxi Bahama 100

[K9]

My wife and I inherited a baxi bahama 100 from the previous owners of our house and it is constantly cutting out. On occasion it works and then at other times it will cut out for no apparent reason. When running a shower there is generally no problem, however, the bath seems to always cause the boiler to cut out. As far as the central heating is concerned, the boiler can be fine for a few hours and will then cut out. I am not sure if there is a loose connection as a gentle thump can usually get the boiler going again.

Somebody from our utility company came to look at replacing the baxi with a condensing boiler and quoted £3,000. I am not particularly keen to pay this type of money in a credit crunch and am therefore eager to repair the existing boiler if at all possible. Has anybody got any idea what the problem may be? I would guess that the boiler is about 5 - 10 years old?!

Any advice would be gratefully received.

Thanks.

 

[sloppytom]

Thumping the boiler on the side starts the boiler up because of the reed switch which comprises of two thin metal wires, flatened at the ends and gold plated (to stop oxidation) placed in a glass tube. When a magnet is in close proximity, the ends in the glass tube attract completing an electrical circuit.
Over time, the ends get magnetised and tend to stick despite lack of external magnetic influence. Spikes on the contact area can also effect operation.
In the Bahama switch assembly, the magnet that rides up and down due to water flow, can be arrested by sediment deposit to effect sequential operation of boiler system. A 'slap' put the magnet in the right place.
So the DHW flow switch would be first to look at.

These boilers also have major problems with there ignition boards and Pcb boards. When ever i come across these boilers i end up ripping them out.
3000 is a good price, you would be looking at that price with british gas who can give you 12 month service contract in price.

 

[Gas2Air]

The op never said which side he "thumped". True these flow switches are poor. By design. The CH flow switch is the primary so first thing to check. thermistor readings ok? gas pressure modulating?.

Probably never been serviced, so i'd hold onto the £3000.