Baxi Bahama 100...

[ElliotNorthants]

I wonder if anyone can help!?

I have a problem with my Baxi Bahama 100 combi boiler. The problem was intermittent and now seems to be a permanent issue. When I turn on the hot water everything seems to work, the gas comes on (looks like a reasonable flame) and I start getting hot water. However after about 5-8 seconds the system stops and I am left with cold water. This happens with both the Central Heating and the Hot Water

I have read a number of previous posts pointing to the flow meter being a big issue on this unit (the comments on the Baxi Bahama don't seem great, and the flow switch is clearly not the best design).

Looking at the maintenance manual then with this issue the flow diagram points to the flame sense electrode, ignition cartridge of gas valve. Which relies on checking burner pressure (something for an expert). Although I have skimmed through the fault diagram and am going to check in order tonight.

My questions are therefore:

1) Does anyone have any experience and can make a suggestion?
2) Is there any way to check the flow meter is working with a multimeter? (open circuit = dead?)

Thanks in advance

Elliot

 

[Agile]

I am not going to give you advice on gas or ignition matters.

Its unlikely to be the flow switch failing after the boiler has ignited as thats a water circulation issue.

However, you could, if competent, unplug it and join the two connections together just after the boiler is given a call for heat and see if that makes any difference but I dont expect that it will!

Tony

 

[grahamderek]

Probably a flow switch problem. This boiler fires up THEN checks for water flow(brilliant design!). The switches are very prone to failure, even though they were redesigned. In DHW mode, both switches need to operate, in CH mode only the CH flow switch operates. Both switches are the same, although one has a spring inside, which must be retained. They are simple open/closed switches, and easy to check and change, but be very careful not to get water into the electrics.

 

[Vic Spanner]

Diffo flow switch replace both whilist your at it. Clean inside of primary flow switch housing as well when the old switch is out.

 

[superdupergasman]

Could also be a thermistor problem although the ones on these boilers are clipped to pipe and therefor not too bad.

OR!!!

It could be you have the good old honeywell ignition box on the gas valve
that are prone to failure also but then again you may have the SIT gas valve.

Lots to check!

 

[baxpoti]

Diffo flow switch replace both whilist your at it. Clean inside of primary flow switch housing as well when the old switch is out.

Excellent advise.

 

[Vic Spanner]

Could also be a thermistor problem although the ones on these boilers are clipped to pipe and therefor not too bad.

OR!!!

It could be you have the good old honeywell ignition box on the gas valve
that are prone to failure also but then again you may have the SIT gas valve.

Lots to check!

Stops after 8 secs.......Flow switch

 

[superdupergasman]

not worked on one for a while poxi...i'm a wee bit rusty!!

 

[mikej2005]

The Bahama in my previous house had what I thought was a dodgy flow switch - if you didn't turn a HW tap on fully enough, the boiler would fire up, the flow rate would decrease and the boiler would shut down and lock out.

Changing the DHW flow switch helped, in my case.

 

[ElliotNorthants]

For anyone else with the same problem as me, here is what happened!

Well, I bought some flow switches online and got them today.

Changed both (found alot of debris in central heating flow switch - switch was not right when I bench tested it!).

Surprise surpise the system works again!! Had a false start when I didn't change both switches at the same time (thinking one was the DHW and the other was the CH and both are separate).

Thankyou everyone that replied to my post. It is really nice to know that there are people out there willing to help out others!

Thanks again

Elliot