Desperate for help - Intermittent Hot Water from Baxi Bahama

7 Jan 2003
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United Kingdom
If anybody could help with this i'd be most grateful as we've got a new baby coming home in the next few days and I'd like to have some hot water available !!!

Following on from the problem I posted earlier this week I've done some more work on finding out why our Baxi Bahama 100 gives intermittent hot, lukewarm and cold water from the hot water taps and shower but I'm at a standstill again.

Someone suggested to me a new diverter head, so I tried this by using the diverter head from my brothers Bahama with no joy.

I've noticed now that when the hot tap is turned on, the boiler fires up and stays on for a few seconds (maybe 6 at most) during which time the tap water is hot. The boiler then goes off and the water goes lukewarm. If I turn the hot tap off then back on again, it fires up again and the same thing happens. If the radiators are on at the same time the result is still the same but the boiler sounds as though its stays fired for as long as the tap is turned on.

I saw on the forum a lockout problem for a Baxi but this was for a barcelona not a bahama and the symptoms were not quite the same as my bahama doesnt give me a warning light to say its overheating.

This morning I left the cold water tap running while I used the shower and i dont know if this was just a huge co-incidence but i could have sworn that it made the shower hotter for longer.

As I said before, the radiators throughout the house are piping hot and dont seem to be a problem. The water pressure is within the limits too according to the boiler indicator.

Any ideas anyone ??!!

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Does your boiler have a mixing valve that you can adjust to vary the hot water temperature?
2 common faults on this boiler
could be dhw flow switch - cheap and easy to replace
or dhw plate to plate heat ex - need to remove & wash out
oilman, not sure about the mixing valve - where would i find this ?

galwag, presumably common faults which cause the same symptoms i'm getting ? This sounds promising - any ideas where would be best to get the part from online ?
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You may not have a mixing valve, but it would be in the boiler cabinet, probably have a grey knob, and be numbered 1 to 5. If the water flow to the tap is OK, it is unlikely to be the heat exchanger.

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