BAXI BAHAMA

[gasmanuk]

There is no contradiction baxipot the dhw works fine, lights first time everything. The flames and the neon light.

I don't know how well you know these boilers but I do know them quite well as I have repaired many over the years and I know the flame lit neon comes on as the burner comes on not after flame retifacation. Yet the light and the burner both come on and off in central heating mode

 

[ChrisR]

Ok what is there you haven't changed, which is different between CH and HW?,

-Signal from DV
-External switched live Signal
-CH sensor
-How does it check system pressure.. could sense different pressure on ch

Something might not tbe the fully open/closed circuit it should be.

Good one, isn't it

 

[gasmanuk]

external switched live has been bridged, signal from dv is constant, ch sensor is dry clickson stat so had one on van and tryed, I don't know how it checks system pressure I don't think it does prob relies on overheat????

Im thinking wiring loom etc but yes thanks chris it is a good one and its driving me mad.......but if it was the loom why does it light and stay on after 5 times????



aaaaarrrrgggghhhhh

 

[baxpoti]

I still think its a gas valve problem low gas not high enough!
DHW goes straight to high gas
CH stays on low gas for the frirst 60secs

 

[ChrisR]

Can you force high mod on the GV? What's the voltage?

 

[gasmanuk]

even though the fan drops out at the same time baxipot????

why would the gas valve drop the fan to low speed??

 

[baxpoti]

Trying to clear up a few points to get a better understanding of what's happening
Honeywell controls. The burner on light illuminates when the APS is proved, the ignition sequence then starts.

The Bahama does not check system pressure, air pressure switches can melt if system dry fired!

You said earlier on the 'gas valve controller' pin 8 and pin 10 control the demand e.g flow switches' ?

On the CVI unit (which you have replaced?)
Pin 8 (white wire) is to the APS
Pin 10 (red wire) is to the red lockout neon

There is no low fan speed, its on or off

The CVI unit controls the fan

I've not known of any problems with wiring looms on the Honeywell version

 

[gasmanuk]

there is low fan speed because 1) i've seen it and 2) baxi themselves said it would go to low fan speed??

I have no instructions the guy from baxi told me pin 8 and 10 control the demand

With all this in mind do you have any idea????

 

[baxpoti]

Whoever you spoke to at Baxi has given you incorrect information.
There is NO low fan speed on a Bahama, Honeywell or SIT version.

If you have a low fan speed on your Bahama you have a fault.
This fault would seem to be connected with the other symptoms

Test Fan (voltage on ''low speed'' pin 5 and 6 on CVI unit)?
(APS will drop out on low fan speed and give lockout)
Replace CVI unit if not 230v on 5 and 6 and on 1 and 2 with fan running.

If the CVI has been changed it could be the gas valve taking out the CVI?

Check gas valve for correct modulation (set high and low gas)
Check sensing electrode is in flame on low gas (sparking will stop)

 

[baxpoti]

Any joy Gasmanuk?