Originally Posted by BigRuss (Post 877597)

When the heater has been running it will still operate after the ignition is turned off this is normal as it goes through a shutdown proceedure where ignition is cut, the internal fan then continues to cool down the burner, when cool enough the FBH will shutdown completely. ;)

Please don't go cutting the K-bus wire with no good reason, if weird stuff is happening to other electric systems then unplug the FBH, your PCB is faulty.

There for a very good reason for the K-bus, it's there for diagnostic purposes, the cars ZCS coding includes the heater, when on T4 and running a diagnostic it will look for the heater via the K-bus if this is cut then it doesn't find it and you won't be able to run a full vehicle diagnostic.
Makes the time diagnosing faults an awful lot longer because then each ECU then needs to be accessed seperately. (the same goes for anything connected to the K-bus, CAN-bus or Nav-bus.)

Russ

Originally Posted by Jakg (Post 877605)

D'oh, bit late now... can always reconnect it if needs be. Don't see any T4 sessions in the future though...

PCB isn't faulty (Mikes already checked it).

The problem is that even after driving for hours, with the car running at 80+ (using the inline stat), the FBH will continue running when I park up (no idea if its been running the entire time).

I understand it can run on to cool down... but it shouldn't of been on at all if it'd been hot enough for so long

Originally Posted by suffolk boy (Post 877678)

will do not any harm to solder it back up tho if i pull the fuse will it .or just use bullet connectors?

Originally Posted by BigRuss (Post 877618)

The FBH if the outside temp. is low enough doesn't shut down even when the coolant is fully warm it goes into idle mode ;)

72C = part load operation, anything above 76.5 the control idle mode cuts in, if the temperature drops then drops below 71C it will resume part load operation if the coolant temperature drops further as a result of heavy demand from the vehicle heater the FBH will resume full operation at 56C.

Shutdown proceedure after engine switched off:

175 seconds full load operation, 100 seconds part load.

Hope this helps.

Russ

Originally Posted by HarryM1BYT (Post 877225)

[note to mods - can this be made an HOW TO please, after a suitable time for any amendments and additions?]

Everyone else - please feel free to report any errors or amendments it might need......

Originally Posted by Jakg (Post 877716)

After my journey tonight...

When I started the car, it was at 33° C (still warm from my last journey).

It took 6 minutes of driving to get from 33° C to 75° C - I pulled over for a little while and noticed that the FBH seemed a lot louder than usual.

After a ~19 mile journey, the max temp attained was 84° C - it seemed to get to ~79° C quickly, then rise very slowly.

Could this mean my FBH is working properly now? Will give it another test tomorow...

Originally Posted by Jakg (Post 878028)

From 1° C -> 75° C took 10 mins this morning... sound like it's working or not?