fbh firing sequence
 

anyone no the exact chain of events to the fbh firing up.mine has packed up again.i thought it was the fuel pump as i could not hear it clicking.but its not that.so methinks the glowplug must also act as a temp sensor so when the fbh starts to burn fuel it turns the pump on to add more fuel to the fire so to speak.otherwise a failed start could cause slight issues to say the least.i am testing the lot on sunday but i like to no these things if its not i have a duff replacement pump

i will answer this myself after a quick read up .yes it does so despite the plug is new along with the burner that will be my number one suspect.will shall see on sunday

Here is the sequence, how far does yours get before it stops ?

Diesel
When starting the vehicle engine the heater goes in
standby. With a water circuit temperature below 60 °C and
an outside temperature below 5 °C (option with outside
temperature sensor) the starting sequence commences.
The glow plug and the combustion air fan are activated.
After 30 seconds the fuel dosing pump starts operation
and combustion air fan operation is suspended for
3 seconds. Subsequently the combustion air fan speed is
increased in two ramps within 56 seconds to nearly full
load operation. After a stabilisation phase (constant
speed) of 15 seconds the combustion air fan speed is
again increased in a ramp within 50 seconds to nearly full
load.
After reaching full load fuel delivery the glow plug is
deactivated and the combustion air fan operation
increased to full load.
During the subsequent 45 seconds as well as in normal
operation the glow plug functions as flame sensor to
monitor the flame condition.
After all these events the automatically controlled heating
operation starts. In case of a no flame condition or a
flameout, a restart is automatically initiated. If the no flame
condition persists, fuel delivery is stopped and the heater
enters an error lockout with a run-down of the combustion
air fan.

This may also be useful ;)

Brian :D

Faults

Fault lock-out due to faults in the heater

Fuel is supplied for max. 180 seconds if the flame does not start to burn.

Fuel is supplied for max. 85 seconds if the flame goes out during
operation.

The fuel supply is shut off immediately if the system overheats
(temperature limiter is tripped), the temperature limiter is a type J thermocouple clamped to the heat exchanger body adjacent to the BTS141 FET in a TO220 package.

In all cases (except a fault in the combustion air fan), the heater
continues to run for 120 seconds after a fault lock-out. The run-on
time may vary, depending on the software version in the control
unit.

IMPORTANT

A warning is not displayed following a fault lock-out due to overheating, except if reading the digital live data using T4

all very usefull currently turn car on and start it and as its has been minus 1 or 2 all this week. fan comes on runs for a fair amount of time ie about a mile on the road .then turns off. heater stone cold.will be testing all the bits one by one sunday using mikes magic tester then go from there.

that was done by french mike years ago.
may well have developed another.will test out all the bits tomorrow.i have a few spares so maybe able to fix it.if not after spending far too much money on it its coming off i cannot keep mucking around with it.life is too short as it is

basic test done placed my tester on the fan feed wire to be confronted with a audible screech from the motor and the fan does not work .so thats it for it now unplugged it all .cheapest fix yet.unless anyone has a spare fan cheap?

the pump you can test by flashing 12v across it. I think not only do you want to hear it click but you need to make sure fuel comes out at the engine bay.
I did see as post somewhere where pump clicked but was not pumping

macafee2

Is this any good?

LINK

Brian :D