Fault Guide : Smiths Combustion Heaters
There have been many different heater fault guides issued over the years.
There are two tables here, one being basic and one more in-depth. They both look mainly at the heaters themselves.
There are also a fault finding charts, which include the control systems, although theses are from a very dated drawing ("Diesel Office Ref: SK/CO/5/44") and deal with the clockwork/cam systems, although they are still of use. There is one for semi-automatic systems, and for through systems there is one for heat and vent.
Do you have any more versions? Please contact me.