Proheat X45–School Bus - Manual (Page 94)

5-37 SECTION 5. TROUBLESHOOTING & REPAIR
Heater Operational Problems that are not specifically described in the
function or component diagnostic section.
COMPLAINT: Smoking exhaust/Smelly exhaust fumes
These symptoms are usually an indication of an extremely rich air/fuel mixture.
a) Is the PROHEAT connected to the correct voltage? (page 5-18)
b) Is the blower functioning? Is the air inlet restricted?
c) Is the compressor functioning? (page 5-23)
d) Is the exhaust restricted?
e) Is it a new heater? New heaters may smoke for 15 minutes as oil is
burned off the exhaust pipe.
This is normal.
COMPLAINT: Low heat output
If the heater appears to be functioning properly but the driver complains of
low heat this is often indicative of a coolant flow restriction. (See section on
Coolant Flow page 5-16).
COMPLAINT: Engine temperature gauge reads low
Depending on its location, the engine temperature sensor may not be directly
in the path of coolant flow from the heater. In these cases the gauge may
read significantly lower than actual coolant temperature.
COMPLAINT: Backfiring
Backfiring occurs when there is air in the fuel supply lines.
a) Fuel level in tank – is the pick-up submerged?
b) Air leaks – are all the fuel line clamps tight?
c) For severely restricted combustion air blockage at the blower inlet, in the
combustion chamber, or in the exhaust system.
OPERATIONAL PROBLEMS
Check
Check
5.3
5.3.1
5.3.2
5.3.3
5.3.4