google espar DW4 for th manual.. W=Water, it is marinized for boats, the same as the 12v D4 in RVs. RV boards may have more diagnostic info. rule of thumb is turn them on every couple weeks -- even in summer or they won't start when you want them to.there is a drag wiring harness, a dealer can plug into it and diagnose it fast..
Recommended Periodic Maintenance
- Remove the glow pin and inspect for carbon build up. Clean or replace.
- Remove the glow pin screen and inspect for carbon build up. Clean or replace.
- Make sure vent hole is open. Espar recommends the use of non detergent 100% volatile carburetor cleaner, an air gun will also help. Remove loose carbon from the glow pin chamber.
- Inspect the ducting, the air intake screen and air outlet for restriction or blockage.
- Inspect combustion air intake and exhaust for blockage.
- Operate your heater for a minimum of 20 minutes each
month
- Maintain your batteries and all electrical connections in good condition. With insufficient power the heater will not start. Low and high voltage cutouts will shut the heater down automatically.
- Use fuel suitable for the climate (see engine manufac- turers recommendations). Blending used engine oil with diesel fuel is not permitted.
Basic Troubleshooting Check LIst:
What happens when the heater is switched on and ....
Heater does not ignite
1 Blower motor does not run
this section on troubleshooting
continues on for a while....
Check:
- Fuse in power harness.
- Power to control unit.
- Power to and from switch. - Electrical connections.
2 Blower motor runs approximately 20 seconds and then shuts off
Check:
- Ensure voltage at control unit remains above 10 volts during start up with glow plug circuit on.
3 Blower motor runs/fuel metering pump starts and then shuts down after two start up attempts
Check: - Fuel lines and fuel filter. - Fuel quantity. Pg. 23
- Combustion air or exhaust tube blockage.
4 Blower motor runs/ no fuel metering pump Check: - For electrical pulses at fuel metering
pump.
- If pump is frozen. - Blocked fuel line.
Heater ignites
1 Shuts down at random
Check: - Fuel metering pump quantity. Pg. 23
- Possible overheat.
- Control unit input voltage.
2 Heater smokes and carbons up
Check:
- Exhaust pipe blocked.
- Combustion air intake blocked.
- Exhaust entering combustion air intake pipe.
- Short cycling, rapid on/off operation. - Fuel system.
- Fuel metering pump quantity.
- Motor rpm.
