Proheat M80 - Manual (Page 26)

PROHEAT G-I PCM SERVICE MANUAL 2-5
CAUTION
Always ensure that the PROHEAT is allowed to Cool Down (Purge) for a full 3
minutes. If the power is shut off without a proper Cool Down (Purge) during
Full Output, DAMAGE TO THE HEATER MAY OCCUR.
6. Standby
7. Switch “OFF”
8. Fault Shut
Down
The ON/OFF switch lamp, timer lamp or OEM indicator (installation options)
will light. If the coolant temperature is below 160°F (71°C) the PROHEAT
enters Pre-check. If the coolant temperature is above 160°F (71°C) the
PROHEAT enters Standby.
The G-I PCM performs self diagnosis checking sensors for correct range,
electrical components for over-load and for a flame presence. Also during the
first Pre-check, the Ignition Module sparks for five seconds to allow a service
technician to visually check for a spark. If there are no errors indicated, the
PROHEAT goes to Ignition.
The Motor and Coolant Pump start first, followed by the ignition spark, and
then Fuel Shut-off Valve opens. The Ignition Module sparks for 30 seconds
during which time the flame sensor must detect a correct flame. At the end
of the Ignition cycle the Flame Sensor checks the flame:
• If the PROHEAT detects proper flame, it enters Full Output.
• If the PROHEAT does not detect proper flame, the PROHEAT enters Cool Down
(Purge). The PROHEAT will attempt to start again moving into Pre-check
after Cool Down (Purge). If the second start cycle fails, the PROHEAT will
enter Fault Shut Down.
The PROHEAT will continue in Full Output until the coolant temperature reaches
185°F (85°C) at the PROHEAT outlet Temperature Sensor. The PROHEAT closes
the Fuel Shut-off Valve and goes into Cool Down (Purge).
The Motor and Coolant Pump continue to operate for three minutes. After three
minutes, the Motor stops and the PROHEAT enters Standby. The PROHEAT
will Cool Down (Purge) for three reasons:
• Coolant reaches 185°F (85°C).
• A fault is detected. Go to Section 4.0 Troubleshooting and Repair, page 4-1.
• The PROHEAT is operating in Ignition or Full Output when it is switched off.
1. Momentary Switch
“ON” Preheat
Mode Signal
2. Precheck
3. Ignition
PREHEAT MODE (ENGINE OFF) 2.2.2
The Coolant Pump continues to circulate coolant throughout the system.
When the coolant temperature drops below 160°F (71°C), the G-I PCM will
enter the cycle starting at Pre-check. The PROHEAT will continue to repeat
Steps 2 to 6 until it is switched “OFF.”
The ON/OFF switch lamp, timer lamp or OEM indicator (installation options)
will turn off.
If the PROHEAT is in Full Output, it will Purge first and then shut “OFF”.
If the PROHEAT is in Standby, it will shut “OFF” immediately.
If the PROHEAT diagnostics sense a system or component fault, the
PROHEAT will shut down all components and flash a fault code(s) which best
represents the conditions. To reset the PROHEAT, it must be switched off
and then on again.
NOTE: Damage may occur it the fault codes are ignored and the PROHEAT is
repeatedly switched off and on without addressing the problem.
4. Full Output
5. Cool Down (Purge)