Proheat M125 - Manual (Page 34)

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.
4. Ignition The Motor and Coolant Pump start first, followed by the ignition spark, and then
Fuel Solenoid Valve opens. The Ignition Module sparks for up to 30 seconds
during which time the flame sensor must detect a correct flame.
• If the PROHEAT detects proper flame at any time during the 30 second
ignition cycle, the PROHEAT enters Full Output.
• If the PROHEAT does not detect proper flame during the 30 second ignition
cycle, 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'S Dual Mode Temperature Sensor. The PROHEAT
closes the Fuel Solenoid Valve and goes into Cool Down (Purge).
The Motor and Coolant Pump continue to operate for three minutes. After
three minutes, the Motor and Coolant Pump stop and the PROHEAT enters
Supplemental Standby (coolant pump off). 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.
The Coolant Pump is “OFF” but the G-II PCM continuously monitors the coolant
temperature. If the coolant temperature drops below 160°F (71°C), the G-II
PCM will enter the cycle starting at Pre-run. The PROHEAT will continue to
repeat Steps 2 to 6 until it is switched “OFF.”
If the coolant pump is requested on via the coolant pump input (analog or CAN)
the PROHEAT enters Standby (coolant pump on). If the coolant temperature
drops below 160°F (71°C) the PROHEAT will move directly to Pre-check (step 3).
If the coolant pump is no longer requested on via the coolant pump input
(analog or CAN) the PROHEAT enters Supplemental Standby (coolant pump off).
After a 5 second delay the ON/OFF switch lamp, timer lamp or OEM indicator
(installation options) will turn off. In addition, the G-II PCM Indicator Light will
turn OFF.
If the PROHEAT is in Full Output, it will Cool Down (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 diagnostic code(s) which best represent the
conditions. The flash codes will be shown on the G-II PCM Indicator diagnostic
in RED. In addition, the ON/OFF switch lamp, timer lamp or OEM indicator
(installation options) will also flash the same code(s). To reset the PROHEAT,
it must be switched off and then on again.
NOTE: Damage may occur it the diagnostic codes are ignored and the PROHEAT
is repeatedly switched off and on without addressing the problem.
7. Supplemental
Standby
(Coolant pump off)
7A. Standby
(Coolant pump on)
8. Supplemental
Mode Signal
Removed
(Engine off)
9. Fault Shut
Down
5. Full Output
6. Cool Down
(Purge)
OFF
RED
2-9 PROHEAT M-SERIES G-II PCM SERVICE MANUAL