Proheat X45–School Bus - Manual (Page 40)

SECTION 3. INSTALLATION 3-19
Note also that the Supplemental Heat Mode has priority over the Preheat
Mode and will cause the Preheat Mode to drop out.
NOTE: There is a thirty second delay in response to both an “ON” and “OFF”
signal * . This is to allow time for the vehicle to start before the heater
is activated in Supplemental Heat Mode.
* There are special OEM versions for Supplemental Mode. For example, temperature thresholds may have a low
threshold of 160ºF (71ºC) rather than 150ºF (65ºC) and a reduced coolant pump Pre-run time of 30 seconds
rather than three minutes. Please contact Proheat Technical Support for more information.
Preheat Mode
For those fleets with outdoor parking, preheating is often essential in order to
start the engine in cold weather. Since much of an engine’s wear occurs during
start-up, preheating. Preheating reduces this wear and contributes to longer
engine life and reduced operating costs.
The Preheat Mode is activated by use of a momentary contact switch. This will
typically be activated each morning by the maintenance personnel an hour or
so prior to pull out. The Proheat then runs in a mode similar to Standard Heat
Mode, heating the coolant which is circulated through the engine block. The
advantage of this system is the manner in which it is switched off. No operator
input is required. The Proheat has a built in time-out feature to prevent the heater
from running indefinitely. If the bus is not needed for pull-out, the Proheat will
switch itself off after 90 minutes of operation. Starting the engine will also
cause the preheat mode to end (if Supplemental mode is wired). To manually
end preheat mode simply depress the momentary contact switch.
Please refer to the wiring diagrams on page 1-4 and page 3-21.
Select one of the following wiring options
NOTE: PROHEAT IS NOT RESPONSIBLE FOR CHANGES IN ELECTRICAL
SYSTEMS BY ORIGINAL EQUIPMENT MANUFACTURING COMPANIES.
Option A: Run the PROHEAT in Preheat Mode or Supplemental Mode alone.
Option B: Run the PROHEAT in the Preheat and Supplemental Mode.
Option C: Run the PROHEAT in Standard Mode (Proheat Timer optional)
and using the Supplemental Mode.
OPTION A – Preheat Mode or Supplemental Mode Operation
The instructions below are general in nature. It is up to the installer to select
appropriate switches and use proper electrical connection methods. If more
information is required, contact your Authorized Proheat Dealer or Proheat
Product Support at www.proheat.com
1. Select the operation mode of choice. Note that Preheat may be wired as
Preheat Option 1 or Preheat Option 2 as shown in Figure 3-29. In
addition, note to that the engine run signal may be off the alternator,
multiplex or others.
2. Wire the Preheat Mode or Supplemental Mode as shown in Figure 3-29.
Install hardware as required on the vehicle.
3. Install an Indicator Light near the vehicle operator.
You Choose
☞
3.5.11
WARNING
When wiring for Supplemental
Mode, ensure to install Mechanic’s
Disable Switch in order to
disable Supplement Mode for
safety requirements.