Functional Test; No Heat; Vacuum Generator - Monaco DIPLOMAT 2004 Owner's Manual

Functional Test:

• Start and operate the engine until the water reaches normal
operating temperature.
• Set the HVAC temperature control to the full hot position.
• The discharge air outlets should have hot air.
• Rotate the temperature control to full cold position.
• Allow 10 minutes for the temperature to stabilize.
• The discharge air outlets should have cold air.

No Heat:

• Check the blower and air mode operations. Repair prior to
proceeding.
• Verify the engine is reaching normal operating temperature.
(Check with engine manufacturer for proper procedure.)
• Check the inlet hose at the water valve. The hose has hot water
at the valve inlet. The inlet water temperature should be the
same as the engine water temp.
• With the temp control on full hot position, check the outlet hose
of the water valve. The hose should be at engine water
temperature.

Vacuum Generator:

The vacuum generator is important to the operation of the dash heating
and A/C systems. This provides the vacuum to open and close the vacuum
switches. When the vacuum generator is operating it creates 15 inches of
vacuum and is passed to a reservoir ball. Most dash heater and A/C systems
will only require 10 inches of vacuum to operate the switches. The output
from the reservoir is sent to the vent control knob. The control knob will then
direct the vacuum operation to the appropriate vacuum switch to open or
close vents and switches. The vacuum generator uses the air from the front
air storage tank through a 1/4 inch red air line. Whenever the ignition is ON,
and the A/C is operating, the vacuum generator will operate.
ELECTRICAL SYSTEMS - CHASSIS
DIPLOMAT 2004
030947
9 • 349