Aqua-Hot 375-d Service Manual page 76

S
ECTION
Replacement Indicator:
Replace if the Fuel Pump Leaks, or fails to pump fuel.
Component Test:
1. Clamp off the Fuel Supply and Return lines at the ports on
top of the Aqua-Hot; then, remove these lines completely.
2. Attach short pieces of fuel line to both the Aqua-Hot's
Fuel Return and Fuel Supply ports; reference Figure 31.
3. Submerse the hose connected to the Fuel Supply port into
a container of diesel fuel; reference Figure 31.
4. Place the hose connected to the Fuel Return port into an
empty container.
5. Turn the Interior Switch Panel's Diesel-Burner switch ON
to activate the Diesel-Burner.
NOTE: If fuel does not flow into the empty container from the
Aqua-Hot's Fuel Return port, and there are no air
leaks in the fuel system, the Fuel Pump Assembly
must be replaced.
Fuel Pressure Check and Adjustment Procedure:
For information regarding a Fuel Pressure Test and/or Adjust-
ment Procedure for the Diesel-Burner, please contact the Tech-
nical Support Department at 1-800-685-4298.
Replacement Procedure:
Be sure to clamp off the Fuel Supply and Return lines prior to
beginning this replacement procedure.
1. Following the procedure for "Detaching and Reattaching
the Diesel-Burner," located in Section 7 of this manual,
detach the Diesel-Burner from the Aqua-Hot.
2. Unplug the Cord-Set from the Fuel Pump Assembly's
Fuel Solenoid Valve.
8: D B
IESEL URNER
®
© 2009 Aqua-Hot 375D Hydronic Heating System Service Manual—Rev. A
C
OMPONENTS AND
3. Remove the Fuel-Supply Tube Assembly:
A. Loosen both hexagonal locknuts on either end of the
Fuel-Supply Tube Assembly with a 7/16 inch open-
end wrench.
B. Pull the Fuel-Supply Tube Assembly away from the
Diesel-Burner.
4. Using a 3/8 inch socket wrench, remove the two bolts se-
curing the Fuel Pump Assembly to the Blower Housing.
5. Pull the Fuel Pump Assembly straight out from the Blower
Housing.
NOTE: The Coupling may remain attached to the Fuel Pump
Assembly upon removal from the Diesel-Burner.
6. Insert the replacement Fuel Pump Assembly and attached
Coupling, if applicable, into the Blower Housing.
NOTE: In order to connect the Fuel Pump Assembly to the
Blower Motor with the Coupling, it may be necessary
to pull the Ignition Module Assembly back on its
hinge and rotate the Blower Wheel slowly until both
the Blower Motor and the Fuel Pump Assembly are
seated correctly on the Coupling.
NOTE: The Mounting Gasket must be replaced each time the
Diesel-Burner is detached from the Aqua-Hot; refer-
ence the procedure for "Detaching and Reattaching
the Diesel-Burner," located in Section 4 of this manu-
al for instructions.
R I
EPAIR NFORMATION
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