Service manual

— Page 80 —
© January 2013 Aqua-Hot
®
600-D01 Series Hydronic Heating System Service Manual - Rev. A
SECTION 9: DIESEL-BURNER COMPONENTS
Fuel Pump Replacement Procedure:
1.
Locate and disconnect the C-Plug harness wires that
connect to the flame sensor and the fuel solenoid.
Also, disconnect the ignition cables from the igni-
tion electrodes.
2.
Remove the retaining clip that secures the photo
disc in place. Gently lift the photo disc so that it
releases from the nozzle stand and the ignition elec-
trodes.
3.
Loosen the supply and return banjo bolts to remove
the fuel supply and return pipes from the fuel pump.
Also, disconnect the high pressure fuel pipe from
both the fuel pump and the nozzle stand. Discard
the high pressure fuel pipe, gasket rings, and banjo
bolts , as replacements are provided in the new fuel
pump kit.
4.
Remove the four nozzle stand plate screws that se-
cure the nozzle stand plate in place. Remove the
nozzle stand plate by pulling on the nozzle stand
until the plate releases from the cast-aluminum
blower casing.
5.
Remove the two pump mounting screws that secure
the fuel pump in place. Turn the nozzle stand plate
over and remove the snap ring from the fuel pump
shaft, using snap ring pliers. Remove the nylon
drive gear and then the fuel pump.
6.
Attach the new fuel pump to the nozzle stand plate
with the two pump mounting screws. Turn the noz-
zle stand plate over to install the nylon drive gear on
the fuel pump’s shaft and secure in place with the
snap ring. Dab the teeth of the nylon drive gear
with white lithium grease (Isoflex LDS-18 is recom-
mended.)
7.
Fit the nozzle stand plate inside the cast-aluminum
blower casing and secure in place with the four noz-
zle stand plate screws. Install the grommets on the
fuel return and supply banjo pipes and secure the
pipes to the fuel pump with the new banjo bolts and
gasket rings.
8.
Reconnect the C-plug harness’ violet (+) and brown
(-) wires to the fuel solenoid’s (+) and (-) electrical
terminals.
9.
Insert both the ignition cables into the rubber grom-
met and slide into the appropriate notch on the
blower casing.
10.
Reconnect the ignition cables to the ignition elec-
trodes.
11.
Reinstall the photo disc and secure it in place with
the retaining clip.
12.
Reconnect the flame sensor’s green wire to the
green C-plug harness and the blue wire to the
C-plug harness’ violet wire. Install rubber
grommet around the harness wires, and set into
place.
13.
Follow the directions for reattaching the diesel
burner in section 8 of this manual.
NOTE: To perform the following procedure it will be nec-
essary to remove the diesel burner. Follow the section on
detaching and reattaching the diesel burner, section 9 of this
manual.
NOTE
: Do not adjust the fuel pressure regulator of the
new fuel pump, as it has been factory preset.
Inspect the nylon drive gear’s cavity inside the cast alumi-
num blower casting for fuel stains. If fuel stains are present,
a replacement of the bearings and/or the entire blower cas-
ing may be necessary. Leaking fuel could cause bearing
seizure, resulting in potential damage to the internal bore/
bearing of the blower casing.
NOTE:
Failure to use the new gasket rings or the correct
order placement could result in a fuel leak.
NOTE:
Check the ignition electrodes for proper
adjustment prior to reattaching the diesel burner.