Service manual

— Page 53 —
© January 2013 Aqua-Hot
®
600-D01 Series Hydronic Heating System Service Manual - Rev. A
SECTION 7: DIESEL-BURNER
Operational Flow-Chart
Operation sequence once the Aq-
ua-Hot’s Diesel switch is turned
ON
NOTE:
The Diesel switch’s indicator
light will illuminate anytime the
Diesel Burner switch is in the ON
position
The Motor (#2), which turns the
Combustion Air Blower (#5)
and drives the Fuel Pump (#14),
will begin to operate.
NOTE:
If the Aqua-Hot’s coolant temper-
ature is approximately 190°F (+/-
5°F) or higher, the Motor (#2)
will not operate. Only when the
coolant temperature has dropped
below 160(+/-5)°F, and the VDC/
VAC Control Thermostat is call-
ing for heat, will the Motor (#2)
begin to operate.
After approximately 10-25 sec-
onds, the Fuel Solenoid Valve
(#6) opens and fuel is sprayed
into the Combustion Chamber
(#11) through the Fuel Nozzle
(#9)
Simultaneously, the Ignition Coil
(3) produces a high voltage spark,
which is transferred across the
Ignition Electrodes (8). The in-
coming air-fuel mixture is then
ignited, creating combustion.
Once the ignited air-fuel mixture
(FLAME) is observed by the
Flame Sensor (#13) the Ignition
Coil (#3) will automatically
switch OFF. The combustion
process now continues to operate
unassisted.
The combustion process will con-
tinue to operate in this manner
until one of the following occurs:
A.) The VDC/VAC Control
Thermostat, which senses cool-
ant temperature, reaches the pre-
set temperature of approximately
190 (+/-5)° F.
NOTE:
If process “A” occurs, the Aqua-
Hot Heating Status Light on the
Electronic Controller will go
OFF.
B.) the Aqua-Hot’s Diesel Burn-
er Switch is turned OFF.
NOTE:
If process “B” occurs, the Diesel
Burner switch’s Indicator
Light, on the Switch Panel will
go OFF along with the Heating
Status and Diesel Burner Status
lights on the Electronic Control-
ler.
Once the heater switches OFF,
thermostatically or manually, the
Fuel Solenoid Valve (#6) closes,
which interrupts the supply of die-
sel fuel to the Fuel Nozzle (#9)
The Motor (#2) will continue to run
for approximately three (3) addi-
tional minutes. This process is re-
ferred to as the Purge-Cycle, which
cools the heater’s internal compo-
nents and purges the Combustion
Chamber (#11) of any residual
exhaust gases.
NOTE:
When the Aqua-Hot’s Diesel Burn-
er is switched OFF by the VDC/
VAC Control Thermostat, the
following process will take place:
1. The Motor (#2) will shut off
once the three (3) minute
Purge-Cycle has expired.
-THEN-
2. The Aqua-Hot’s Diesel Burner
will automatically turn back ON
once the coolant reaches the preset
temperature of approximately 160
(+/-5) °F
Summary:
The Aqua-Hot’s Diesel-Burner is
operational anytime the operator
moves the Diesel Burner Switch to
the ON position. The Diesel-
Burner will then automatically
maintain the coolant temperature in
the Aqua-Hot’s Boiler Tank with-
out additional involvement from the
operator.
Chart 2