Service manual

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© January 2013 Aqua-Hot
®
600-D01 Series Hydronic Heating System Service Manual - Rev. A
Thermostats
Control Thermostat:
The control thermostat is installed into the Aqua-Hot’s boiler
tank and monitors the temperature of the antifreeze and water
heating solution to determine when it is at operating temperature
and when it requires heat. The Aqua-Hot is considered to be at
operating temperature between 158°F and
190°F.
Troubleshoot the control thermostat if one of the following con-
ditions has occurred:

There is a lack of hot domestic water and interior heat.

The heating Status light does not illuminate on the electron-
ic controller, when the Aqua-Hot is below 158° F.

Excessive Blue or white smoke is expelled from the
exhaust.
Troubleshooting:
1.
Turn the diesel-burner and electric element switches on the
interior switch panel on and check the electronic controller
to ensure that the “Electric Heating Element Status” and
“Diesel-Burner Status” indicator lights are illuminated.
2. Verify that the “Heating Status” indicator light on the elec-
tronic controller is illuminated, as it should be whenever the
Aqua-Hot is below the operating temperature range of
158°F.
If the “Heating Status” indicator light is not illuminated,
check the following:
A.
Verify that the temperature of the boiler tank has fallen
below the 158°F minimum operating temperature by
checking with a digital thermometer.
B.
Disconnect the control thermostat’s wires from their
connections, and, using a digital voltage meter, check
for continuity.
If there is no continuity, follow the instructions in this
section for replacing the Control Thermostat.
If continuity exists, complete the following:
a.
Inspect the control thermostat’s wiring and con-
nections.
b.
Install a jumper wire on the JP3 plug, between
pins 13 and 14 (“TSTAT-I” and “TSTAT-O”) on
the electronic controller in order to bypass the con-
trol thermostat.
NOTE:
The diesel-burner and/or electric element switch must
be in the on position, for the “Heating Status” indicator
light on the electronic controller to illuminate.
If the “Heating Status” indicator light on the electronic
controller does not illuminate with the jumper wire
installed, follow the instructions in this manual to re-
place the electronic controller.
If the “Heating Status” indicator light is illuminated, But the
diesel burner fails to operate: check the following:
1. Verify the diesel burner’s control thermostat wires
are properly connected, and that there are no loose
wires, both at the diesel burner and at the JP4 plug,
on the Electronic Controller.
2. Using a DC Voltmeter Verify both the
C1 (Orange - #22)and the C7 (White - #23) Wires,
on the Electronic Controller’s JP4 Plug have 12VDC.
If the C7 (White - #23) Wire does not have 12VDC, and
both the Diesel Burner Status Light and the Heating Status
lights are illuminated, the electronic controller will need to
be replaced.
If the C1 (Orange - #22) wire does not have 12VDC Refer
to the Webasto Diesel Burner Controller Troubleshooting, in
section 9.
Control Thermostat Replacement Procedure:
FAILURE TO DISCONNECT ALL POWER SUPLIES AND/OR TO
ALLOW THE HEATER TO COOL BEFORE SERVICING COULD
CAUSE SERIOUS DAMAGE OR PERSONAL INJURY.
1.
Ensure that the Aqua-Hot has been completely shut down
and that all power sources have been disconnected. Also,
because this replacement procedure will involve the boiler
tank and the potential for hot coolant, be sure the heater has
adequately cooled.
2.
Drain the antifreeze and water heating solution from the
Aqua-Hot’s boiler tank using the drain valve.
3.
Disconnect the defective control thermostat’s wires by sep-
arating the quick-disconnect terminals.
4.
Using a 7/8 socket, unscrew the control thermostat from the
Aqua-Hot’s boiler tank.
5.
Wrap the threads of the replacement control thermostat with
Teflon tape.
SECTION 4: AQUA-HOT COMPONENTS