Fluid Circulation Pump
©Aqua-Hot®
250-D03 Diesel Series Service Manual
REV 220302
p. 36
AC Electric System
AC Relay
Introduction:
The AC relay is an electrical device where the DC circuit from the
controller determines whether the AC power is permitted to flow
to the electric heating element. This allows the controller to turn
the electric heating element on and off in conjunction with the
interior control panel and ETS module even though the electric
element is on a separate circuit.
Troubleshooting Procedure:
Troubleshoot the AC relay if the electric element fails to operate.
The following conditions must be met before the AC relay can
be diagnosed:
•
The fluid expansion bottle is filled to at least the COLD
line.
• All in-line fuses are functional
• The Aqua-Hot is completely cool
• DC electrical power is supplied to the Aqua-Hot
• AC electrical power is supplied to the electric element
• All thermostats are in working order
Correct any conditions above before continuing with
troubleshooting. Results of the troubleshooting procedure
cannot be verified if the conditions above are not fulfilled.
1. Locate the AC wires connected to the AC relay and remove
the wires from the relay.
2. Using an ohmmeter, check the AC relay pins for continuity.
3. If no continuity exists, follow replacement procedure to
replace the AC relay.
AC Relay Replacement Procedure:
If it has been determined that the AC relay needs to be replaced,
follow the outline below to replace the AC relay.
4. Ensure that the Aqua-Hot has been completely shut down
and all power sources have been disconnected. Be sure the
boiler tank is completely cooled.
5. Ensure that the coach is not connected to shore power and
that a generator is not connected during this procedure.
6. Remove the AC access cover to gain access to the relay.
See Figure 60.
7. Remove all wires from the relay.
8. Remove the defective relay by drilling the rivets that hold
the relay in place and discard the defective relay.
9. Rivet the replacement AC relay in place.
Remove this cover
Figure 60
AC Relay
Figure 61
10. Using the wiring diagram on Page 100, connect the wires
previously removed to the replacement relay.
11. Test for normal operation.
