Three-Way Valve
©Aqua-Hot®
250-D03 Diesel Series Service Manual
REV 220302
p. 29
• If the hose is hot not to the touch while hot water is
running, replace the three-way valve.
• Grab the other hose highlighted green as shown
below. While hot water is running, these should be
cool. If not cool while hot water is running, replace
the three-way valve.
5. If the three-way value does not actuate, locate the J6
plug and test for voltage between pins J6-10 and J6-11.
• If no voltage at these pins, replace the controller.
6. If there is voltage, leave the probes of the multimeter in
place and go back to the LCD screen. Navigate to the
TEST page and tap NEXT.
7. Tap THREE-WAY VALVE to actuate the three-way valve
and check the multimeter.
• If the voltage polarity measured by the meter
inverts, replace the three-way valve.
• If it does not invert, replace the controller.
Three-Way Valve
Introduction:
The Aqua-Hot has a three-way directional valve to control
coolant priority within the unit. This ensures that there will be
a supply when heated water is being called for, but can provide
interior heating when the need arises.
Troubleshooting Condition:
Troubleshoot the three-way valve if the following conditions
have occurred:
• An absence of interior heat
• Inconsistent or complete lack of hot water
Troubleshooting:
1. Verify the following before troubleshooting the three-way
valve:
• The ETS module is calling for heat
• The interlock switch is depressed
•
The overflow bottle is adequately filled
• The high-limit thermostats are not tripped
• There are no faults on the LCD screen/control panel
2. Verify that the heating zone is operating properly by
checking the hoses to see if they are hot to the touch
when a heating zone is calling for heat.
3. Locate the LCD screen. Navigate to the TESTING page
(Figure 46).
• Tap NEXT, and then select THREE-WAY VALVE. The
three-way valve should begin to actuate. This can
be heard outside the cabinet.
4. If the three-way valve actuates, activate the burner/
electric and allow the heater to heat to temperature.
• Open a hot water faucet and grab the hose
highlighted green as shown below. While hot water
is running, it should be hot to the touch.
Figure 46
Figure 45
Figure 47
Three-Way Valve
