Check Valves - Aqua-Hot 400 Series Service Manual

Check Valve:
Check Valves are installed into the zone outlet ports for
each heating loop to ensure that the antifreeze and water
heating solution only flows in one direction. If the heating
solution attempts to backflow into the boiler tank, the check
valve closes to prevent that from happening.
Troubleshoot the check valves if the following condition has
occurred:

There is a lack of interior heat in a particular zone.
Troubleshooting:
1. Verify that the heating zone is operating properly by
checking the following:

Check the electronic controller to insure that both the
"Heating Zone Status" and corresponding pump status
("Pump #1 or "Pump #2") indicator lights are illuminat-
ed GREEN.

Check the circulation pump for operation by holding the
pump and feeling vibration.
2. With the circulation pump operating, tap on the check
valve and wait five minutes to evaluate.
If the interior heat is present after tapping the check valve,
the check valve was stuck closed and no further action is
necessary.
3. Check the Aqua-Hot's antifreeze and water heating solu-
tion's ratio of water to propylene glycol boiler antifreeze.
This mixture ratio should be approximately 50/50. If the
solution is fully antifreeze (100%), the check valves will
continue to stick.
NOTE: Storing the motor home for an extended period of
time can cause the check valves to stick. If, after the initial
release of the stuck check valves it continues to stick, fol-
low the instruction in this section to replace the check
valve.
Valves
Replacement Procedure:
Failure to disconnect all power supplies 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 disconnect-
ed. Also, because this replacement procedure will in-
volve 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. Using constant tension pliers, loosen and slide back the
constant tension clamp securing the hose to the defec-
tive valve.
4. Remove the hose from the defective check valve.
5. Unscrew the defective check valve from the Aqua-Hot's
boiler tank.
6. Remove the hose barb and the 1/2 inch coupler from
the defective check valve.
7. Clean the hose barb and coupler, then wrap the hose
barb and the 1/2 inch coupler pipe threads with thread
seal tape.
8. Install the hose barb and 1/2 inch coupler on the re-
placement check valve, ensuring that they are installed
properly with the hose barb on the arrow side of the
check valve.
9. Install the replacement check valve onto the Aqua-Hot's
boiler tank. The arrow on the check valve must point
away from the boiler tank.
10. Slide the hose onto the check valve and set the con-
stant tension clamp back into place.
11. Refill the Aqua-Hot's boiler tank with the antifreeze and
water heating solution. Reference appendix D for
proper filling procedure.
Figure 17
Zone Check Valve
© Aqua-Hot® AHE-400-P01 Service Manual Rev.B June 2014
Section #: Title
Aqua-Hot Components
p.
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