Error Code 65 (Rtg66 Only); Code 65 Water Volume Control Fault - Rheem RTG2-42 Troubleshooting Manual

The water heater appears to be
normal. Attempt to operate
again.
Replace Printed Circuit Board

Error Code 65 (RTG66 Only)

Explanation: Water Volume Control fault. At a minimum check the following:
1. Verify there is water flow thru the unit even if the unit does not fire.
2. Access maintenance information to determine flow rate.
3. Check all wiring connections to the water control and connector B on the Printed Circuit
Board.
Turn power off;
unplug unit and
then on again.
When motor
operates, is the
voltage to the
water control
OK?
Replace the Water Control Assembly
Is there any
pulse output
from the Fan
Motor?
Yes
Is the voltage to
the water
control OK?
Yes
No
Replace the Printed Circuit Board
Measure the voltage at connector C between the White#2 and
Black#8 wires for: 8 to 16 VDC
32
SVC 810 Tankless Troubleshooting Manual
No
Is there any pulse output from the
Fan Motor? To measure the pulse
output, turn on the fan by pushing
"MAX" (SW2) Button. Measure the
voltage of connector G between
Blue and Yellow wires:
4 to 10 VDC (pulse)
No
Replace the Printed Circuit Board
Measure the voltage at connector C between the
Red#7 and Black#8 wires for:
Replace Fan Assembly
8 to 16 VDC