Rheem 64DV Troubleshooting Manual page 79

78 | P a g e S V C 8 2 0 ( P ) P o c k e t M a n u a l
Explanation: Water by-pass valve malfunction.
Diagnostic Checks:

Water bypass valve
Turn Power OFF. Remove
and reinsert connector B .
Remove control board
bracket (How to Remove:
Section 1). Visually inspect
water bypass valve for loose
or damaged connections.
Reassemble & operate unit.
Does 66 – Error Code
appear?
Turn remote control OFF;
unplug unit. Plug unit in.
Turn Power ON. Operate
unit. Check DC volts across
Red & Black wires at
connector B :
8 – 16 DC Volts
Operate unit.
IF 66 – Error Code appears:
Replace water bypass valve.
78
66 – Error Code
NO
NO
Connector Location
On Page 14
Unit had a loose connection.
Unit appears to be operating
OK
Check connector B .
Operate unit again.
IF 66 – Error Code appears:
Replace control board.
For water bypass valve
location: Refer to 65 -
Error Code diagram.
Water bypass valve is
located right of blower
motor; connected directly
to bottom of two copper
pipes.