Rheem 64DV Troubleshooting Manual page 95

94 | P a g e S V C 8 2 0 ( P ) P o c k e t M a n u a l
90 & 99 – Error Code
Explanation: Unit was operated prior to vent
installation OR unit detected blockage in the venting
during pre-purge OR post-purge cycle.
90 – Error Code will occur BEFORE unit goes to
ignition.
99 – Error Code will occur AFTER unit shuts down.
Unit must be reset by performing reset procedure
on page 26.
Diagnostic Checks:

Perform reset procedure on page 26

VENTING – refer to pages 8-11 or refer to
Use & Care manual for installation
instructions:
1. Approved vent materials
2. Approved terminations
3. Approved vent lengths
4. Location and distance between venting
5. Blocked venting
6. Venting not sealed properly
94
(recirculation of exhaust)
(recirculation of exhaust)