56 | P a g e S V C 8 2 0 ( P ) P o c k e t M a n u a l
56
Explanation: Heat exchanger temperature too low
for more than 3 minutes.
Diagnostic Checks:
Inlet & heat exchanger thermistors
Gas control valve
Water volume control valve
Inlet thermistor Diagnostics:
Go to 31 – Error Code.
Heat Exchanger thermistor Diagnostics:
Go to 32 – Error Code.
Turn power OFF.
Remove connector Rand
measure resistance across #1 wire (Red)
and #2 wire (Black):
40-80 OHMS
Remove connector K. Using the BLACK WIRE
as the common – Individually check resistance for
Yellow, White, Red, & Blue wires:
0.8K – 2.4K OHMS
Continue to diagnostic chart
on next page.
YES
Replace gas control valve.
NO
Connector Location
On Page 14
HINT: High-Efficiency (condensing) Units ONLY:
make sure condensate is draining properly
prior to continuing diagnostics
(go to previous page for diagnostics).
HINT: ALWAYS diagnose thermistors before
continuing to next steps.
To Next Page
Loading...
