Thermo Pride CDX1-100N, Installation And Operation Manual, Page: 48 / 59

All installations and services must be performed by qualified service personnel.
42
DIAGNOSTIC FEATURES
The 50V61 control used on this furnace continuously monitors its operation and the operation of the
system.
If the sensed failure is in the system (external to the control), the red LED will flash in the following flash-
pause sequences to indicate failure status (each flash will last approximately 0.25 seconds, and each
pause will last approximately 2 seconds):
1 flash, then pause
system lockout (retries or recycles exceeded)
2 flashes, then pause low pressure switch stuck closed
3 flashes, then pause low pressure switch stuck open
4 flashes, then pause open high temperature limit switch
5 flashes, then pause not used
6 flashes, then pause 115 V AC power reversed
7 flashes, then pause low flame sense signal
8 flashes, then pause check igniter or improper ground
9 flashes, then pause high pressure switch stuck open
Continuous flash flame sensed with gas valve de-energized
The LED will also flash once at power-up.
A green LED indicator is also present to obtain an estimate of the air flowrate (in CFM) produced by the
house air blower. This LED cycles regularly by providing a constant light, followed by a sequence of
flashes. Each flash can be translated to programmed CFM by using the following:
1 flash per 100(programmed) CFM
: Power must be disconnected before servicing.