50A52 Flow Chart 1 - American Standard *UD Series Operation Manual

50A52 Flow Chart 1

Indoor Blower
Check
Place
Thermostat in
Fan On (G)
1A
YES
Does Indoor
Blower Run
Cool Speed?
NO
1B
Is 24 VAC Present
R&C Terminals?
YES
Is 24 VAC Present
G and B/C Terminals?
YES
Is 120 VAC Present
Across Cool and
CIRC NEUT Terminals?
YES
Check Blower Motor
and Wiring
Return Fan
Switch to Auto
Position
NO
Is 120 VAC Present
Control Terminals
XFMR & XFMR NEU?
Check 120 VAC
NO
Source
Check T-Stat and
Low Voltage Wiring?
NO
Replace
Control
Chart 4
YES
Is 24 VAC Present
at TH and TR
Terminals?
NO
Replace
Control
61
NO
Replace
Transformer
YES