York 120 User Manual

Subject to change without notice. Printed in U.S.A.

035-17311-002-A-0803

Copyright

 ©

 by Unitary Products Group 2003. All rights reserved.

Supersedes: 035-17311-001-A-1202

terminal.  If 24 volts is not present, check for loose wiring 
from the Y1 “OUT” terminal to the Mate-N-Lock plug, a 
poor connection between the UCB and economizer 
Mate-N-Lock plugs, loose wiring from the Mate-N-Lock 
plug to the economizer, back to the Mate-N-Lock plug, 
and from the Mate-N-Lock plug to the Y1 “ECON” 
terminal.  The economizer control may have faulted and 
is not returning the 24 volts to the Y1 “ECON” terminal 
even though the economizer is not providing free 
cooling.  To test the economizer control, disconnect the 
Mate-N-Locks and jumper between the WHITE and 
YELLOW wires of the UCB’s Mate-N-Lock plug.

13. The UCB can be programmed to lock out compressor 

operation during free cooling and in low ambient condi-
tions. These options are not enabled by default. They 
can be checked by local York distributors.

14. If none of the above corrected the error, test the integrity 

of the UCB.  Disconnect the C1 terminal wire and jumper 
it to the Y1 terminal.  DO NOT jump the Y1 to C1 termi-
nals.  If the compressor engages, the UCB has faulted.

15. If none of the above correct the error, replace the UCB.