present, trace the wiring from Y1 “OUT” for incorrect wir- ing. If 24 volts is not present at the Y1 “OUT” terminal, the UCB must be replaced.
12.For units without economizers: If 24 volts is present at the Y1 “OUT” terminal, check for 24 volts at the Y1 “ECON” terminal. If 24 volts is not present, check for loose wiring from the Y1 “OUT” terminal to the
For units with economizers:If 24 volts is present at the Y1 “OUT” terminal, check for 24 volts at the Y1 “ECON” terminal. If 24 volts is not present, check for loose wiring from the Y1 “OUT” terminal to the
test the economizer control, disconnect the
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 distributors.
For units with factory installed economizers, the UCB is programmed to lock out compressor operation when the LAS set point is reached.
For units without factory installed or with field installed economizers, the UCB allows compressor operation all the time. This programming can be checked or changed by the local distributor.
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.
Subject to change without notice. Printed in U.S.A. | |
Copyright © 2006 by Unitary Products Group. All rights reserved. | Supersedes: |
Unitary | 5005 | Norman |
Products | York | OK |
Group | Drive | 73069 |