York YCAQ10, Руководство пользователя, Страница: 76 / 99

Proud Sponsor
of the 1998
U.S. Olympic Team
36USC380
P.O. Box 1592, York, Pennsylvania USA 17405-1592 Subject to change without notice. Printed in USA
Copyright © by York International Corporation 1997 ALL RIGHTS RESERVED
Form 150.40-NM20 (597)
Supersedes: 150.40-NM20 (587)
SMART PANEL EQUIPPED
LCH & YCHA RECIPROCATING CHILLERS
MIS-DIAGNOSING INCORRECT SERVICE VALVE
POSITIONING AS TRANSDUCER FAILURES
Recently we have been made aware that transducers mounted on Service valves have been sometimes mistakenly
diagnosed as being defective. It was later found that the transducer’s output was wrong because the transducer had
been valved off due to incorrect Service valve positioning.
Be sure, after replacing a transducer or when starting a new chiller where the Service valves have been placed in the
front-seat position to close off the system, that you back-seat all Service valves completely and then turn them one
turn toward the front seat position to assure that the transducers are not valved off. This should also be checked
when troubleshooting. In the past, we have found the customer’s maintenance people have occasionally valved off
transducers by mistake.
SUBJECT: WARNING - BLACK PLASTIC MICROBOARD COVER IS CONDUCTIVE
The earlier version, “rotary dial” type micropanel recip chillers contained a black plastic cover which fit over the
microboard, and was secured in place by the hardware on the four bat-handle toggle switches on the microboard.
You should be aware that these black plastic panels are coated inside with a conductive compound. This is intended
to be a barrier against RFI-EMI emissions.
Because of this conductive coating, you should treat this panel as if it were made of metal. Do not place this cover
inside the power panel of the chiller when doing service. The coated surface could get against the chiller’s power
lugs and cause a short circuit. Even worse is that the plastic could melt and ignite, creating a fire inside the power
panel.