Johnson Controls YORK PYT 0330 Instruction Manual page 10

Introduction
Johnson Controls has a long history of technology development, for example in the area of variable
speed drives. With the advancement in efficiency and power density comes increased demands on
the cooling systems incorporated onto our chillers and drives.
YORK chiller variable speed drives cooling systems require inhibited water to minimize corrosion
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and biological growth, both of which can occur in untreated coolant loops. As with any technology,
these chemical treatments have evolved over time as our understanding of how the heat and
cooling cycles of the inhibitor impact other drive components within the drive.
Johnson Controls has engineered and developed specialized proprietary coolant inhibitor for your
liquid-cooled starter or variable speed drive. Failure to use this proprietary inhibitor may result in
component damage.
How to use this document
Due to service requirement changes, only the service instructions in this manual must be used to
service all YORK liquid-cooled drive or LCVSD, PYT, HYP, or liquid-cooled solid state starter (LCSSS)
coolant service intervals. These instructions may require you to refer to the traditional low voltage
variable speed drive (LVVSD) or LCSSS manuals. See
See Inhibitor loop service guidelines and flowcharts
flowcharts beginning with
Read this entire document before starting service on the drive or starter to ensure the correct
instructions are followed.
Inhibitor loop service guidelines and flowcharts
All drive coolant loops have requirements for service at commissioning and at annual intervals. All
Johnson Controls liquid-cooled drive cooling loops use the Johnson Controls light blue coolant. See
the following sections for the requirements and steps to take during site visits:
• Servicing requirements
• Servicing requirements during any service or review of the chiller
• HYP model drives normal operation with no additional service required
• HYP model drives operational indications that require additional service
Servicing requirements
• Commissioning requirements:
- Change the shipping fluid from glycol mixture to the light blue inhibitor as outlined in Step
1, Step 2, and Step 3 of
loops.
• Annual requirements:
- Change the current coolant with light blue inhibitor as outlined throughout
flush, fill, and vent PYT and HYP model drive coolant
- Inspect and clean the drive HX tubes. This is a critical step that you must always complete
when you are servicing the drive coolant loop.
-
Note: Service parts for the annual service requirements can be purchased as kits that
contain all of the necessary materials to completely service your liquid-cooled variable
speed drive or starter. Refer to SI0583.
10
Figure 1 for additional steps during the service of all coolant loops.
How to drain, flush, fill, and vent PYT and HYP model drive coolant
Chillers with YORK Liquid-Cooled Variable Speed Drives and Starters
© 2025 Johnson Controls. All rights reserved.
Associated literature.
for the required service steps. See the
loops.
How to drain,