Maintenance; General Requirements; Daily Maintenance; Unit Status - York YGWH 115 Installation, Commissioning & Operation

7.

Maintenance

General Requirements

The units have been designed to operate continuously
provided they are regularly maintained and operated
within the limitations given in this manual. Each unit
should be included in a routine schedule of daily
maintenance checks by the operator/customer, backed
up by regular service inspection and maintenance visits
by a suitably qualified Service Engineer.
It is entirely the responsibility of the owner to provide
for these regular maintenance requirements and/or
enter into a maintenance agreement with a Johnson
Controls service organisation to protect the operation
of the unit. If damage or a system failure occurs due
to improper maintenance during the warranty period,
Johnson Controls shall not be liable for costs incurred
to return the unit to satisfactory condition.
This maintenance section applies to the basic
unit only and may, on individual contracts, be
supplemented by additional requirements to
cover any modifications or ancillary equipment
as applicable.
The Safety Section of this manual should
be read carefully before attempting any
maintenance operations on the unit. This
section should be read in conjunction with
the Unit Operation Section.

Daily Maintenance

The following maintenance checks should be carried
out on a daily basis by the operator/customer. Please
note that the units are not generally user serviceable
and no attempt should be made to rectify faults or
problems found during daily checks unless competent
and equipped to do so. If in any doubt, contact your
local Johnson Controls Service Centre.
Operating conditions: Read the operating pressures
and temperatures at the control panel check that
these are within the operating limitations given in the
Operating Instructions Manual.

Unit Status

Using the keypad check the fault screens to ensure no
fault are displayed.
EN
Form 6S6I-B01C-EOMA-EN (0318)

Refrigerant charging and leak checking

Refrigerant leaks checking
Periodic refrigerant leak checking must be part of a
comprehensive maintenance program. Leak check the
entire chiller using a calibrated electronic leak detector.
Confirm leaks with soap bubbles that are found using
the electronic leak detector. Check refrigerant relief
valve piping and tube rolled joints as part of the
comprehensive refrigerant leak checking program.
Repair leaks before adding refrigerant. Visually check
the heat exchangers, compressors and pipework for
damage and gas leaks.
Determining correct refrigerant charge level
The refrigerant charge level is correct when the
measured evaporator
superheat are within the values listed in the table below.
Liquid refrigerant will be visible in the evaporator
sight glass. The refrigerant level cannot be properly
determined by viewing the liquid refrigerant level in the
evaporator sight glass.
All YGWH units Form 1 shipped are charged with the
correct amount of refrigerant. Under some operating
conditions the chiller may appear to be overcharged
or undercharged with refrigerant. Consult with YORK
Factory prior to removing or adding refrigerant.
Definitions
Evaporator approach= (L.E.L.T) - (S.E.T)
Discharge superheat= (C.D.G.T) - (S.C.T)
When:
L.E.L.T = Leaving Evaporator Liquid Temperature
S.E.T = Saturated Evaporator Temperature
C.D.G.T = Compressor Discharge Gas Temperature
S.C.T = Saturated Condensing Temperature
Refrigerant Charge
Should it become necessary to add refrigerant charge
to a YORK YGWH Chiller; add charge until the
evaporator approach and refrigerant gas discharge
superheat are within the values listed in the following
table:
Condition
Evaporator Approach
Discharge Superheat
A charging valve is located in the liquid line below the
evaporator. The size of the charging connection is
1/4 inch male flare. Purge air and non-condensables
from the charging hose. Only add new refrigerant, or
refrigerant that has been tested and certified to meet
American Refrigeration Institute Standard (ARI-700).
approach and discharge
R134a
1.1°C ~ 2.5°C
7.0°C ~ 10.0°C
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