McQuay WGS130AA: WGS140AW, Руководство по эксплуатации

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OM WGS-5 WGS 130A to 190A 43
The Remote ICE Mode Switch (usually a time clock) is a field installed option and is used
to switch from
ice mode operation at night to cooling mode operation during the day. This
requires that the Control Source be set to SWITCHES, which in this case refers to the
Remote ICE Mode Switch.
There are really only three operational modes for the unit, although they can be used in
combination:
1. COOL, the unit unloading and compressor staging is controlled by the Active LWT
Setpoint. COOL w/ Glycol is a special case, providing for lower setpoint ranges.
2. ICE, the unit runs with all compressors fully loaded until the LWT (set for making ice)
is reached, and the unit shuts off. The Ice Delay Timer can be set to prevent restarting
until the next ice making cycle.
3. TEST, manually energize controller outputs to test functionality.
Unit Test Mode
The unit test mode allows manual testing of controller outputs. Entering this mode shall
require the following conditions.

Unit OFF input = OFF (i.e. entire chiller is shut down).

Technician password active.

Available Circuit Mode setpoint = TEST
A test menu can then be selected to allow activation of the outputs. It shall be possible to
switch each digital output ON or OFF and set the analog outputs to any value.
Unit States
The unit will always be in one of three states.
Power ON
OFF
PUMPDOWN
AUTO
T1
T4
T2
T3
Unit States
Transitions:
T1 – Transition from Off to Auto
Requires all of the following

Unit enabled based on settings and switches

If unit mode is ice, the ice timer has expired

No unit alarms exist

At least one circuit is enabled and available to start
T2 – Transition from Auto to Pumpdown
Requires any of the following

Control source is keypad and the unit enable keypad setting is “off”

Control source is BAS and either the remote switch is “off” or the BAS command is
“off”

Control source is switches and the remote switch is “off”