Recycle Control; Running Timers And Counters - Carrier SmartVu Control Manual

5.16.

Recycle Control

Recycle Mode — The chiller may cycle off and wait until the load is increased to meet restart
requirements when the compressor is running in a lightly loaded condition. This cy cling is normal and is
known as "recycle." A recycle shutdown is initiated when any of the following conditions are true:
Cooling Mode
- Leaving chilled water temperature (or entering chilled water temperature, if the EWT CONTROL
OPTION is enabled) is more than 5° F (2.8° C) below the CONTROL POINT.
- Leaving chilled water temperature (or entering chilled water temperature, if the EWT CONTROL
OPTION is enabled) is below the CONTROL POINT, and the chilled water temperature difference is
less than the RECYCLE SHUTDOWN DELTA T.
Heating Mode
- Leaving condenser water temperature (or entering condenser water temperature, if the EWT
CONTROL OPTION is enabled) is more than 5° F (2.8° C) above the CONTROL POINT.
- Leaving condenser water temperature (or entering condenser water temperature, if the EWT
CONTROL OPTION is enabled) is above the CONTROL POINT, and the condenser water
temperature difference is less than the RECYCLE SHUTDOWN DELTA T.
NOTE: Recycle shutdown will not occur if the CONTROL POINT has been changed by more than
one degree F within the previous 5 minutes of operation.
When the chiller is in RECYCLE mode, the chilled water pump relay remains energized so the chilled
water temperature can be monitored for increasing load. The recycle control uses RECYCLE RESTART
DELTA T to check when the compressor should be restarted. The compressor will restart when the
chiller is:
Cooling Mode
- Leaving chilled water temperature (or entering chilled water temperature, if the EWT CONTROL
OPTION is enabled) is greater than the CONTROL POINT plus the RECYCLE RESTART DELTA T
f or 5 consecutive seconds.
Heating Mode
- Leaving condenser water temperature (or entering condenser water temperature, if the EWT
CONTROL OPTION is enabled) is less than the CONTROL POINT minus the RECYCLE RESTART
DELTA T f or 5 consecutive seconds.
5.17.

Running Timers and Counters

19 Series Carrier® SmartVu
COMPRESSOR CONTINOUSE ONTIME and SERVICE ONTIME. COMPRESSOR ONTIME indicates
the total lifetime compressor run hours. SERVICE ONTIME is a resettable timer that can be used to
indicate the hours since the last service visit or any other event. A separate counter tallies compressor
starts as TOTAL COMPRESSOR STARTS. COMPRESSOR CONTINOUSE ONTIME shall start from
statt complete and cleared after stop complete. All of these can be viewed on the RUN TIMES screen on
SRDC-UG-2-14-000
19 Series Carrier®
TM
SmartVu
Controls IOM
TM
control maintains three run time clocks: COMPRESSOR ONTIME,
REVISION
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2.3
DATE PAGE
Dec 4, 2020 83 OF 168
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