Frost Protection; Flow Switch (Units Without Hydraulic Module) - Carrier AquaSnap 61WG Series Installation, Operation And Maintenance Instructions

9 - WATER CONNECTIONS
Condenser water loop (61WG/30WG)
Evaporator water loop (61WG/30WG/30WGA)
Components of unit and hydraulic module
1 Victaulic screen filter (option 293 or 293A only)
2 Expansion tank (option 293 or 293A only)
3 Safety valve (option 293 or 293A only)
4 Water pump
5 Air vent
6 Water drain valve
7/8 Entering/leaving pressure sensor
9/10 Entering/leaving temperature probe
12 Flow switch 61WG option 272 (sizes 020-045 only)
13 Compressor
14 Evaporator
15 Condenser
16 Expansion device
NOTE: Units without hydraulic module include a flow switch.

9.3 - Frost protection

The units are designed to be installed under cover at outside
temperatures between +5 °C and +40 °C. Therefore they do not
include anti-freeze protection, as standard.
If the water piping is in an area where the ambient tempera-ture
can fall below 0 °C it is recommended to install a trace heater on
the piping and to add an antifreeze solution to protect the unit and
the water piping to a temperature of 10 K below the lowest
temperature likely to be reached at the installation site.
Use only antifreeze solutions, approved for heat exchanger duty.
If the system is not protected by an antifreeze solution and will
not be used during the freezing weather conditions, draining of
the cooler and outdoor piping is mandatory. Damage due to
freezing is not covered by the warranty.
IMPORTANT: Depending on the climatic conditions in your
area you must:
- Add ethylene glycol with an adequate concentration to
protect the installation up to a temperature of 10 K below
the lowest temperature likely to occur at the installation site.
- If the unit is not used for an extended period, it is
recommended to drain it, and as a safety precaution add
ethylene glycol to the heat exchanger, using the heat
exchanger water entering purge valve connection.
- At the start of the next season, refill the unit with water
and add an inhibitor.
48
Typical water piping diagram, units with hydraulic modules
2
1
Unit water inlet
3
Unit water outlet
2
1
Unit water inlet
3
Unit water outlet
12
4 5
PT
TT
7
9
6
TT PT
10 8
6
4
5
PT TT
7 9
6
TT PT
10 8
6
- For the installation of auxiliary equipment, the installer
must comply with basic regulations, especially for
minimum and maximum flow rates, which must be
between the values listed in the operating limit table
(chapter 5 - "Application data").
To avoid corrosion by differential aeration, the complete heat
exchange circuit must be charged with nitrogen, if it is drained for
longer than one month. If the heat exchange fluid does not comply
with the manufacturer recommendations, the circuit must
immediately be filled with nitrogen.

9.4 - Flow switch (units without hydraulic module)

IMPORTANT: the unit water flow switch must be energised,
and the chilled water pump interlock must be connected.
Failure to follow this instruction will void the manufacturer's
guarantee.
The flow switch is supplied, installed on the evaporator leaving
water pipe and preset at the factory to cut out when there is
insufficient water flow.
Terminals 34 and 35 are provided for field installation of the chilled
water pump interlock (auxiliary contact for pump operation to be
wired on site).
15
13
16
14