Product Manual ALR2-3 ALR 110F – 150F 39
Evaporator Freeze Protection
Evaporator freeze protection can be a concern in the application of air-cooled water chillers. To protect
against freeze-up, insulation and an electric heater cable are furnished with the unit. This protects the
evaporator down to -20°F (-29°C) ambient. Although the evaporator is equipped with freeze
protection, it does not protect water piping external to the unit or the evaporator if there is a power
failure or heater cable burnout. Consider the following recommendations for additional protection.
1. If the unit will not be operated during the winter, drain evaporator end chilled water piping. Drain
and vent connections are provided on the evaporator to ease draining.
2. Add a glycol solution to the chilled water system to provide antifreeze protection. Freeze point
should be approximately ten degrees below minimum design ambient temperature.
The evaporator heater cable is wired to the 115 volt circuit in the control box. This power should be
supplied from a separate source, but it may be supplied from the control circuit. Operation of the
heater cable is automatic through the ambient sensing thermostat that energizes the evaporator heater
cable for protection against freeze-up. Unless the evaporator is drained in the winter, the disconnect
switch to the evaporator heater must not be open.
Coil Material/Coating
The correct choice of fin material or selection of a coating can have a dramatic effect on the life and
efficiency of the coil when corrosive or abrasive material is present. McQuay offers a variety of coil
options to satisfy most ambient conditions.
Aluminum Fin
Lanced (slotted) 16 fpi aluminum fin is the standard fin material. It is used in non-corrosive, non-
abrasive applications. Tubes are copper and completely covered by the fin shoulders on the face of
the coil.
Copper Fin
Optional copper fins are a solid ripple fin design, 18 fpi. Tubes are copper and completely covered by
the fin shoulders on the face of the coil. Copper fin provides good coil protection against chemicals
that do not affect copper and is widely used in salt spray applications.
Black Fin
Optional Black Fin is aluminum finstock precoated with a 0.06 to 0.12 mil thick phenolic epoxy coating.
It is a low cost solution for certain corrosive applications including salt spray. Passes 1000 hour salt
spray test per ASTM B117.
ElectroFin™ Coating
Optional ElectroFin™ is a flexible dip and baked epoxy coating applied to the coil and coil frame after
the coil is fabricated and prior to the coil being installed in the unit at the factory. It can be used on
both aluminum and copper fins. The entire coil, including the fin edges, is covered with a uniform
coating. There is no bridging of the fin slots. This coating is resistant to a wide range of chemicals
including salt spray. It cannot be applied in the field after a unit is manufactured. Passes 3000 hour
salt spray test per ASTM B117. Meets MIL-P-53084 (ME). It is resistant to the following chemical
fumes among many others:
Acetone
Carbon Tet
Fluorine Gas
Kerosene
Oleic Acid
Sucrose
Ammonia
Chlorides
Gasoline
Lactic Acid
Ozone
Sulfates
Benzene
Chlorine Gas
Glucose
Methanol
Phosgene
Sulfides
Boric Acid
Citric Acid
Glycol
Napthol
Salt Water
Sulfites
Butyl Alcohol
Diesel Fuel
Hydrofluoric Acid
Isobutyl Alcohol
Oxaloc Acid
Urea
CaCl
2
Ethyl Acetate
Hydogen Sulfide
Methyl Ketone
NaCl
Vinegar
To Next Page
Loading...
Need help?
General
