Owners Manual

Manufacturer of Quality Air Conditioning and Heating Products • www.islandaire.com • [e-mail] • (800)-886-2759
47
Performance Specifications (cont.)
G. Protection Circuits:
Compressor shall have automatic reset, over tempera-
ture and over current protection. e fan motor shall
have an inherent, automatic reset over temperature
protection. e electric heater shall have two over
temperature protectors.
4.0.1 HEAT PUMP OPERATION
Heat pump units shall have the selected room tempera-
ture maintained by cycling either in the heat pump mode
or electric strip heat. A heat pump unit with electric heat
is switched from the heat pump mode to electric strip
heat when the outdoor coil temperature is 20 °F or when
the heat pump cannot keep up with the heating load and
a two-stage thermostat is used.
For heat pump operation, a room thermostat with a B**
(heating changeover) terminal is required. is will
mean that some “auto changeover” thermostats cannot
be used, as many of them either do not have a B** termi-
nal, or else energize the B** terminal continuously when
in the “auto” position.
4.0.2 ELECTRIC HEAT OVERRIDE
For heat pump applications, electric heat comes on only
when the outdoor coil temperature is below
28 °F, maximizing the amount of time the unit operates
in the more ecient heat pump mode. e minimum
COP for heat pumps, at 47 °F DB outdoor, must be 2.9
for all sizes.
(Heat pump models shall also include reversing valve).
4.0.3 REVERSE CYCLE
A Heat Pump WITH back-up electric heat –
e reversing valve, the compressor, the outdoor con-
denser fan motor and the indoor fan motor shall be
energized. Reverse cycle heating shall occur when the
outdoor coil temperature is
28 °F and above. If outdoor coil temperature drops
below 28 °F or the Outdoor air temperature drops to
35 °F or less, electric heat is the only source of heat.
When the outdoor coil temperature rises back to 40 °F
or above, the Compressor or electric heater is used.
A temperature-sensing device shall be used to moni-
tor the outdoor coil temperature to limit frost buildup.
Defrosting of the outdoor coil will be activated when
outdoor coil temperature drops below 28 °F or out-
door air temperature drops to 35 °F or less. Defrost-
ing is terminated when outdoor coil temperature rises
back to
40 °F. During defrosting, both compressor and the
outdoor fan are turned o. e indoor fan will run at
its set speed.
Condensation accumulated during reverse cycle heat-
ing must NOT be evaporated against the indoor coil
so as to prevent contamination of the indoor air with
pollutants and odors. Condensation must be disposed
of using a (external/internal) drain system as shown
on plans.