User Guide

62
Design Guide - HZH/HZV Series
HZ Series 60Hz
Engineering Specications – Page 3
Option: The unit will be supplied with internally mounted secondary pump for primary/secondary
applications, including one-pipe systems.
Option: The unit shall be supplied with extended range insulation option, which adds closed cell
insulation to internal water lines, and provides insulation on suction side refrigeration tubing
including refrigerant to water heat exchanger.
Option: Unit shall include ClimaDry
®
reheat option. Only modulating reheat that will adjust capacity
based upon supply air temperature to provide “neutral” (72ºF, 22.2ºC) constant air temperature
will be accepted. “Neutral” supply air temperature shall be provided regardless of entering
loop water temperatures (above 55ºF, 12.8ºC) or refrigerant condensing pressures. Control
of reheat must be accomplished via a humidistat or dehumidistat contact closure. Refrigerant
circuit must be AHRI certified. Approved equal manufacturers may provide pre-engineered
integrated modulating hot gas reheat within the unit cabinet, or the installing contractor in
conjunction with the “approved equal” unit manufacturer can provide for approval (during
the submittal phase) an engineered system consisting of: a duct mounted hot water coil,
small circulating pump, modulating control valve, and associated piping using the discharge
condenser water off of the unit as the heating medium. All design costs and costs of field
installed items including additional power wiring to pump, and control wiring to and
from pump and control valve to unit shall be borne by mechanical contractor. Refrigerant
circuitsarenotAHRIcertifiedwhenthereheatoptionisappliedwillnotbeaccepted.
Fan and Motor Assembly:
Blower shall have inlet rings to allow removal of wheel and motor from one side without removing housing. Units shall
have a direct-drive centrifugal fan. The fan motor shall be an ECM variable speed ball bearing type motor. The ECM fan
motor shall provide soft starting, maintain constant CFM over its static operating range and provide airow adjustment
in 25 CFM increments via its control board. The fan motor shall be isolated from the housing by rubber grommets. The
motor shall be permanently lubricated and have thermal overload protection. A special dehumidication mode shall be
provided to allow lower airows in cooling for better dehumidication. The dehumidication mode may be constant or
automatic (humidistat controlled). Airow/Static pressure rating of the unit shall be based on a wet coil and a clean lter in
place. Ratings based on a dry coil, and/or no air lter, shall NOT be acceptable.
Refrigerant Circuit:
All units shall contain an EarthPure
®
(HFC-410A) sealed refrigerant circuit including a high efciency two-stage scroll
compressor designed for heat pump operation, a thermostatic expansion valve for refrigerant metering, an enhanced
corrugated aluminum lanced n and ried copper tube or all aluminum micro channel refrigerant to air heat exchanger,
reversing valve, coaxial (tube in tube) refrigerant to water heat exchanger, and safety controls including a high pressure
switch, low pressure switch (loss of charge), water coil low temperature sensor, and air coil low temperature sensor. Access
ttings shall be factory installed on high and low pressure refrigerant lines to facilitate eld service. Activation of any
safety device shall prevent compressor operation via a microprocessor lockout circuit. The lockout circuit shall be reset at
the thermostat or at the contractor supplied disconnect switch. Units that cannot be reset at the thermostat shall not be
acceptable.
Hermetic compressors shall be internally sprung. The compressor shall have a dual level vibration isolation system. The
compressor will be mounted on specially engineered sound-tested EPDM vibration isolation grommets to a large heavy
gauge compressor mounting plate, which is then isolated from the cabinet base with rubber grommets for maximized
vibration attenuation. All units shall include a discharge mufer to further enhance sound attenuation. Compressor shall
have thermal overload protection. Compressor shall be located in an insulated compartment away from air stream to
minimize sound transmission.