exchanger shall be tested and rated for 3102 kPa 450 psi
refrigerant working pressure. A parallel capillary tube/thermal
expansion valve assembly shall provide superheat over [one to 43
degree C30 to 110 degree F] [7 to 32 degree C45 to 90 degree F]
liquid temperature range. Refrigerant-to-water heat exchangers
and refrigerant piping shall be insulated to prevent condensation
on the piping containing low temperature water.
[e.
Factory-Installed Domestic Hot Water Desuperheater: Provide
desuperheater of vented double-wall construction and factory
installed within indoor heat pump cabinet.]
f.
Hose Kits: Kits shall include two 0.6 m 2 foot long metal braided
hoses with swivel connectors on one end, [an flow control valve
with test ports,] two shutoff ball valves with memory stops (one
with test port), blow down ball valve, and Y-strainer. Hoses
shall be fire rated to meet UL 94. Hoses shall have a maximum
working pressure of 2067 kPa 300 psi.
g.
Hanger Kits: Provide units with hanger kits consisting of
galvanized steel brackets, bolts, washers, and vibration
isolators. The hanger kit shall be designed to support the unit
from below and suspend from threaded rods.
**************************************************************************
Note: Microprocessor based controls should normally
be utilized on large projects. Electromechanical
controls should be used on small installations,
housing, and remote location projects.
**************************************************************************
h.
Controls: Controls and safety devices shall be factory wired and
mounted within the control box of the unit cabinet.
(1) Provide a microprocessor based controller. The
microprocessor shall control sequencing, high and low pressure
switch monitoring, freeze protection, lockout control, night
setback, emergency shutdown, short cycle protection, random start,
LED mode and fault indicators, fault memory, input and output
diagnostics, and a communications port. Provide a
factory-installed low voltage terminal block for field control
wiring and a low voltage transformer. [Provide communications
capability for remote direct digital control (DDC).] [Provide a
hand held, remote service terminal from the heat pump manufacturer
capable of interfacing with heat pump unit microprocessor
controller to perform diagnostics, data retrieval, and calibration
functions.]
[(2) Provide 24 volt electromechanical controls supplied with a
low voltage transformer, pump relay, controls for compressor,
reversing valve coil, and lock out relay. Controls shall include
a random start relay, a night setback relay, and a compressor
cycling relay for demand load shedding, and a condensate overflow
switch. Provide a low voltage terminal block for field control
wiring.]
i.
Space Temperature Controls: Provide electronic multi-stage,
auto-changeover, adjustable thermostats with
OFF-HEAT-AUTO-COOL-EMERGENCY system switch and AUTO-ON fan switch.
SECTION 15741N
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