Architect and Engineering Manual

49
Heat pump unit shall include reverse cycle defrost that
automatically begins a defrost cycle when hardware and
software determines the criteria for defrosting has been
met. Defrosting shall be accomplished by systematically
ceasing heat pump operation, pausing to allow internal
refrigerant pressures to equalize, and then operating the
compressor with the flow of refrigerant reversed to allow
the hot gas to flow through the outdoor coil, melting the
accumulated frost. The unit shall automatically resume
heat pump operation, after pausing to allow refrigerant
pressures to equalize, at conclusion of defrost cycle.
The unit shall be equipped with a temperature-activated
drain valve to allow water generated in heat pump
operation and defrost cycles to drain into the wall sleeve.
The unit shall have a switch concealed from room occupant
to allow heat pump operation to be overridden and heat
provided by electric resistance heat regardless of
outdoor temperature.
In the event of compressor failure during heat pump
operation, unit shall automatically switch to electric
resistance heat to maintain selected room temperature
regardless of outdoor temperatures.
Specifications for optional Internal Condensate
Removal (ICR) system for AZ65 Series heat pump units.
The unit shall have a factory-installed Internal Condensate
Removal (ICR) system to permit unit to automatically
dispose of heat-pump-generated condensate water with
no overflow to outdoors during heating under outdoor
ambient of 55°F dry bulb, 90% relative humidity; indoor
ambient 70°F dry bulb, 52% relative humidity, for four
hours of continuous run time.
WALL SLEEVES AND GRILLES
(NEEDED FOR NEW INSTALLATIONS.)
(Alternate specification for steel wall sleeve)
Wall Sleeve. The wall sleeve shall be constructed of heavy-
gauge, insulated, zinc-coated phosphated steel with a
protective baked-on enamel finish. Bottom critical points
of the steel wall sleeve shall be coated with petroleum
microcrystalline wax for added corrosion protection and
shall meet ASTM B-117, 1,800-hour hot air aerated salt
spray test.
(Alternate specification for molded wall sleeve)
Wall Sleeve. The wall sleeve shall be constructed of a
non-corroding fiberglass-reinforced polyester compound.
Sleeves shall be installed through exterior walls where
shown on the plans and shall be installed per
manufacturer’s installation instructions. In no instance shall
fasteners be used through the bottom in order to retain the
water integrity of the bottom of the wall sleeve.
Outside weather panels shipped with the sleeves shall
remain in place until the outdoor grille and chassis are
installed, at which time they are to be removed and
discarded by the installer.
Outside Grille. Each unit shall be equipped with a standard
exterior grille that has been designed to allow unit
operation in high ambient conditions. Grilles shall be of
material and design specified.
Special grilles or customer louver sections to be supplied
by others will conform to a minimum of 65% free area (as
calculated by Ashrae) to allow for proper unit operation
and shall be submitted to the PTAC/PTHP manufacturer,
if requested, for feasibility and airflow characteristics.
SPECIFICATIONS FOR SUB-BASE (IF REQUIRED)
Sub-Base. Each unit shall have a field-installed UL-listed
electrical sub-base. The sub-base shall be attached to the
lower inside flange of the wall sleeve prior to installation in
the exterior wall. It shall include adjustable screws at the
bottom corners to permit exact leveling of the wall sleeve.
The sub-base shall have a factory-installed receptacle to
allow unit line cord to plug into mating receptacle and shall
have a chaseway to contain and conceal the line cord. The
sub-base shall have side panels adjustable from a minimum
of 2-3/8" to a maximum of 13-3/4" to enclose the area
under the wall sleeve.
Weather Resistance. Complete unit including outside
louver shall be submitted to an independent agency for
weather-resistance tests.
Air-infiltration test to be conducted in accordance with
AHRI 310/380 and in such a facility for leakage air flow
measurements described in ANSI/ASHRAE 16 and 58. With
indoor static pressure maintained at 0.1" in H
2
O below the
outdoor static pressure, the allowable air infiltration shall
not exceed 19.3 ft.
3
/min.
Water-infiltration test to be conducted in accordance
with ASTM E331-86 with static air pressure differential
of 10.0 lb./ft
2
(1.93" H
2
0) equivalent to 63 mph wind,
5.0 gal./ft
2
(8" rain/ft
2
/hr.) for 15 minutes and there
shall be no leakage into the room.
Approvals. Units shall be certified under the AHRI and cUL
certification program and listed by UL.
Service. Submit complete information with bid covering
service availability to whom service on units will be
assigned, along with complete address and phone number,
including phone number of emergency service personnel.
Start-Up, Adjust, Demonstrate. Contractor shall be
responsible for the initial starting of units, adjustments
thereto, etc., to place the units in required operating
condition. Contractor shall demonstrate to the owner or his
representative the operation of units for both summer and
winter functions.
Warranty. The warranty shall be a full one-year parts
and labor on the entire unit, plus an additional full four
years parts and labor for the sealed refrigerating system,
including service call for diagnosis and transportation to
and from service shop (if necessary) at no charge to the
customer. The warranty shall also include a limited second-
through- fifth-year parts-only warranty for fan motors,
switches, heater, heater protectors, compressor overload,
solenoids, circuit boards, auxiliary controls, thermistors,
frost controls, ICR pump, capacitors, varistors and indoor
blower bearing.
Installation Responsibility. Units shall be installed
according to the manufacturer’s recommendations and
the manufacturer shall not be responsible for unit failure
as a result of improper installation, or unit performance
when installed with accessories not approved by
the manufacturer.
SUGGESTED BID FORM SPECIFICATIONS (CONTINUED)