Specifications

26
Roth RXT Series Catalog - August 2010
Engineering Specications
General
The Geothermal Heat Pump system and the earth loop shall be
one system and include all interconnecting piping and controls
to provide an ecient, harmoniously balanced package. All
units shall be tested and rated by ETL in accordance with UL
and CSA test laboratory safety and performance standards.
Each unit shall be computer run-tested at the factory. Capacities
and eciencies shall be certied by AHRI and meet CSA
standards. Each unit shall be mounted on a pallet and shipped
in a corrugated box. Units shall be designed to operate with
entering liquid temperature between 25°F and 110°F.
Refrigerant Circuit
Compressor shall be hermetically sealed high ecient two-
stage scroll, quadruple-isolated. The air heat exchanger
(coated) coil shall use high-density technology, low-face velocity
and incorporate enhanced aluminum ns bonded to copper
tubing not less than three rows deep, and be e-coated for
corrosion protection. The coaxial water heat exchanger shall
be designed for low water pressure drop and constructed of
a an optional cupro-nickel or standard copper inner tube and
a steel outer tube with enhanced heat exchanger surface.
Water heat exchanger shall be encapsulated in an air-tight
foamed enclosure to prevent condensation at low temperature
operation. An optional domestic water desuperheater coil
of vented double wall copper construction for potable water
with high limit control shall be employed. The thermostatic
expansion device shall be bi-directional, mechanical controlled
and shall provide proper superheat over the entire liquid
temperature range with minimal hunting. The reversing valve
shall be of copper construction with a 24V AC solenoid valve
with fail-to-heating position.
Cabinet
The cabinet shall be of heavy gauge steel with powder coat
nish (front access panels shall be brushed stainless steel).
It shall incorporate a stainless steel condensate pan and be
installed with high-density insulation, with smoke and ame
spread of class 1 type and acoustic value of NRC 45. It shall be
oriented to allow complete component service access from all
sides. Electrical box shall be of heavy gauge steel located on
the top of the cabinet for eye-level access. A duct collar shall be
provided for the supply air opening (eld-installed) and a return
air lter, rack & duct collar shall be provided on the return air
opening. Standard size 1-inch lters shall be provided with each.
Controls and Blower Motor
Units shall incorporate a microprocessor based control board.
All equipment shall incorporate both high and low pressure
switches and freeze protection (via ow switch) with total
refrigerant circuit lockout with manual reset. The board shall
provide a terminal block, LED status, fault indicators, fault
memory and accessory output. All units shall have knockouts
for entrance of line & low voltage wiring.
Fan Motor & Assembly
The fan shall be a direct driven type. The motor shall be a
variable-speed ECM motor with direct drive blower that can be
easily removed from the heat pump without duct disconnection.
The ECM fan motor shall be soft starting and maintain constant
CFM over its operating static pressure range. The fan motor
shall be isolated from the housing by rubber grommets. The
ECM motors shall be long life ball bearing type.
Piping & Connections
Loop water connections (supply/return) shall be 1-inch FPT
ttings, which provide a union for easy connection. All water
piping shall be insulated to prevent condensation at low water
temperatures. The condensation connection shall be ¾“ female
threaded connection.
Note: Copper is the only acceptable material for piping
the desuperheater.
Secondary Drain Pan
A secondary drain pan should be eld furnished and installed
under the unit, on horizontal unit or any other unit that is
mounted overhead in an attic or second oor, or where required
by local code.