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Heat Controller, Inc. HTV/HTD/HTH SERIES Engineering Design Guide
2
Two Stage Geothermal Heat Pump Systems
Features of the Two Stage HT Series
The HT Series Geothermal Heat Pumps are some of the most efcient and innovative geothermal units on the market today.
Packed with features, they offer the best value to the homeowner who is interested in quiet comfort and low operating costs
as a result of extraordinary efciencies.
Technically, the HT Series are state-of-the-art with digital electronic controls, multi-stage scroll compressors, computer
controlled fan motors, zero ozone depleting refrigerant, and much more.
Design Features
• Five capacities to meet all application requirements—two,
three, four and six ton models.
• Efcient operation from 20°F to 120°F entering water tempera-
tures. Flow rates may be as low as 1.6 gpm/ton.
• Top supply air discharge accommodates upow applications.
• Select left or right hand return air positions for all models;
cabinets include a deluxe lter rack/duct collar.
• Variable speed ECM blower motor adjusts to multiple duct
system applications and provides soft start for added comfort
and quiet operation.
• Narrow cabinet design can be easily moved through doorways.
• Internally trapped condensate piping (on all vertical units)
allows easy, compact installation.
• Internal electric heat unit (optional) is designed for easy eld
installation.
• Electric box is positioned for easy eld wiring from two sides.
• Loop pump power block is built with circuit breaker.
• Coaxial low temperature protection can be selected in the eld
for well or closed loop installations.
• Air coil low temp. protection utilizes high accuracy thermistors.
• Coaxial heat exchanger, refrigerant suction lines, hot water
generator coil, and all water pipes are fully insulated to reduce
condensation in low temperature conditions.
• Isolation mounted compressors and low RPM blowers are used
to reduce noise; compressor compartment and interior cabinet
are insulated with 1/2" coated glass ber insulation.
• Double isolated compressor delivers extra quiet operation.
• Safety features include: high pressure and loss of charge pro-
tection for the compressor; condensate overow protection; low
temperature protection sensors to safeguard the coaxial heat
exchanger and air coil; hot water high-limit hot water genera-
tor pump shutdown; fault lockout that enables emergency heat
and prevents compressor operation until thermostat or circuit
breaker has been reset.
Operating Efciencies
• AHRI/ASHRAE/ISO 13256-1 ratings for heating COPs and
cooling EERs are industry leaders.
• Hot water generator (HWG) with internal pump generates hot
water at dramatic savings while improving system performance.
• Efcient scroll compressors provide quiet, reliable operation.
• Oversized coaxial tube water-to-refrigerant heat exchanger
delivers high efciency and extra heating capacity; convoluted
water tube functions efciently at low ow rates and provides
resistance to freeze damage.
• Oversized ried copper tube/lanced aluminum n air-to-refriger-
ant heat exchanger offers high efciencies at low air velocity.
• Large, low RPM blower is both quiet and efcient, and provides
high static capability.
Service Advantages
• Three removable access panels for the compressor compartment
and one or two (depends on model) for the air handler compart-
ment offer quick access to all internal components even with
ductwork in place, making the unit service-friendly.
• Built with bi-directional thermal expansion valve.
• Brass, swivel water connections make it easy to connect loop
and hot water piping.
• Insulated divider and separate air handling/compressor access
panels allow service testing without air bypass.
• Design allows in-place service in tight installation spaces.
• CXM control features LED status light with memory feature for
easy diagnostics.
• Control box and fan motors have quick-attach wiring connections
for fast removal/reconnection.
• Biow liquid line lter drier is factory-installed.
• 75 VA control transformer comes with circuit breaker.
• Internal drop-out blower assemblymakes servicing simple.
• Refrigerant circuit includes high and low pressure service ports.
• E-coated refrigerant-to-air coil helps protect the coil from
corrosion and extends life expectancy.
Factory Quality
• All units are built using our state-of-the-art manufacturing system
that is designed to assure quality of the highest standards. This
system:
-Veries that the correct components are being assembled;
-Automatically performs special leak tests on all joints;
-Conducts pressure tests;
-Performs a highly detailed run test;
-Automatically prevents a "failed" unit from being packaged for
shipment;
-Creates a computer database of run tests for future service
analysis and diagnostics;
-Includes painting heavy gauge steel cabinets with durable epoxy
for a long-lasting nish;
-Performs all refrigerant brazing in a nitrogen-rich environment;
-Evacuates units to a deep vacuum of less than 50 microns
prior to refrigerant charging
-Halogen leak tests all joints to ensure a leak rate of less
than 1/4 ounce per year.
Options & Accessories
• Optional internal auxiliary electric heat.
• Electronic auto-changeover thermostats with indicator LEDs.
• Closed loop ow controller and hose kits.
See Geo Accessories brochure for complete list of accessories.