Carrier WEATHERMASTER 38HQ - Manual (Page 2)

It’s like having two heat pumps in one!
Carrier engineers have developed the most skillfully designed and
unique heat pump systems since the first heat pump was built by
Carrier back in 1932 The 38HQ is far more than a conventional
heat pump it’s more like having two extra-efficient heat pumps
in one And there’s no other like it
The 38HQ joins the quality-proven family of Weathermaster III
heat pump systems The added feature of a second compressor
provides extra operating efficiency for heating at lower outdoor
temperatures
The energy-saving principle of reverse cycle
heating and cooling
Like other Carrier heat pumps, the 38HQ is an electrically
operated system that provides comfortable temperatures for your
home all year long When heating, the system absorbs heat from
cold outside air (even sub-zero outdoor air contains usable heat)
and brings it inside to heat your home
Unlike other residential heat pumps, the 38HQ has a two-
compressor capability that makes it ideal for areas prone to
extreme, prolonged winter cold By establishing a second thermal
balance point for the system (see right), more heat at lower
energy cost is made available than would be in a conventional one-
compressor system Since over half of North America experiences
7000 or more heating degree days per year, the dual-compressor
system makes good heating sense. The extra capacity of the
38HQ provides higher heating output at lower annual energy cost
Even in more temperate regions, the dual-compressor system
offers dependable, efficient operation Here’s how it works
If the outdoor temperature drops to a level at which the first
compressor can no longer deliver enough heat (the first thermal
balance point), the second compressor automatically energizes to
boost system capacity to provide more heat with high efficiency
Once the system reaches its second thermal balance point, aux­
iliary electric heaters can provide enough heat for indoor comfort
even on the most frigid winter nights
When cooling, the 38HQ system reverses the heating cycle by
removing heat from indoors and rejecting it outdoors The cooling
cycle uses one of the compressors, the one sized to meet the total
cooling load
Any single-compressor heat pump teaches a theimal balance point where
insufficient heat can be extracted from outdoors (A) The piesence of the
second compressoi in the dual compressor 38HQ system extends high-
efficiency heat pump heating operation to a second, lower thermal balance
point (B) to piovide significant dollar savings
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Three reasons to buy the Weathermaster III
Dual Compressor
Heat Pump
The 38HQ dual-compressor heat pump system is available in two sizes with
capacities of 29,000 and 34,500 Btuh cooling, 42,000 and 48,000 Btuh heating
The system consists of three separate components — indoor fan-coil, outdoor
coil, and compressor section — to afford maximum flexibility, accessibility
and easy maintenance
1. Compressor Section
Two compressors fit compactly into one con­
venient enclosure that can be installed in your
garage, utility room, breezeway or basement
This allows the compressors to be sheltered, away
from bad weather, yet remain easily accessible for
servicing This easy accessibility can translate
directly into dollars saved on labor costs
Compressor muffler and special acoustical
treatment reduce operating sound All connec­
tions are on top of the enclosure to speed installa­
tion. Top cover and front panel are removable for
ready access to compressors, reversing value,
control system, and related components. The
second compressor is preset by the installer to
activate automatically when needed, assuring
dependable operation at lowest cost for your
particular area
2. Outdoor Section
This distinctively styled unit is Cairier’s popular
Round One Only the king-size circular coil,
outdoor fan and motor, and control box are con
tained in this enclosure Because of its light
weight, this section can easily be mounted on a
wall instead of on the ground, protecting it from
pets and growing shrubbery Wall-mounting is
also beneficial in heavy snowfall regions
3. Indoor Section
No special indoor coil is needed for the 38HQ
dual-compressor system Select the indoor sec
tion from a variety of approved Can ier heat pump
system coils and fan sections
A combination of the 28HQ horizontal or 28VQ
vertical coil plus the 40FS modular fan section
provides a simply installed, easy to maintain
indoor section for upflow, downflow or horizontal
applications
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