Carrier 50KQA Product Data page 23

Vertical ground loop — Use this system in vertical bore-
hole applications. This design is well suited for retrofit ap-
plications when space is limited or where landscaping is al-
ready complete and minimum site disruption is desired.
The vertical ground loop system contains a single loop of
pipe inserted into a hole. The hole is back-filled and grout-
ed after the pipe is inserted. The completed loop is con-
cealed below ground. The number of loops required de-
pends on ground conditions, heating and cooling require-
ments, and the depth of each hole.
Hybrid systems — In some applications, it may be bene-
ficial to incorporate a cooling tower into the ground loop
system to reduce the overall cost. A Hybrid System dis-
cards excess heat into the air and increases the cooling
performance of the ground loop.
Condensate drainage
Connect the console unit condensate drain to the building
condensate drain with a flexible, non-pressure rate plastic
hose. Be sure to avoid kinks in this hose to ensure an un-
obstructed flow of condensate from the unit to the drain.
The condensate hose's horizontal run is usually too short
to pose any drainage problems, however, make sure this
line is pitched at least 1 inch for every 10 feet of run (in the
direction of the flow.) Avoid low points and unpitched
piping since dirt collects in these areas and may cause stop-
page and overflow.
Installing a trap or drain in the field is not required unless
specified by local codes. The 50KQA, KQD units are
designated in a blow-thru configuration. The condensate
drain pan is located on the outlet side of the blower so that
the pressure in the drain pan is higher than the atmospher-
ic pressure.
Water conditioning
In some applications, maintaining proper water quality
may require higher corrosion protection for the water-to-
refrigerant heat exchanger. Water quality varies from loca-
tion to location and is unique for each job. Water charac-
teristics such as pH value, alkalinity, hardness, and specific
conductance are important when considering any WSHP
application. Water typically includes impurities and hard-
ness that must be removed. The required treatment de-
pends on the water quality as well as system type. Water
problems fall into three main categories:
1. Scale formation caused by hard water reduces the
heat transfer rate and increases the water pressure
drop through the heat exchanger. As water is heated,
minerals and salts are precipitated from a solution
and deposited on the inside surface of the pipe or
tube.
2. Corrosion is caused by absorption of gases from the
air coupled with water on exposed metal. Corrosion
is also common in salt-water areas.
3. Organic growths, such as algae, can reduce the heat
transfer rate by forming an insulating coating on the
inside tube surface. Algae can also promote corrosion
by pitting.
NOTE: In most commercial water loop applications, Aqua-
zone™ WSHP units use copper water-to-refrigerant heat
exchanger. Units can also be equipped with a Cupronickel
heat exchanger for applications where water is outside the
copper heat exchanger's standard contaminant limits.
WATER QUALITY GUIDELINES
CONDITION
7 to 9 range for copper. Cupronickel may be
pH
used in the 5 to 9 range.
Calcium and magnesium carbonate should not
Total Hardness
exceed 20 grains per gallon (350 ppm).
Iron Oxides Less than 1 ppm.
Iron Bacteria No level allowable.
Ammonia,
Ammonium Hydroxide
Corrosion* Ammonium Chloride,
Ammonium Nitrate
Ammonium Sulfate
Chlorine/Chlorides
Hydrogen Sulfide†
Use Cupronickel heat exchanger when
concentrations of calcium or sodium chloride
Brackish
are greater than 125 ppm are present.
(Seawater is approximately 25,000 ppm.)
*If the concentration of these corrosives exceeds the maximum allow-
able level, then the potential for serious corrosion problems exists.
†Sulfides in the water quickly oxidize when exposed to air, requiring that
no agitation occur as the sample is taken. Unless tested immediately
at the site, the sample will require stabilization with a few drops of one
Molar zinc acetate solution, allowing accurate sulfide determination up
to 24 hours after sampling. A low pH and high alkalinity cause system
problems, even when both values are within ranges shown. The term
pH refers to the acidity, basicity, or neutrality of the water supply. Below
7.0, the water is considered to be acidic. Above 7.0, water is consid-
ered to be basic. Neutral water contains a pH of 7.0.
NOTE: To convert ppm to grains per gallon, divide by 17. Hardness in
mg/l is equivalent to ppm.
Acoustical design
Sound power levels represent the sound that the source,
the WSHP unit, produces with no regard to attenuation be-
tween the source and the space. Acoustical design goals
are necessary to provide criteria for occupied spaces.
These goals help ensure that people can be comfortable
and communicate effectively over the background noise of
the air-conditioning system and other background noise
sources.
Acoustical design goals are desirable sound pressure lev-
els within a given conditioned space and are represented
by Noise Criteria (NC) curves. Noise Criteria (NC) curve
levels represent a peak over a full frequency spectrum. A
high value in a low frequency band has the same effect on
NC level as a lower value in a high frequency band. It is im-
portant that sound levels be balanced over the entire spec-
trum relative to the NC curve. The lower the NC criteria
curve, the more stringent the room acoustical design must
be to meet the design goals.
It is important to know how to convert the unit ratings
from sound power (Lw) to sound pressure (Lp). This con-
version depends on the specifics of the installation's acous-
tical environment. Assessing an area's acoustical design re-
quires that you compare the sound pressure (Lp) with the
NC curve for the selected area.
ACCEPTABLE LEVEL
Max Allowable Coaxial
Level Metal
0.5 ppm
0.5 ppm
0.5 ppm
0.5 ppm CuNi
None Allowable
Cu
Cu
Cu
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