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6. When all units on a riser are anchored into place, com-
plete riser joints as follows:
a. Verify that all riser joints are vertically aligned and
that risers penetrate at least 1 in. into the swaged
joint of the riser below. DO NOT let riser joint bot-
tom out.
b. Braze riser joints with a high-temperature alloy
using proper Phos-copper of Silfos. Soft solder 50-
50, 60-40, 85-15, or 95-5 or low temperature alloys
are not suitable riser weld materials.
c. Anchor built-in risers to the building structure with
at least one contact point. To accommodate vertical
expansion and contraction DO NOT fasten risers
rigidly within the unit.
d. Verify that unit shut-off valves are closed. DO
NOT OPEN VALVES until the system has been
cleaned and flushed.
e. Flush system; refer to System Cleaning and Flush-
ing section for more information.
f. Install vents in piping loop as required to bleed the
system of air accumulated during installation.
7. Install supply duct extension(s) provided with the cabinet
by folding the tabs down to secure extension(s) to
cabinet.
COMMERCIAL WATER LOOP APPLICATION — Com-
mercial systems typically include a number of units connected
to a common piping system. Any unit plumbing maintenance
work can introduce air into the piping system; therefore, air
elimination equipment is a major portion of the mechanical
room plumbing. In piping systems expected to utilize water
temperatures below 50 F,
1
/
2
in. closed-cell insulation is re-
quired on all piping surfaces to eliminate condensation. Metal
to plastic threaded joints should never be used due to their ten-
dency to leak over time.
Teflon tape thread sealant is recommended for use in system
piping to minimize internal fouling of the heat exchanger. Do
not over tighten connections and route piping so as not to inter-
fere with service or maintenance access. Hose kits include shut
off valves, pressure/temperature (P/T) plugs for performance
measurement, high pressure stainless steel braided hose, and
hose adaptors.
Balancing valves and variable speed pumping systems my
also be used.
The piping system should be flushed to remove dirt, pipe
shavings, chips, and other foreign material prior to operation.
See System Cleaning and Flushing section. The flow rate is
usually set between 2.25 and 3.5 gpm per ton for most
applications of water loop heat pumps. To ensure proper main-
tenance and servicing, P/T ports are imperative for temperature
and flow verification, as well as performance checks.
Water loop heat pump (cooling tower/boiler) systems typi-
cally utilize a common loop, maintained between 60 to 90 F.
The use of a closed circuit evaporate cooling tower with a sec-
ondary heat exchanger between the tower and the water loop is
recommended. If an open type cooling tower is used continu-
ously, chemical treatment and filtering will be necessary.
GROUND-LOOP HEAT PUMP APPLICATION
NOTE: In most commercial building applications using a
frame style or plate style heat-exchanger should be used to iso-
late the water source heat pump units from the ground water
loop increasing system performance, equipment longevity.
Pre-Installation
— Prior to installation, locate and mark all ex-
isting underground utilities, piping, etc. Install loops for new
construction before sidewalks, patios, driveways, and other
construction has begun. During construction, accurately mark
all ground loop piping on the plot plan as an aid in avoiding po-
tential future damage to the installation.
Piping Installation
— All earth loop piping materials should
be limited to polyethylene fusion only for in ground sections of
the loop. Galvanized or steel fittings should not be used at any
time due to their tendency to corrode. All plastic to metal
threaded fittings should be avoided due to their potential to leak
in earth coupled applications. A flanged fitting should be sub-
stituted. P/T plugs should be used so that flow can be measured
using the pressure drop of the unit heat exchanger.
Earth loop temperatures can range between 25 and 110 F.
Flow rates between 2.25 and 3.0 gpm per ton of cooling capac-
ity is recommended in these applications.
Test individual horizontal loop circuits before backfilling.
Test vertical U-bends and pond loop assemblies prior to
installation.
Pressures of at least 100 psi should be used when testing.
Do not exceed the pipe pressure rating. Test entire system
when all loops are assembled.
Flushing the Earth Loop
— Upon completion of system in-
stallation and testing, flush the system to remove all foreign ob-
jects and purge to remove all air.
Antifreeze
— In areas when minimum entering loop tempera-
tures drop below 40 F or where piping will be routed through
areas subject to freezing, antifreeze is required. Alcohols and
glycols are commonly used as antifreeze; however your local
Carrier distributor should be consulted for the antifreeze best
suited to your area. Freeze protection should be maintained to
15 F below the lowest expected entering loop temperature. For
example, if 30 F is the minimum expected entering loop tem-
perature, the leaving loop temperature would be 25 to 22 F and
freeze protection should be at 15 F. Calculation as follows:
30 F 15 F = 15 F.
All alcohols should be premixed and pumped from a reser-
voir outside of the building when possible or introduced under
the water level to prevent fumes. Calculate the total volume of
fluid in the piping system. Then use the percentage by volume
shown in Table 2 for the amount of antifreeze needed. Anti-
freeze concentration should be checked from a well mixed
sample using a hydrometer to measure specific gravity.
Table 2 — Antifreeze Percentages by Volume
*Must not be denatured with any petroleum based product.
OPEN - LOOP GROUND WATER SYSTEMS — Shut off
valves should be included for ease of servicing. Boiler drains or
other valves should be “tee’d” into the lines to allow acid flush-
ing of the heat exchanger. P/T plugs should be used so that
pressure drop and temperature can be measured. Piping materi-
als should be limited to copper or PVC SCH80.
NOTE: Due to the pressure and temperature extremes, PVC
SCH40 is not recommended.
Water quantity should be plentiful and of good quality. Con-
sult Table 3 for water quality guidelines and recommendations.
Copper is recommended for closed loop systems and open loop
ground water systems that are not high in mineral content or
corrosiveness. In ground water situations where scaling could
be heavy or where biological growth such as iron bacteria will
be present, an open loop system is not recommended. Heat ex-
changer coils may over time lose heat exchange capabilities
due to build up of mineral deposits. Heat exchangers must only
be serviced by a qualified technician, as acid cleaning agents
and special pumping equipment are required.
TYPE
MINIMUM TEMPERATURE FOR LOW
TEMPERATURE PROTECTION
10 F 15 F 20 F 25 F
Methanol 25% 21% 16% 10%
100% USP Food Grade
Propylene Glycol
38% 25% 22% 15%
Ethanol* 29% 25% 20% 14%
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