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c l i m a t e m a s t e r. c o m
T H E S M A R T S O L U T I O N F O R E N E R G Y E F F I C I E N C Y
Tr a n q u i l i t y
®
3 0 ( T T ) S e r i e s
R e v. : 0 7 / 1 8 / 1 3
Ground-Water Heat Pump Applications
Open Loop - Ground Water Systems
- Typical open
loop piping is shown in Figure 14. 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 fl ushing of
the heat exchanger. Shut off valves should be positioned
to allow fl ow through the coax via the boiler drains without
allowing fl ow into the piping system. P/T plugs should
be used so that pressure drop and temperature can be
measured. Supply and return water piping materials should
be limited to copper, PE, or similar material. PVC or CPVC
should never be used as they are incompatible with the
POE oils used in HFC-410A products and piping system
failure and property damage may result.
Water Quality Standards
- Table 3 should be consulted
for water quality requirements. Scaling potential should
be assessed using the pH/Calcium hardness method.
If the pH <7.5 and the calcium hardness is less than
100 ppm, scaling potential is low. If this method yields
numbers out of range of those listed, the Ryznar Stability
and Langelier Saturation indecies should be calculated.
Use the appropriate scaling surface temperature for the
application, 150°F [66°C] for direct use (well water/open
loop) and DHW (desuperheater); 90°F [32°F] for indirect
use. A monitoring plan should be implemented in these
probable scaling situations. Other water quality issues
such as iron fouling, corrosion prevention and erosion and
clogging should be referenced in Table 3.
Expansion Tank and Pump
- Use a closed, bladder-
type expansion tank to minimize mineral formation due
to air exposure. The expansion tank should be sized to
provide at least one minute continuous run time of the
pump using its drawdown capacity rating to prevent
pump short cycling. Discharge water from the unit is not
contaminated in any manner and can be disposed of in
various ways, depending on local building codes (e.g.
recharge well, storm sewer, drain fi eld, adjacent stream
or pond, etc.). Most local codes forbid the use of sanitary
sewer for disposal. Consult your local building and zoning
department to assure compliance in your area.
Water Control Valve
- Note the placement of the water
control valve in Figure 14. Always maintain water pressure
in the heat exchanger by placing the water control valve(s)
on the discharge line to prevent mineral precipitation
during the off-cycle. Pilot operated slow closing valves are
recommended to reduce water hammer. If water hammer
persists, a mini-expansion tank can be mounted on the
piping to help absorb the excess hammer shock. Ensure
that the total ‘VA’ draw of the valve can be supplied by
the unit transformer. For instance, a slow closing valve
can draw up to 35VA. This can overload smaller 40 or
50 VA transformers depending on the other controls in
the circuit. A typical pilot operated solenoid valve draws
approximately 15VA (see Figure 21). Note the special
wiring diagrams for slow closing valves (Figures 22 & 23).
Open Loop - Ground Water Systems
Ground Water Heat Pump App
Ground Water Heat Pump App
WARNING!
Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes
in contact with PVC or CPVS piping, may cause failure of
the PVC/CPVC. PVC/CPVC piping should never be used
as supply or return water piping with water source heat
pump products containing HFC-410A as system failures and
property damage may result.
WARNING!
Water quantity should be plentiful and of good quality.
Consult table 3 for water quality guidelines. The unit can
be ordered with either a copper or cupro-nickel water
heat exchanger. Consult Table 3 for recommendations.
Copper is recommended for closed loop systems and open
loop ground water systems that are not high in mineral
content or corrosiveness. In conditions anticipating heavy
scale formation or in brackish water, a cupro-nickel heat
exchanger is recommended. 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 exchanger coils may over time
lose heat exchange capabilities due to build up of mineral
deposits. Heat exchangers must only be serviced by a
qualifi ed technician, as acid and special pumping equipment
is required. Desuperheater coils can likewise become scaled
and possibly plugged. In areas with extremely hard water,
the owner should be informed that the heat exchanger
may require occasional acid fl ushing. In some cases, the
desuperheater option should not be recommended due to
hard water conditions and additional maintenance required.
