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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
®
2 0 ( T S ) S e r i e s
R e v. : 0 6 / 1 7 / 1 5
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 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.
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 CPVC 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 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 19). Note the special wiring diagrams for slow
closing valves (Figures 20 & 21).
