CLIMATEMASTER WATER-SOURCE HEAT PUMPS
20 ClimateMaster Water-Source Heat Pumps
Tranquility 16 (TC) Series
Rev.: 25 July, 2017
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 flushing of the heat exchanger. Shut off
valves should be positioned to allow flow through the
coax via the boiler drains without allowing flow into
the piping system. P/T plugs should be used so that
pressure drop and temperature can be measured.
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 field, 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).
Flow Regulation
Flow regulation can be accomplished by two methods.
One method of flow regulation involves simply
adjusting the ball valve or water control valve on the
discharge line. Measure the pressure drop through
the unit heat exchanger, and determine flow rate from
Tables 8a through 8e. Since the pressure is constantly
varying, two pressure gauges may be needed. Adjust
the valve until the desired flow of 2.0 to 2.6 l/m per kW
is achieved. A second method of flow control requires a
flow control device mounted on the outlet of the water
control valve. The device is typically a brass fitting with
an orifice of rubber or plastic material that is designed
to allow a specified flow rate. On occasion, flow
control devices may produce velocity noise that can be
reduced by applying some back pressure from the ball
valve located on the discharge line. Slightly closing the
valve will spread the pressure drop over both devices,
lessening the velocity noise.
NOTE: When EWT is
below 10°C, 2.6 l/m per kW is 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 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 qualified 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 flushing. In some cases,
the desuperheater option should not be recommended
due to hard water conditions and additional
maintenance required.
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, 66°C for direct use (well water/open
loop) and DHW (desuperheater); 32°C for indirect use.