12
RW SERIES REVERSIBLE CHILLER INSTALLATION MANUAL
RW Series Application Data
1.0. Minimum Fluid Volume
A. Water-to-water heat pumps require a minimum amount of load
side fl uid volume to ensure accurate and stable temperatures
during system operation. For normal air conditioning type
applications, it is recommended to use at least 7 gallons/ton.
B. Applications that require more precise temperature control or
low loading will occur the minimum fl uid volume shall be no
less than 10 gallons/ton. Installation of a buffer tank that will
properly mix the fl uid is recommended.
1.1. Water-to-Water Heat Pump Sizing
A. Heat pumps should be adequately sized for optimal
system effi ciency and run time. Oversizing by more than
15% can diminish performance resulting in higher power
consumption, short cycling of compressors, and unstable
conditioning temperatures.
B. In applications where the minimum load is signifi cantly less
than the design condition, it is better to install 2 smaller heat
pumps for load matching rather than a single large heat pump.
1.2. Heat Pump Piping
A. Multiple heat pumps can be installed in series or parallel
confi gurations. The preferred system design is to pipe the
equipment in parallel due to its simplicity and fl exibility. In
parallel systems, the heat pump equipment can vary in size
as long as fl ow rate and system volume are accounted for.
B. Piping equipment in series is not desired; however, it can
be done if proper guidelines are followed. Always observe
proper temperature and fl ow rate requirements for each
unit. Sometimes this method is desired to achieve larger
temperature differences.
1.3. Strainers
A. All brazed-plate heat exchangers shall have a strainer within
8 ft of the water/brine inlet. It is highly recommended to use a
minimum of 60 mesh in order to provide maximum fi ltration.
In any case, the strainers should never have a mesh size less
than 20.
B. Failure to install proper stainers and perform regular service
can result in serious damage to the unit, and cause degraded
performance, reduced operating life and failed compressors.
Improper installation of the unit (which includes not having
proper strainers to protect the heat exchangers) can also
result in voiding the warranty.
C. Strainers should be selected on the basis of acceptable
pressure drop, and not on pipe diameter. The strainers
selected should have a pressure drop at the nominal fl ow rate
of the units; low enough to be within the pumping capacity of
the pump being used.
1.4. Flow Sensing Devices
A. A
fl ow switch or equivalent must be installed on the
evaporator for each unit to be installed. If the unit is to operate
as both modes (heating/cooling), a fl ow switch is needed on
both heat exchangers.
B. A differential pressure switch can be used in place of a fl ow
switch. The differential switch must be capable of pressure
range as indicated in the pressure drop tables.
1.5. Water Quality
A.
General:
Reversible chiller systems may be successfully
applied in a wide range of commercial and industrial
applications. It is the responsibility of the system designer
and installing contractor to ensure that acceptable water
quality is present and that all applicable codes have been
met in these installations.
B.
Water Treatment:
Do not use untreated or improperly treated
water. Equipment damage may occur. The use of improperly
treated or untreated water in this equipment may result in
scaling, erosion, corrosion, algae or slime. The services of
a qualifi ed water treatment specialist should be engaged to
determine what treatment, if any, is required. The product
warranty specifi cally excludes liability for corrosion, erosion or
deterioration of equipment.
The heat exchangers in the units are 316 stainless steel plates
with copper brazing. The water piping in the heat exchanger
is steel. There may be other materials in the building’s piping
system that the designer may need to take into consideration
when deciding the parameters of the water quality.
If an antifreeze or water treatment solution is to be used, the
designer should confi rm it does not have a detrimental effect
on the materials in the system.
C.
Contaminated Water:
In applications where the water quality
cannot be held to prescribed limits, the use of a secondary or
intermediate heat exchanger is recommended to separate the
unit from the contaminated water.
The following table outlines the water quality guidelines for
unit heat exchangers. If these conditions are exceeded, a
secondary heat exchanger is required. Failure to supply a
secondary heat exchanger where needed will result in a
warranty exclusion for primary heat exchanger corrosion
or failure.
WARNING: Must have intermediate heat exchanger
when used in pool applications.
