3
Plumbing
It is preferable that the heat pump is connected to filtered water.
It is essential that the water recirculating pump and pipe sizes be engineered to suit the particular
application, giving correct water flow through the heat pump as per the specification requirements
of the unit. Inadequate or excessive water flow detracts from heating efficiency and can lead to
damage to the unit. Selection of the recirculating pump must be made in accordance with the
design flow rate and pressure as per the pump
manufacturer’s specification.
If unsure, contact Rheem Thermal for recommendations on the optimum flow rate. Assistance
will be provided where possible in relation to plumbing design and pump selection.
Water connections on the unit are clearly marked as water inlet and water outlet.
The installation of breakable unions on both inlet and outlet pipes will facilitate maintenance and
water drainage of the system. If the unit is situated below the pool level or an open holding tank,
shut off valves should be fitted on the water side of both unions so that removal of the machine
is possible without draining the system.
A separate circuit is generally the most desirable plumbing configuration with individual flow and
return line and filter strainer. This may not always be possible particularly with established pools.
Heat pumps may be plumbed in-line with existing filter equipment, although thought must be
given to correct flow, run time and possible over chlorinating and/or dosing by extended running
of automatic chlorinator, feeders, etc. Typical plumbing schematics for installation with existing
filtration and with a dedicated heating circuit are shown in Section 6.
A one-way check valve should be installed on the outlet of the heat pump.
Models without an internal water flow by-pass must have an external by-pass fitted.
Where multiple units are installed, the heaters must be installed in parallel to equalise pressure
drops and balance flow through the heaters. Systems of two or more Heat Pumps require a
manifold.
All Plumbing should be carried out by qualified tradesman (plumber).
Chemical Treatment
Rheem Thermal heat pumps designed for swimming pool or spa heating will include a titanium heat
exchanger. This material is impervious to chemical corrosion and as such, variations in water quality
will not cause damage to the titanium tube. However, it is recommended as a matter of good pool
management that the correct chemical balance of the water be maintained as follows:
pH to be kept between 7.2 and 7.8
Alkalinity must not exceed 200 PPM
Free available chlorine must not exceed 6.0 PPM
Chemicals must be added downstream side of the Heat Pump.
In line chlorinator must be installed downstream of the Heat Pump.
The maintenance of the above guidelines does not in itself ensure that water is in balance and non-
corrosive. Various mechanisms are available to monitor water conditions and information on the
Langlier Saturation Index is provided as a commonly applied industry standard.
