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NOTE: High chemical concentration from feeders and
chlorinators that are out of adjustment will cause very
rapid corrosion to the heat exchanger in the heaters.
Such damage is not covered under the warranty.
UNITHERM GOVERNOR OPERATION
(PREMIUM BRONZE HEADERS ONLY)
The patented Unitherm Governor is a thermostatic
mixing valve specifically designed to maintain constant
heater internal temperature between 105° - 115°F despite
continually changing flow rates from the filter and chang-
ing pool temperatures. This narrow range is needed to
prevent damaging condensation on the burners which will
occur if the heater runs for any length of time below 100°F.
It is also needed to inhibit scale formation in the tubes by
maintaining temperatures well below accelerated scaling
temperatures.
INTERNAL AUTOMATIC BY-PASS VALVE
A built-in automatic by-pass valve is provided in the
in/out header. The internal by-pass valve automatically
responds to changes in water pressure in the piping
system. Proper amount of water flow is maintained
through the heater under varying pressures dictated by
the conditions of the pump and filter.
EXTERNAL AUXILIARY BYPASS VALVE
(Where required)
An auxiliary bypass valve should be used when flow
rates exceed 115 GPM (usually a high performance
pump size larger than 2 HP will exceed this flow rate).
This valve is required to complement the function of the
automatic bypass valve, particularly when starting the
heater in winter or early spring when the spa or pool
temperature is down below 55°F. It also serves to
eliminate needless pressure drop through the heater and
accompanying reduction in the flow rate to the spa jets,
etcetera.
From Heater
To Pool
Auxiliary Bypass Valve (do not use gate valve)
Fig. # 8078.0
To Heater
Fig. # 8150.
From Pool
AUXILIARY BYPASS VALVE ADJUSTMENT
To set bypass: With clean filter, adjustment is made
by feeling the inlet and outlet pipes at the heater. Outlet
pipes should be slightly warmer than inlet and comfort-
able to the touch. If pipe is hot, close bypass; if cold, open
bypass.
PRESSURE RELIEF VALVE INSTALLATION
To conform to local building codes, it may be neces-
sary to install a pressure relief valve. A 3/4" pressure relief
valve having a capacity equal to BTU/HR output of the
model to be installed is recommended for this appliance.
A 3/4" NPT connection is provided in the inlet/outlet
header for installation of a pressure relief valve. The valve
shall be installed in a vertical position.
PRESSURE RELIEF
VALVE
INLET/OUTLET HEADER
NOTE: To avoid water damage or scalding due to valve
operation, drain pipe must be connected to valve outlet
and run to a safe place of discharge. Drain pipe must be
the same size as the valve discharge connection
throughout its entire length and must pitch downward
from the valve. No shut-off valve shall be installed
between the relief valve and the drain line. Valve lever
should be tripped at least once a year to ensure that
waterways are clear.
16
PRV
DISCHARGE
CONNECTION
Fig. # 8095.0
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