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INTERNAL AUTOMATIC
In addition to the Unitherm Governor, a
BYPASS DISC
SPRING
BYPASS
BODY
To conform to local building codes, it may be necessary 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 heater. The maximum acceptable pressure relief valve setting is 125 psi.
A 3/4" NPT connection is provided in the plastic header forinstallationofapressurereliefvalve. Thevalveshallbe installed in a vertical position. Do not over tighten. Install pressure relief valve hand tight plus 1/2 turn.
POLYMER HEADER
Pressure Relief Valve
PRV Discharge
Connection
EXTERNAL AUXILIARY BYPASS VALVE (Where Required)
An auxiliary bypass valve should be used when flow rates exceed 125 GPM (usually a high performance pump size larger than two horsepower 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 50°F. It also serves to eliminate needless pressure drop through the heater and accompanying reduction in the flow rate to the spa jets, etc.
From Heater | To Heater | Fig.#2003 |
Inlet/Outlet Header
Fig. #2004
A 3/4" NPT connection is provided in the header for installation of a pressure relief valve. The valve shall be installed in a vertical position.
ASME HEADER
(Cast Iron)Pressure Relief
Valve
PRV Discharge
Connection
To Pool | From Pool |
AUXILIARYBYPASS VALVE |
|
(DO NOT USE GATE VALVE) | Fig. # 8150.0ss |
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.
Inlet/Outlet Header | Fig. # 8095.0 |
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 shutoff 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.
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