Raypak RP2100 Unithermgovernoroperation, Internal Automatic BY-PASS Valve, Plastic Header

UNITHERMGOVERNOROPERATION

CAUTION:

The patented Unitherm Governor is a thermostatic mixing valve specifically designed to maintain constant heater internal temperature between 105° to 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

In addition to the Unitherm Governor, a built-in automatic by-pass valve is provided in the in/out header. While the Unitherm Governor responds to the changes in water temperature in the heater, 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.

Fig.#2003

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

To Pool	From Pool
	AUXILLARY BYPASS 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.

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 heater. The maximum acceptable pressure relief valve setting is 125 psi.

A 3/4" NPT connection is provided in the plastic header for installation of a pressure relief valve. The valve shall be installed in a vertical position. Do not over tighten. Install pressure relief valve hand tight plus 1/2 turn.

PLASTIC HEADER

Pressure Relief Valve

PRV Discharge

Connection

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.

CAST IRON HEADERPressure Relief

Valve

PRV Discharge

Connection

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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