Raypak 300 Hydronic Heating, Relief Valve Installation and Piping, Temperature & Pressure Gauge

Relief Valve Installation and Piping

WARNING: Pressure relief valve discharge piping must be piped near the floor and close to a drain to eliminate the potential of severe burns. Do not pipe to any area where freezing could occur. Refer to local codes.

The heater is supplied with a Section IV “HV” stamped relief valve sized for the full input of the unit. The relief valve assembly is shipped loose and must be mount- ed directly to the heater outlet. No valve shall be installed between the heater and the relief valve. The relief valve shall be mounted with its spindle vertical (see Fig. 1, 2 and 3 on page 6). Relief valve discharge piping shall provide no less than the cross sectional area of the relief valve outlet and must be routed to a safe point of discharge. Installation must comply with all national, state and local codes.

WARNING: The pressure relief valve must be installed at the outlet of the boiler. No valve is permitted to be installed between the boiler and the relief valve.

Temperature & Pressure Gauge

The temperature and pressure gauge is shipped loose for field installation and must be installed within 12 inches of the boiler outlet (if possible) in an easily readable location. Installation must comply with ASME Section IV as well as all applicable national, state and local codes.

Hydrostatic Test

Unlike many types of heaters, this heater does not re- quire hydrostatic testing prior to being placed in operation. The heat exchanger has already been fac- tory-tested and is rated for 160 psi operating pressure. However, Raypak does recommend hydrostatic test- ing of the piping connections to the heater and the rest of the system prior to operation. This is particularly true for hydronic systems using expensive glycol- based anti-freeze. Raypak recommends conducting the hydrostatic test before connecting gas piping or electrical supply.

Leaks must be repaired at once to prevent damage to the heater. NEVER use petroleum-based stop-leak compounds.

To perform hydrostatic test:

1.Connect fill water supply. With bleed valve open, fill heater with water. When water flows from bleed valve, shut off water. Close bleed valve. Carefully fill the rest of the system, making sure to eliminate any entrapped air by using high-point vents. Close feed valve. Test at standard operating pressure for at least 24 hours.

2.Make sure constant gauge pressure has been maintained throughout test.

3.Check for leaks. Repair if found.

Hydronic Heating

Pump Selection

In order to ensure proper performance of your heater system, you must install a correctly-sized pump. Ray- pak recommends designing for a ∆T within the range of 20°F to 40°F (5°C to 20°C). See Table G for accept- able flow rates for each model (∆T is the temperature difference between the inlet and outlet water when the heater is firing at full rate).

Feedwater Regulator

Raypak recommends that a feedwater regulator be in- stalled and set at 12 psi minimum pressure at the highest point of the system. Install a check valve or back flow device upstream of the regulator, with a manual shut-off valve as required by local codes.

Piping

All high points should be vented. A heater installed above radiation level must be provided with a low wa- ter cut-off device (sales order option F-10). This heater, when used in connection with a refrigeration system, must be installed so that the chilled medium is piped in parallel with the heater with appropriate valves to prevent the chilled medium from entering the heater.

The piping system of a hot water heater connected to heating coils located in air handling units where they may be exposed to circulating refrigerated air, must be equipped with flow control valves or other automatic means to prevent gravity circulation of the heater water during the cooling cycle. It is highly recommend- ed that the piping be insulated.

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