Raypak 122-322 manual Hydronic Heating, Hydrostatic Test, Low Temperature System, Pump Selection

Hydrostatic Test

Unlike many other types of heaters, Raypak heaters do not require hydrostatic testing prior to being placed in operation. The heat exchanger has already been factory-tested and is rated for 160 PSI maximum oper- ating pressure. However, Raypak does recommend hydrostatically testing 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 antifreeze. Raypak recom- mends 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.

1.Connect fill water supply. Fill heater with water (be sure bleed valve is open). When water flows from bleed valve, shut off water. Close bleed valve. Carefully fill the rest of the system, being 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.

Low Temperature System

Heater requires minimum inlet temperature of 105°F. Consult the following sections for piping details.

Temperature & Pressure Gauge

The temperature and pressure gauge is factory- mounted in the in/out header.

Hydronic Heating

Pump Selection

In order to ensure proper performance of your boiler system, you must install a properly sized pump. Raypak recommends using a 20°F Delta T as design Delta T. (Delta T is the temperature difference between the inlet and outlet water when the heater is firing at full rate). If a Delta T larger than 20°F is necessary, see Table F for minimum flow rate requirements.

Pressure Drop in Feet of Head Feedwater Regulator

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

Model	10°F ΔT		20°F ΔT		30°F ΔT			Min. Flow			Max. Flow
No.	gpm	ΔP (ft)	gpm	ΔP (ft)	gpm	ΔP (ft)	gpm		ΔP (ft)	ΔT	gpm	ΔP (ft)	ΔT
122	20	2.5	10	<1.0			10*		<1.0	20	30	5.3	7
162	27	4.5	13	1.10			10		<1.0	27	30	5.4	9
202	34	7.2	17	1.85	11	<1.0	10		<1.0	34	30	5.5	11
242	40	10.0	20	2.65	14	1.3	10		<1.0	40	44	11.8	9
322			27	4.70	18	2.2	14		1.4	40	44	12.2	12

*Flow switch (when used) will not activate at less than 12 gpm. NOTE: Basis for minimum flow - 10 gpm or 40° Delta T maximum flow - 44 gpm, except for 1.25” header.

Table F: Heater Rates of Flow and Pressure Drops

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