Raypak 300, 850 operating instructions Potable Water and Space Heating

Fig. 9: Single Domestic Hot Water Heater and Storage

Tank

NOTE: If local codes require a vacuum relief valve, acquire one locally and install per valve manufacturer’s instructions.

Potable Water and Space Heating

CAUTION: When this heater is used for both potable water and space heating, observe the following to ensure proper operation.

1.All piping materials and components connected to the water heater for the space heating application shall be suitable for use with potable water.

2.Toxic chemicals, such as used for boiler treatment, shall not be introduced into the potable water used for space heating.

3.If the heater will be used to supply potable water, it shall not be connected to any heating system or components previously used with a non-potable water heating appliance.

4.When the system requires water for space heating at temperatures higher than 140°F (60°C), a means such as a mixing valve shall be installed to temper the water in order to reduce scald hazard potential.

Fig. 10: Multiple Boilers — Reverse Return,

Primary/Secondary Piping with Indirect DHW

Model		Soft (0–4 grains per gallon)				Medium (5–15 grains per gallon)
No.	∆T	gpm	∆P	MTS	SHL	∆T	gpm	∆P	MTS	SHL
300	30	19	8	1.5	10	20	28	17	1.5	20
500	30	31	7	2	8	20	47	16	2	18
850	30	53	17	2	20	20	80	40	2	46

∆T = Temperature rise, °F.

∆P = Pressure drop through heat exchanger, ft.

SHL = System head loss, ft (based on heater and tank placed no more than 5 ft apart and equivalent length of 25 ft of tubing). gpm = Gallons per minute, flow rate.

MTS = Minimum tubing size.

CAUTION: For scale free operation with Medium water (5–15 grains per gallon of total hardness), the operating control must NOT be set higher than 130°F. For higher than 130°F operation, or Hard water (>16 grains per gallon of total hardness), a water sof- tener/treatment system must be utilized.

Table H: Domestic Water Heater Flow Rate Requirements

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