Raypak 302-902 Section F Domestic Hot Water Piping, Potable Water And Space Heatingapplication

SECTION F: DOMESTIC HOT WATER PIPING

When designing the water piping system for domestic water applications, water hardness should be considered. Table F-1 indicates the suggested flow rates for soft, medium and hard water. Hardness is specified as grains per gallon.

TABLE F-1

DOMESTIC WATER HEATER

FLOWRATE REQUIREMENTS

DT = Temperature rise, degrees F GPM = Gallons/minute, flow rate

DP = Pressure drop, ft, through heat exchanger MPS = Minimum pipe size, NPT

SHL = System head loss, ft.

System head loss based on heater and tank placed no more than 5 ft. apart and equivalent length pipe/fittings as follows: 2” NPT = 75 ft.

* Must use optional cupronickel tubes.

POTABLE WATER AND SPACE HEATINGAPPLICATION

CAUTION:

When this heater is used for both -potable water and space heating- follow the steps below to insure proper operation.

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

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

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

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

SINGLE DOMESTIC HOT WATER HEATER WITH ONE STORAGE TANK

Hot Water Supply

City Water

System Return

Fig. #9224.1

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