Potable Water and Space Heating
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.
CAUTION:
When this heater is used for both
potable water and space heating, observe the
following to ensure proper operation.
∆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 75 ft of tubing and fittings).
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 140°F. For higher than 140°F operation, or Hard water (>16 grains per gallon of total hardness), a water softener/treatment sys-
tem must be utilized.
Table I: Domestic Water Heater Flow Rate Requirements
Model No.
3–15 grains per gallon
Pump
HP
GPM
SHL
∆T
WH7-300A
1611
1/4
26
18.3
21.9
WH7-400A
1630
1/2
39
21.0
19.4
WH7-500A
1630
1/2
48
20.7
19.8
WH7-700A
1634
1
69
36.0
19.3
WH7-850A
1634
1
69
36.0
23.4
WARNING:
Plumbing between the heater and tank
in excess of 75 equivalent feet will require custom
pump selection. Damage due to low flow may occur
and is not a warrantable failure. Consult with your
local Raypak representative.
17
NOTE:
The 75 eq. feet of tubing typically represents
25 linear feet of tubing and 50 eq. feet of fittings.
Gas Supply
Gas piping
must
have a sediment trap ahead of the
heater gas controls,
and
a manual shut-off valve lo-
cated outside the heater jacket. It is recommended
that a union be installed in the gas supply piping adja-
cent to the heater for servicing. Refer to Table K for
maximum pipe lengths.
Gas Supply Connection
The heater must be isolated from the gas supply pip-
ing system by closing the upstream manual shut-off
valve during any pressure testing of the gas supply
piping system at test pressures equal to or greater
than 1/2 psi (3.45 kPa). Relieve test pressure in the
gas supply line prior to re-connecting the heater and
its manual shut-off valve to the gas supply line.
FAIL-
URE TO FOLLOW THIS PROCEDURE MAY
DAMAGE THE GAS VALVE
. Over-pressurized gas
valves are not covered by warranty. The heater and its
gas connections shall be leak-tested before placing
the appliance in operation. Use soapy water for leak
test. DO NOT use an open flame.
DANGER:
Make sure the gas on which the heater
will operate is the same type as specified on the rat-
ing plate.
CAUTION:
The heater must be disconnected from
the gas supply during any pressure testing of the gas
supply system at test pressures in excess of 1/2 psi
(3.45 kPa).
Summary of Contents for 300A
Page 44: ...WIRING DIAGRAM 44...
