John Wood Commercial - AJWS - Manual (Page 9)

Note: Inlet and outlet piping connections cannot be mixed.
For example, a top inlet connection must use a top outlet
connection.
2.
The installation of unions in both the hot and cold water
supply lines is recommended for ease of removing the
water heater for service or replacement.
3. Since most commercial installations utilize higher tem-
peratures, the use of a tempering valve is strongly
recommended in all domestic hot water lines (i.e.
public restroom sinks, etc).
4. If installing the water heater in a closed water system,
install an expansion tank in the cold water line as spec-
ified under “Closed System/Thermal Expansion” (Page
12).
5. Install a shut-off valve in the cold water inlet line. It
should be located close to the water heater and be eas-
ily accessible. Know the location of this valve and how
to shut off the water to the heater.
6. The water heater is shipped with a factory-installed
Temperature and Pressure Relief Valve. Install a dis-
charge line in the opening in the T & P valve (see
instructions on Page 13).
7. After piping has been properly connected to the water
heater, remove the aerator at the nearest hot water
faucet. Open the hot water faucet and allow the tank to
completely fill with water. To purge the lines of any
excess air, keep the hot water faucet open for 3 minutes
after a constant flow of water is obtained. Close the
faucet and check all connections for leaks.
Space Heating
If this unit is to be used to supply both space heating and
domestic potable (drinking) water then the following instruc-
tions must be followed:
1.
All piping and components used must be suitable for
use with domestic (potable) drinking water.
2. Do not use piping or components that have been con-
nected to a nonpotable system or treated with chro-
mates or other toxic chemicals. Do not add any chemi-
cals to the water heater piping.
3. If system requires temperatures in excess of 49°C
(120°F) install a tempering valve, per the manufacturers
instructions, in the domestic (potable) hot water line to
limit the risk of scalding (See Figure 5).
4. Be sure to follow the manual(s) shipped with the heat-
ing system. Also follow any state or local codes.
Tempering Valve Installation
A Tempering Valve should be installed per the manufactur-
er’s instructions in the hot water line. See Figure 5 for sam-
ple tempering valve installation.
Please note the following:
DO NOT install this water heater with iron piping. The sys-
tem should be installed only with piping that is suitable for
potable (drinkable) water such as copper, CPVC, or poly-
butylene.DO NOT use PVC water piping.
DO NOT use any pumps, valves, or fittings that are not
compatible with potable water.
DO NOT use valves that may cause excessive restriction to
water flow. Use full flow ball or gate valves only.
DO NOT use 50/50 tin-lead solder (or any lead based sol-
der) in potable water lines. Use 95/5 tin-antimony or other
equivalent material.
DO NOT tamper with the gas valve/thermostat, igniter, or
temperature and pressure relief valve. Tampering voids all
warranties. Only qualified service technicians should serv-
ice these components.
DO NOT use with piping that has been treated with chro-
mates, boiler seal, or other chemicals.
DO NOT add any chemicals to the system piping which will
contaminate the potable water supply.
9
Follow the tempering
valve manufacturer’s
instructions.
Cold
Water
Inlet
Hot
Water
Outlet
Tempered water
to fixtures
Tempering valve
(Set to 120°F)
Figure 5: Tempering Valve
Water Heater
Model Base #
Dip Tube
Inlet Tube
(Optional Front)
Inlet Tube
(Optional Back)
75-125 60238 60239 60239
80-199 60053 60057 60057
80-250 60053 60057 60057
100-199 71325 75085 75086
100-270 71325 75085 60023
75-300 60053 60057 60057
75-360 N/A 60194 60195
75-399 N/A 60194 60195
75-300NO
x N/A 60194 60195
75-350NO
x N/A 60194 60195
Table 5: Dip Tube Useage
Hot Water
Outlet
Unions
Cold Water
Inlet Valve
Discharge line
6” max. above
drain
Cold Water
Supply to Fixtures
In a closed system use a
Thermal Expansion Tank
Temperature and
Pressure Relief Valve
Drain line
3/4” ID min.
Drain
Metal drain
pan 1 3/4”
depth max.
Pressure Reducing
Valve with Bypass
Main Water
Supply
Figure 4: Water Piping Installation
Massachusetts:
Install a vacuum relief
in cold water line per
section 19MGL 142
Drain line
19mm (3/4 in)
ID min.
Discharge line
152mm (6 in)
max. above
drain
Metal drain
pan 45mm
(1-3/4 in.)
depth max.