Electrical wiring, Filling, Iv) operation – John Wood FlowTHRU Storage Tanks User Manual

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5. Pay attention to the desired flow direction when

installing the circulator pump. If the pump does not have
a check valve embedded install one to ensure the
desired flow direction is maintained during system oper-
ation.

6. Install a mixing valve with the hot port going to the top

tank fitting. Connect the domestic hot water supply line
to the mixing port of the mixing valve. Connect the cold
port of the mixing valve to the cold water supply line and
place a shut-off in this line. Most mixing valves do not
operate properly if the pressure differential between hot
and cold port is too high. If this happens, lower mixed
water temperature will be provided. The shut-off valve
should be used to adjust this pressure differential. Set
the mixing valve outlet temperature to 49°C (120°F) to
avoid scalding.

7. A check valve may be installed in the cold water line

before the connecting tee.

NOTE: The check valve can often be noisy and cause
reduced supply pressures. For multiple storage tank sys-
tems, check valves must be installed to prevent the circula-
tor pump from pumping hot water into another tank and
overheating it.

8. The use of a pressure regulator is optional, but recom-

mended when the cold supply pressure is over 80 psi.
Reducing the inlet pressure to 45-60 psi will reduce
probability of relief valve discharge due to thermal
expansion.

9. The water utility supply meter may contain a check

valve, back-flow preventer or water pressure-reducing
valve. This will create a closed water system. During a
heating cycle, water expands creating a pressure
buildup in the water system. A Temperature and
Pressure (T&P) Relief Valve must be installed (150 psi
maximum pressure). See preceding section. If the T&P
valve discharges periodically, it may be due to thermal
expansion in a closed system. To prevent this condition
and to reduce the possible buildup of lime on the T&P
Relief Valve seat, install a thermal expansion tank in the
circulating loop as shown in Figure 2 and 3.

10. Some jurisdictions require a Vacuum Relief Valve to be

installed. Such a valve allows air to enter the piping sys-
tem thus preventing vacuum conditions that could
siphon water from the system. Check local code
requirements.

Electrical Wiring

Electrical wiring must be in accordance with local codes or,
in the absence of such codes, with the “Canadian
Electrical Code, Part I, (C22.1)” or the “National
Electrical Code, (NFPA 70)” as applicable.
1. Supply 110/120 volts, 60Hz power, to the junction box

located at the top of the tank.

2. Connect the circulator pump in series with the thermo-

stat as shown in Figure 4.

3. A ground wire must be supplied from the ground con-

nection at the service panel to the ground screw at the
junction box.

4. The thermostat is rated for a maximum inductive current

of 7 FLA at 120 VAC. Do not exceed this rating for the
circuit.

5. Do not install or connect electrical heating elements to

this tank.

Filling

NOTE: When filling, avoid water leakage. Do not allow the
insulation of the tank to get wet as water can cause electri-
cal malfunction or reduce the effectiveness of the insulation.
1. To insure complete filling of the tank, allow air to exit by

opening a hot water faucet that is served by the tank
and is some distance away from the heater.

2. Ensure the storage tank drain valve is closed.
3. Open the cold water supply valve and fill the tank and

piping system with water. When an uninterrupted
stream of water, without apparent air bubbles, flows
from the open hot water faucet, the system is full.

4. Close the open hot water faucet. Check the system for

leaks, repair as necessary and retest.

5. Connect a hose to the drain valve and route to a suit-

able drain. Open the drain valve and let water run to
flush out any foreign matter that may have entered the
system. Once flushed, close the drain valve and dis-
connect hose.

1. Follow boiler or instantaneous water heater installation

and operating instructions.

2. Fill the tank (see “Filling” section).
3. The boiler or instantaneous water heater should be set

to provide at least 11°C (20°F) higher water temperature
than the temperature setting of the storage tank.

4. Turn power on, check for proper operation of boiler or

instantaneous water heater and storage tank.

Figure 4 Wiring Diagram

WHITE

BLACK

GROUND

CIRCULATOR PUMP

(FIELD PROVIDED)

JUNCTION BOX

(AT CASING TOP)

IV) OPERATION