John Wood FlowTHRU Storage Tanks - Manual (Page 4)

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Sizing The Hot Water System
Temperature of the system is controlled by the temperature
set point of the instantaneous water heater or boiler coil.
Given the limited storage capacity of the storage tank and
the maximum output of the tankless coil boiler or instanta-
neous water heater, large hot water draws significantly
exceeding the circulating loop flow rate may lead to a reduc-
tion in temperature of hot water delivered.
Plumbing Connections
For a temperature controlled instantaneous water heater it
is recommended to install the plumbing as shown in Figure
2. It is also recommended to set-up and control the IWH out-
let temperature to be at least 11°C (20°F) above tank ther-
mostat temperature. The recommended plumbing installa-
tion for a tankless coil boiler is shown in Figure 3. In this
case, because the tankless coil boiler is able to control only
the differential between inlet and outlet temperature, the
cold water entering the tankless coil boiler must be tem-
pered with hot water from the storage tank. As there is a
large variety of heat sources and control systems, please
contact your local distributor for the plumbing system to
identify the solution that best suits your application.
1. Ensure the storage tank is level before starting installa-
tion.
2. Install a circulation loop as shown using 19mm (3/4 in.)
copper piping.
3. If the heating source is a tankless coil boiler go to step
4. If a temperature controlled IWH is used as a heat
source, install the combination inlet/drain valve in one
“arm” of a tee connected to the lower storage tank fit-
ting. Connect the cold water supply piping to the inlet of
the combination inlet/drain valve. Connect the other
“arm” of this tee to the IWH inlet line and place the cir-
culating pump in this line. Connect the IWH outlet to the
upper storage tank side fitting (see Figure 2). Proceed
to step 5.
4. For a tankless coil boiler install the combination
inlet/drain valve in the lower storage tank fitting.
Connect the inlet of the combination inlet/drain valve to
the hot outlet of the tankless coil boiler. In this instance
the “leg” of a tee should connect to the cold water sup-
ply line, one “arm” connects to the circulator pump and
the other “arm” to the inlet of the tankless coil boiler. The
circulator pump connects to the upper side fitting.of
storage tank (see Figure 3).
FROM IWH
TO IWH &
CIRCULATOR
PUMP
T&P VALVE
HOT
WATER
PIPE INSULATION
COLD IN
THERMOSTAT
WITH HIGH-
LIMIT SWITCH
DRAIN VALVE FLOOR DRAIN
DRAIN PAN
NOTE ORIENTATION
OF J-TUBE
Figure 1 Main Parts and Features for Connection to a
Temperature Controlled IWH
WARNING
The water heating source piping and components con-
nected to the tank must be suitable for potable water use.
TOXIC chemicals such as used for boiler treatment must
not be introduced into the tank.
Important
Do not apply heat directly to tank fittings when making
sweat connections. They contain non-metallic material.
Figure 2 Single Storage Tank Plumbing for a
Temperature Controlled IWH
DRAIN
STORAGE
TANK
TEMPERATURE
CONTROLLED
IWH
HOT
T&P
VALVE
CIRCULATOR
PUMP
EXPANSION TANK
(OPTIONAL)
COLD
COLD
MIXING
VALVE
CHECK
VALVE
T
Figure 3 Single Storage Tank Plumbing for a Non-
Temperature Controlled Tankless Coil Boiler
COMBINATION
INLET/DRAIN VALVE
STORAGE
BOOSTER
TANK
NON-TEMPERA-
TURE CON-
TROLLED TANK-
LESS COIL BOILER
HOT
HOT
T&P VALVE
CIRCULATOR
PUMP
CHECK VALVE EXPANSION TANK (OPTIONAL) PRESSURE
REGULATOR
(OPTIONAL)
COLD
T
COLD
MIXING
VALVE