GSW FlowThru warranty Sizing The Hot Water System, Plumbing Connections

Sizing The Hot Water System

1. Ensure the storage tank is level before starting installa-

Temperature of the system is controlled by the temperature

tion.

set point of the instantaneous water heater or boiler coil.

2. Install a circulation loop as shown using 19mm (3/4 in.)

Given the limited storage capacity of the storage tank and

copper piping.

the maximum output of the tankless coil boiler or instanta-

3. If the heating source is a tankless coil boiler go to step

neous water heater, large hot water draws significantly

4. If a temperature controlled IWH is used as a heat

exceeding the circulating loop flow rate may lead to a reduc-

source, install the combination inlet/drain valve in one

tion in temperature of hot water delivered.

“arm” of a tee connected to the lower storage tank fit-

ting. Connect the cold water supply piping to the inlet of

Plumbing Connections

the combination inlet/drain valve. Connect the other

“arm” of this tee to the IWH inlet line and place the cir-

WARNING

culating pump in this line. Connect the IWH outlet to the

upper storage tank side fitting (see Figure 2). Proceed

The water heating source piping and components con-

nected to the tank must be suitable for potable water use.

to step 5.

TOXIC chemicals such as used for boiler treatment must

4. For

a tankless

coil boiler install the combination

not be introduced into the tank.

inlet/drain valve in the lower storage tank fitting.

Connect the inlet of the combination inlet/drain valve to

For a temperature controlled instantaneous water heater it

the hot outlet of the tankless coil boiler. In this instance

the “leg” of a tee should connect to the cold water sup-

is recommended to install the plumbing as shown in Figure

ply line, one “arm” connects to the circulator pump and

2. It is also recommended to set-up and control the IWH out-

the other “arm” to the inlet of the tankless coil boiler. The

let temperature to be at least 11°C (20°F) above tank ther-

circulator pump

connects to the upper side

fitting.of

mostat temperature. The recommended plumbing installa-

storage tank (see Figure 3).

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-

COLD

MIXING

pered with hot water from the storage tank. As there is a

HOT

VALVE

large variety of heat sources and control systems, please

TEMPERATURE

CONTROLLED

contact your local distributor for the plumbing system to

IWH

identify the solution that best suits your application.

STORAGE

T&P

VALVE

TANK

Important

Do not apply heat directly to tank fittings when making

sweat connections. They contain non-metallic material.

T

CIRCULATOR

DRAIN

CHECK

EXPANSION TANK

PUMP

HOT

VALVE

(OPTIONAL)

WATER

NOTE ORIENTATION

COLD

OF J-TUBE

Figure 2 Single Storage Tank Plumbing for a

Temperature Controlled IWH

T&P VALVE

CHECK VALVE

EXPANSION TANK (OPTIONAL)

PRESSURE

PIPE INSULATION

REGULATOR

(OPTIONAL)

CIRCULATOR

PUMP

COLD

FROM IWH

MIXING

HOT

VALVE

COLD

THERMOSTAT

WITH HIGH-

LIMIT SWITCH

TO IWH &

T&P VALVE

CIRCULATOR

PUMP

HOT

STORAGE

BOOSTER

TANK

T

NON-TEMPERA-

DRAIN PAN

COMBINATION

TURE CON-

INLET/DRAIN VALVE

TROLLED TANK-

COLD IN

LESS COIL BOILER

DRAIN VALVE

FLOOR DRAIN

Figure 1 Main Parts and Features for Connection to a

Figure 3 Single Storage Tank Plumbing for a Non-

Temperature Controlled IWH

Temperature Controlled Tankless Coil Boiler

4

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