Bradford White TW-55X-78B-3X User Manual

INTEGRATED MIXING DEVICE (IMD)

INSTALLATION AND OPERATING INSTRUCTION MANUAL

For your family’s comfort, safety and convenience, it is recommended this IMD be
installed and serviced by a plumbing professional.

This manual will explain in detail the installation and maintenance of the integrated mixing device.
We require that you carefully read this manual and refer to it if questions arise.

PRE-INSTALLATION

The following steps should be taken to ensure proper conditions for operation:

Note all site parameters (pressure, temperature, etc.) and check against the integrated mixing
device (IMD) specifications listed in Table 1. All specifications must be met prior to installing the
IMD.
This IMD MUST NOT be subjected to heat during installation as this may damage the internal
parts.

CAUTION

If sweat fittings are to be used, DO NOT apply heat to the fittings on top of the
water heater. Sweat the tubing to the adapter before fitting the adapter to the
water connections. It is necessary that heat is not applied to the fittings to ensure
appropriate operation.

The valve MUST NOT be allowed to freeze. If the IMD is installed in a potentially freezing
situation, suitable insulation must be fitted to prevent damage.
DO NOT use excess thread sealant (in liquid, tape or other form) as this may cause the IMD to
fail. The installer must ensure that thread sealant does not get into the internal parts.
In order to install this IMD on a unit with a blower mounted on top, it is necessary to remove the
blower prior to installation and replace the blower after installation of this IMD.
If the water heater is gas-fired, the IMD must be installed before the draft hood.
This manual is meant to be used in conjunction with the installation and operation manual
(owners manual) for the water heater.
Toxic chemicals, such as used for boiler treatment, shall not be introduced into IMD used for
space heating. This IMD may never be connected to any existing heating system or
component(s) previously used with a non-potable water heating system.

Leave a copy of this instruction manual with the water heater for future reference.

Recommend to the user that the IMD be checked annually to ensure its continued function.

Page 1 238-47870-00C 08/09

INTEGRATED MIXING DEVICE - IMD SPECIFICATIONS

Table 1

Mixed water supply temperature range

100 - 145°F (38 - 63°C)
Water heater outlet temperature range 100 - 180°F (38 - 82°C)
Cold water inlet temperature range 33 - 80°F (1 - 27°C)

Device temperature stability (nominal)
Temperature differential

(between hot supply and outlet temperature)

± 3°F (± 1.7°C) at 3 - 5 gpm (see note 1)

± 5°F (± 3.0°C) at 5 - 40 gpm (see note 1)

27°F (15°C) (see note 2)

Hydrostatic pressure 150 psi (1034 kPa) maximum
Permitted supply pressure variation
Flow rate (min)
Flow rate (max)

± 10% (see note 3)

0.25 gpm (0.9 L/m)

19.2 gpm (72.0 L/m)

2.8 (mixed temp. of 95°F)

Cv

1.8 (mixed temp. of 120°F)

1.3 (mixed temp. of 140°F)

Notes:

1. As tested in accordance with ASSE 1017.

2. This is the minimum difference required between the mixed water supply temperature and the
water heater outlet temperature to enable the IMD to function correctly and ensure shut-off of
outlet flow in the event of cold supply failure.

3. Maximum permitted variation in either supply pressure in order to control the mixed water supply
temperature to within ± 3°F. Excessive changes in supply pressures may cause changes in
mixed water supply temperature.

Mixed TemperatureMixed Temperature

of 140°F

60

50

40

30

20

Pressure Drop (psi)

10

5

of 120°F

Mixed Temperature

of 95°F

1234567891011121314151617181920

Flow (gpm)

Page 2

Remove all components from the
package and check that all required
components are included. The required
components are: mixing device, cold
water tee, flexible metal connector and
thermostrip (see Figure 1).

This kit may have two flexible
connectors provided for water heaters
with top water course connections at 8
inch and 11 inch spacing. Use the
appropriate flexible metal connector.

Instructions

Mixing
device

Flexible metal

connector

Cold water tee

Figure 1

WATER CONNECTIONS

The mixing device, cold water tee, flexible metal connector and thermostrip are integral parts of the
water heater. This system improves hot water deliverability and must be installed. The integrated
appliance is designed for a maximum working pressure of 150 p.s.i. (1034 kPa). Refer to the
“Water Connections” section of the installation and operation instruction manual supplied with the
water heater for additional instructions.

The mixing device is equipped with a ½” NPT alternate hot water
outlet that draws unmixed very hot water from the tank. This outlet
should be used if unmixed very hot water is needed at specific
fixtures (laundry, dishwasher, etc…). It is also equipped with a ½”
NPT optional recirculation inlet that must be utilized in conjunction
with a check valve if a recirculation loop is used (see Figure 2).

(MIX) ¾" NPT

WARNING

If recirculation loop water is returned
to the water heater at any location
other than the optional recirculation
inlet, unmixed very hot hot water is
exposed to the recirculation loop.
Do not return recirculation loop to
any other location other than “R”
inlet of the mixing device.

Mixed water

IMD Components

(COLD) Cold water

inlet from cold

outlet

Thermostrip

water tee

(AH) ½" NPT

Alternate hot

water outlet

Mixing Device

Page 3

Figure 2

(R) ½" NPT

Optional

recirculation inlet

(HOT) ¾" NPT Hot

water inlet from

water heater