wirsbo DuoMix 201 Installation Instructions Manual Download Page 4

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DuoMix Installation Handbook

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Mix 1 Demand

Mix 2 Demand

Minimum

Maximum

Melting

Idling

CWCO

Slab Supply

Sensor

Slab Return

Sensor

Slab Sensor

View

Mix 1 Demand

Mix 2 Demand

Minimum

Maximum

Melting

Idling

CWCO

View

Mix 1 Demand

Mix 2 Demand

Minimum

Maximum

Melting

Idling

CWCO

Melting mode

Once in melting mode, the DuoMix 201 maintains the slab at the programmed

MELTING

temperature by controlling the speed of the injection pump 2 (

Var2 Pmp). Whenever the control

is in the melting mode, the mixing pump (

Mix2 Pmp) is turned on and the Melting pointer is

displayed.

Idling mode

When the melting system starts off from a cold temperature, the time required for the slab to
reach the melting temperature can be excessive. To decrease this start up time, the slab can
be maintained at an idling temperature until melting is required. The idling feature is also useful
for preventing frost and light ice formation. When the control is in idling mode, the slab is
maintained at the IDLING temperature and the

Idling pointer is turned on.

Warm Weather Cut Off (WWCO)

If the slab and outdoor temperatures rise above the

MELTING temperature, heating the slab is no longer required. The control therefore

shuts down the melting system. When the outdoor or slab temperature drops below the

MELTING temperature, the control exits WWCO

and continues with normal operation.

Cold Weather Cut Off (CWCO)

Maintaining the slab at a

MELTING or IDLING temperature in extremely cold weather can be

expensive and may even be impossible. The control therefore turns the melting system off
when the outdoor temperature drops below the

CWCO setting and turns on the CWCO pointer.

If the slab is at the desired

MELTING temperature, the control will not enter the CWCO mode.

If the an enable signal is given during the

CWCO mode, the control continues to melt once out

of the

CWCO mode.

Slab Protection

To protect the slab from cracking due to thermal stresses, the control limits the rate of heat
applied to the slab through a

∆

T MAX setting. The

∆

T represents the difference between the

measured slab supply and return fluid temperatures. If this temperature difference approaches
the

∆

T MAX setting, the control operates the variable speed injection pump 2 to maintain the

∆

T at the

∆

T MAX setting. The Maximum pointer is turned on when the target

∆

T is greater than

the

∆

T MAX setting.

Ramping the

∆

T during Melting System Start Up

When the control is in melting mode, the control maintains the maximum

∆

T and slowly

increases the slab temperature to prevent thermal shock of the slab.

Run Time

Prior to the control entering the snow melting mode, a

RUN TIME should be selected. The snow melting time will start counting down once

the slab is up to melting temperature. If the

Start button on the control or the Remote Display 040 is pressed while snow melting is enabled

and the slab is up to temperature, the run time counter is reset. Pressing the stop button on either control will end the snow melting
operation. Using the Snow Melting Enable Kit A3040039, pressing the button during warm up or run time will end the snow melt operation.

EXERCISING OF THE PUMPS

To prevent the pumps from seizing after long inactive periods, all pumps are turned on after every 3 days of no
operation. The

Mix1 Pmp and Mix2 Pmp pump relays are turned on for 20 seconds and the variable speed pump

outputs are ramped up to 100% speed. During exercising, the LCD screen flashes "EXERCISE" and the

Test LED

flashes. Exercising can be stopped by pressing the

Test button.

REMOTE DISPLAY A3040040 (tN2). AVAILABLE OCTOBER 1998

A Remote Display A3040040 can be used to duplicate the control display in a remote location.
All settings can be remotely adjusted.

SNOW MELT ENABLE KIT A3040039 (tN2)

The Snow Melt Enable Kit is used for snow melting applications. The kit includes a Remote
Start/Stop Module, Mixing 2 Return Sensor A3040071, and a Slab Sensor A3040072. When
a Remote Start/Stop Module is connected to the 201, the LED (Light Emitting Diode) flashes
green or red. When the button is pressed, the control enters the snow melting mode. During
slab warm up, the LED flashes green. Once the slab is up to temperature, the LED remains
green continuously. If an error occurs in the control, the LED flashes red.

Installation

Slab Sensor 072

Universal Sensor 071

A3040071

A3040072

A3040040

Item

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WWSD

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