tekmar 362 Mixing Control Installation User Manual

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Mix

Demand

24 to 240 V (ac)

Sequence, Section C2

RUNNING TIME (RUN TIME)

The running time is the length of time that the snow melting system operates once the slab has reached the melting temperature. During
the time that the slab is approaching the melting temperature, the RUN TIME does not decrease. Once the slab has reached the melting
temperature, the RUN TIME begins counting down. When the RUN TIME reaches 0:00 as displayed by the SNOWMELT item in the

View

menu, the 362 has finished Melting.

WARM WEATHER SHUT DOWN (WWSD)

When both the slab temperature and the outdoor temperature exceed the
Melting temperature by more than 1.5˚F (1˚C), the control enters into a
WWSD. In a WWSD, the snow melting system is shut down in order to
conserve energy.

COLD WEATHER CUT OUT (CWCO)

Maintaining the slab at either the Melting or Idling temperature during extremely cold temperatures can be expensive or impossible. The
control shuts off the snow melting system once the outdoor air temperature drops below the Cold Weather Cut Out (CWCO) temperature.
While the control is in a CWCO, the word CWCO is displayed in the SNOWMELT item in the View menu. If the control had been started
prior to the CWCO, it resumes the melting mode once the outdoor air temperature rises above the CWCO temperature.

BOILER OPERATION

Refer to section D for a description of the boiler operation.

BOILER PROTECTION (Boil MIN)

The 362 ensures that the boiler supply water temperature remains above
the Boil MIN setting. If the boiler supply water temperature begins to drop
due to the slab return temperature, the mixing device is throttled back to
allow the boiler to recover. This minimizes the time that the boiler operates
below its condensing temperature and prolongs the life of the boiler. The
362 can only provide boiler protection if the Boil SENS item is set to SUP
or RET. The 362 cannot provide boiler protection if the Boil SENS item is
set to NONE.

SNOW MELTING OVERRIDE

Internal Override

If the AWAY setting is selected in the Schedule menu, the system is shut down. Both the

Melting and Idling temperatures are ignored

as long as the control remains in the AWAY mode. The

Setback / N

one DIP does not matter for internal overrides.

External Override

While in Mode 2, any signal received on the UnO Sw and COM terminal (16 and 17) is ignored and does not affect the operation of
the control.

MIXING PUMP OPERATION (Mix Pmp)

The Mixing Pump (Mix Pmp) contact closes and remains closed as long as the control is either in the Melting or Idling mode. The Mixing
Pump contact shuts off if the control is in WWSD, CWCO, or if there is no call for Melting or Idling.

PURGE (PURGE)

The Mixing Pump (Mix Pmp) continues to operate for the set PURGE time after the control finishes operation.

Section C2: Snow Melting Enable (Mode —2—)

There are three methods in which the snow melting system can be enabled on the Mixing Control 362. Either an

External Demand, a

Remote Start / Stop Module 039 or a Remote Display Module 040 can be used to start the snow melting system.

EXTERNAL DEMAND

An external snow melting demand is generated when a voltage between
24 and 240 V (ac) is applied across

Mix Demand (1 and 2) terminals. An

external demand must be present for at least 4 seconds in order to start the
snow melting system. Once started, the slab temperature is increased to
the MELTING setting and maintained at the melting temperature until the
Run Time reaches 0:00. If the Run Time reaches 0:00 and the external
demand is still present, the control continues at the melting temperature
until the external demand is removed or the system is otherwise stopped.