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Data Brochure Addendum

ManualsBrandsTekmar ManualsThermostats & ControlsSnow Detector & Melting Control - Outdoor Temp. Reset - Two Zone - Two Stage Boiler - Mixing
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- Data Brochure Addendum
Snow Detector & Melting Control 664
D 664A
06/04
1 of 2 © 2004 D 664A - 06/04
The tekmar Snow Detector & Melting Control 664 has been modified to include the following features:
• Temporary Idle
• Adjustable Warm Weather Shut Down
• View Mix Target Temperature
The changes are included in controls starting with Lot 17. The date code and lot number is listed on the right hand side of
the 664.
The temporary idle allows the control to enter the idle state for a set amount of time. If the snow ice detector does not detect snow
during the temporary idle period, the control then leaves the idle state and returns to the OFF state. This is useful in applications
where there is the possibility of snow and the slab can be pre-heated in order to have a short heat up time if snow is detected.
To enable a temporary idle, the Temporary Idle setting in the ADJUST menu must be set from OFF to the length of the temporary idle.
The DIP Switch must be set to IDLE DEMAND and the IDLE 1 or IDLE 2 setting must be set to a temperature. To activate a temporary
idle, a voltage between 24 and 240 V (ac) must be applied across the Melt/Idle Demand terminals for at least 4 seconds.
When a temporary idle is selected, the control has three available states: OFF, Temporary Idle, and Melting. The table below
describes the action of the control:
Features listed below have been added to the 664 Snow Detector & Melting Control. The sections in this addendum now supplement
the D 664 brochure dated 07/01.
The control has a warm weather shut down for each zone that prevents the control from entering the melt or idle modes in order to
conserve energy. While in WWSD, the word WWSD is displayed in the STATUS 1 or STATUS 2 items in the VIEW menu and the WWSD
pointer is on the display. The WWSD item in the ADJUST menu can be either set to Automatic or it can be set to a temperature.
Outdoor
Temperature
Slab
Temperature
MELT
IDLE
WWSD
CWCO
Control enters
Idle and waits
for Melt Enable
Added Features
Section A: Temporary Idle (TMPY IDL)
Control State Action Result
OFF External Idle Demand Temporary Idle
OFF Manual or Auto Melt Start Melting
Melting External Idle Demand Melting
Melting Manual or Auto Melt Start Melting
Melting Manual or Auto Melt Stop OFF
Temporary Idle Temporary Idle Expires OFF
Temporary Idle Manual or Auto Melt Start Melting
Temporary Idle Manual Melt Stop OFF
Section B: Warm Weather Shut Down (WWSD)
AUTOMATIC (AUTO)
There is a warm weather shut down for each zone. When both the slab temperature of a zone
and the outdoor temperature exceed the zone’s Melt temperature setting by more than 2°F
(1°C), the zone enters into WWSD. While a zone is in WWSD, the word WWSD is displayed in
the STATUS item of the appropriate zone in the VIEW menu. When both zones enter WWSD,
the 664 turns on the WWSD pointer in the display.
ADJUSTABLE WWSD
When the WWSD is set to a temperature, the WWSD occurs when the outdoor air temperature
exceeds the WWSD setting by 1° F (0.5°C) and when the slab temperature of a zone exceeds
34°F (1°C). The zone exits WWSD when the outdoor temperature falls 1°F (0.5°C) below the
WWSD setting or if the slab temperature of the zone falls below 34°F (1°C). This allows the
Melting Temperature setting to be set higher than the WWSD. This is useful where high slab
temperatures are required to melt the snow or ice. A good example of this is installations using
paving bricks on top of sand and concrete layers.

Summary of content (2 pages)