Tekmar D 508, Data Brochure

Page: 2 / 12

© 2010 D 508 - 05/10 2 of 12
CYCLES PER HOUR
The thermostat operation is based on cycles per hour. The number of cycles per hour is adjustable
through the HEAT CYC setting in the
Adjust menu. During each cycle that heating is required,
the thermostat turns on the Heat relay for a calculated amount of time. This amount of time is
the “ON time”. The ON time is calculated based on the requirements of the zone. If the zone
requires more heating, the ON time is increased. If the zone requires less heating, the ON time
is reduced.
General
Display Symbols
Warning
Displays when an error exists.
Access Level
Displays when in the user
access level.
Heat One
Displays when the heat contact
is on.
In order to prevent short cycling of the heating relay, the
thermostat ensures that the relay remains on or off for
a minimum amount of time.
An AUTO CYC setting is available for the heating cycle.
This setting allows the thermostat to determine the
best number of cycles per hour that balances both
temperature swings and equipment cycles.
AUXILIARY SENSOR
The thermostat has a single built-in sensor to measure air temperature at the
thermostat. In addition to the built-in sensor, the thermostat has terminals to connect
one auxiliary sensor. This sensor can be either an indoor sensor, a slab sensor, or
an outdoor sensor.
Indoor Sensor
An indoor sensor is used to measure the air temperature in the zone that the thermostat
is controlling. The temperature being read by the indoor sensor is used in the calculations
of the ON time for the relay in the thermostat. This setting is made through the
Adjust
menu of the thermostat. If the built-in sensor is set to ON and the auxiliary sensor is set
to Indoor, the temperatures of the sensors are averaged and used to calculate the ON
time of the relay.
Slab Sensor
A slab sensor is used to measure the slab temperature in the zone that the thermostat
is controlling. The temperature being read by the slab sensor is used in the calculations
of the ON time for the Heat
relay and allows the thermostat to operate the slab between
the slab minimum and slab maximum settings.
⇐ Cycle Length ⇒
Time
off off off on on on
Cycles Per Hour