tekmar 545 Thermostat Installation - Manual (Page 27)

27 of 40 © 2008 D 545 - 07/08
Fin–tube Convector (CONV)
A convector terminal unit is made up of a heating element
with fins on it. This type of terminal unit relies on the natural
convection of air across the heating element to deliver
heated air into the space. The amount of natural convection
is dependant on the supply water temperature to the heating
element and the room air temperature.
Radiator (RAD)
A radiator terminal unit has a large heated surface that is
exposed to the room. A radiator provides heat to the room
through radiant heat transfer and natural convection.
Heating Operation Section F
One-Stage PWM Heating
W
a
rmer
Set
Heat
Cycle Length
Heat
Reset Water
Temperature
100%
On Time
85%
On Time
90%
On Time
Indoor Temperature Feedback
Indoor feedback applies when the thermostat is connected to
a tN4 network with a tN4 System Control. Indoor temperature
feedback fine tunes the water temperature of the system
based on the requirements of the thermostats.
Each thermostat tells the tN4 System Control the water
temperature that it requires to heat its zone.
•
• If the zone is becoming too cool, the thermostat asks
for a higher water temperature.
• • If the zone is becoming too warm, the thermostat asks
for a cooler water temperature.
The tN4 System Control provides the highest water
temperature required by all of the thermostats.
•
• The thermostat with the highest water temperature
requirement stays on 100% of its cycle.
• • The remaining thermostats stay on for a percentage of
their cycles.
Floor Sensor Only
When operation with only a floor sensor, the on time for
the Heat 1 relay is calculated to satisfy the requirements
of the floor sensor. The floor temperature varies between
the floor minimum and the floor maximum settings.
Note: Operation with only a floor sensor can lead to either
overheating or underheating of the space.
Room and Floor Sensor
When operating with both a room and floor sensor, the
thermostat calculates an on time for the Heat 1 relay to
satisfy the floor sensor and an on time to satisfy the room
sensor. The Heat 1 relay operates for the longer of these
two on times.
During light heating loads, overheating can occur due to
the minimum floor temperature setting.
During heavy heating loads, the maximum floor temperature
setting limits the on time of the Heat 1 relay. In this situation,
underheating can occur.
Baseboard (BASE)
A baseboard terminal unit is similar to a radiator, but has
a low profile and is installed at the base of the wall. The
proportion of heat transferred by radiation from a baseboard
is greater than that from a fin-tube convector.
Other (OTHR)
In applications where a non-hydronic heating system
(furnace, electric baseboard, etc.) is installed, set the
terminal unit to other.
Furnace (FURN)
When you are operating a furnace, or similar equipment,
and require the fan to operate with the heat relay contact,
set the terminal unit to furnace.
One Stage Heating
Room Sensor Only
When operating with only an room sensor, the on time for
the Heat 1 relay is calculated to satisfy the requirements
of the room sensor.