tekmar 346 Power Manager - Manual (Page 4)

© 2008 D 346 - 04/08 4 of 8
On – Off Demand to tN4 Conversion
The 346 has four demand inputs and four tN4 bus outputs:
Inputs Outputs
Boiler Demand (0) tN4 Boiler Bus 0
Demand 1 tN4 Bus 1
Demand 2 tN4 Bus 2
Demand 3 tN4 Bus 3
A demand is a call for heat from a non-tN4 communicating
device. When a voltage between 24 to 260 V(ac) is applied
to a demand input, a tN4 message to activate the heating
occurs on the corresponding tN4 bus. The tN4 bus allows
for the demand input and tN4 devices (thermostats and
setpoint controls) to be mixed together on the same tN4
bus. The demand input on the 346 is fixed to tN4 address
01 on the bus that the demand is wired to.
When a demand is received, a tN4 message is sent to
request a desired Room temperature. The desired Room
temperature is used as a factor in the outdoor reset calculation
to determine the water temperature for a tN4 bus.
Demand
Apply
20 to 260 V (dc)
tN4 Message Created
Room Occupied
or
Room UnOccupied
tN4 C
tN4 Message to
System Control
Room Occupied and Unoccupied Settings
When a demand on the 346 is powered, a tN4 message is
generated and sent to the reset control. This tN4 message
requests a water temperature based upon the desired
Room Occupied or Room Unoccupied setting. The Room
Occupied temperature has four available preset temperatures
selected by the position of two switch settings. Likewise,
the Room Unoccupied temperature has four available
preset temperatures selected by the position of two other
switch settings. The Room Occupied or Room Unoccupied
temperature is selected by a schedule master. See Switch
Settings section for details.
Schedules
Use of schedules on the 346 requires the use of a schedule
master device. This can be a Timer 033, a tN4 Programmable
Thermostat, or a tN4 Setpoint Control 162. The schedule
master maintains the current time and sends messages
to schedule members to switch between Occupied and
Unoccupied settings.
Each of the four demand inputs can be configured to
respond to one of three schedule masters. When a demand
is received, the schedule master determines whether the
Room Occupied or at the Room Unoccupied temperature
in used in
the tN4 call for heat message.
The schedule master that each tN4 bus belongs to is
determined using a pair of switch setting positions. The
combinations are shown in the Switch Setting section of
the brochure.
If the schedule master uses a 4 event schedule (wake,
unoccupied, occupied, sleep), the wake time period causes
the 346 to operate at the Room Occupied temperature,
and the sleep time period causes the 346 to operate at
the Room Unoccupied temperature.
346
tN4 Schedule
Master
tN4 Bus
Auxiliary Pumps
The 346 includes three auxiliary pump inputs (terminal 4, 8
and 12) and three powered auxiliary pump outputs (terminals
25, 29 and 31). When the auxiliary pump input is powered
with 24 V (ac), the corresponding auxiliary pump output is
energized with 120 V (ac).
Aux tN4 C R
Pmp 1 1
4 5 6 7
ON
25 26
Aux Pump 1
Pmp N
Pump