© 2018 tekmar 304P_D - 12/18
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User Interface - Indicator LED
Sequence of Operation
Zone Operation
When a thermostat calls for heat by closing the R and W
terminals:
• 115 V (ac) is applied to the corresponding circulator pump.
• The corresponding zone indicator LED is turned on.
Boiler Operation
When a thermostat calls for heat by closing the R and W
terminals:
• The boiler end switch XX is closed to fire the boiler.
• The RoomResponse
TM
0-10 V (dc) or 4-20 mA signal is sent
to a modulating-condensing boiler.
DHW Operation
Many modulating-condensing boilers have multiple temperature
call inputs. Wire the DHW end switch to input recommended
in the boiler's manual.
When a zone 1 calls for heat by closing the R and W terminals:
• The DHW end switch is closed to fire the boiler at the DHW
temperature.
• The Mod Boiler output is changed to 10 V (dc) or 20 mA.
Master / Member DIP Switch
• Allows for unlimited expansion using additional Switching
Relays and/or Zone Valve Controls.
• The Master Switching Relay is wired and operates the boiler.
• If using a single Switching Relay set to Master.
• When using multiple Switching Relays and/or Zone Valve
Controls, set one control to Master and set all other con-
trols to Member.
T-Stat 1 Priority DIP Switch
When T-Stat 1 is calling for heat by closing the R and W
terminals:
• 115 V (ac) is applied to the zone 1 circulator pump.
• Zone 1 indicator LED is turned on.
• Priority indicator LED is turned on.
• Zones 2 to 6 circulator pumps and LEDs are turned off.
• Expansion Member controls shut off their zones.
• After 60 minutes of continuous zone 1 call for DHW heating,
zones 2 to 6 and all Expansion Member control zones are
able to turn back on. This prevents building freeze up if the
DHW tank aquastat fails in the closed position.
Exercising DIP Switch
ON: Each circulator pump is energized for 30 seconds every
72 hours.
OFF: Circulator pump exercising disabled.
Post Purge DIP Switch
ON: After the last thermostat stops calling for heat, the last
circulator pump remains on for 2 minutes to purge heat from
the boiler to the zone.
OFF: Post purge disabled.
Mod Boiler DIP Switch
Select either 0-10 V (dc) or 4-20 mA signal to the modulating
condensing boiler. Consult the boiler manual to determine
the signal type. The DIP switch position does not matter if
the modulating boiler output is not used.
Fuses
• All fuses are T5A 250V slow blow.
• Fuses 1 to 4 correspond to the zone 1 to 4 circulator pump
output. If a fuse is blown, first check that the pump is not
seized and the wiring is not shorted. Then replace the fuse.
• Fuse 7 and 8 correspond to the 24 V (ac) transformer power
supply. If a fuse is blown, first check that the thermostat
wiring is not shorted. Then replace the fuse.
Expansion Terminals
Connect the five wires of the expansion bus from the master
to the member controls.
Terminal Description
A/tN4
Away signal connecting tekmar thermostats
B
RoomResponse
TM
signal from member controls
C
Power common
D
Demand signal. 0 Vdc = demand. 2 Vdc = no demand
E
Priority signal. 0 Vdc = priority. 2 Vdc = no priority
Power
• On when 115 V (ac) is applied.
• Off when power disconnected or transformer fuse is blown.
Priority
• On when zone 1 has priority over zones 2 to 4.
RoomResponse
TM
• On when modulating condensing boiler is operating below
maximum setting.
Zone 1
• On when thermostat 1 calls for heat.
Zones 2 to 4
• On when the corresponding thermostat calls for heat.
• Off during priority operation.
• Off when corresponding thermostat stops calling for heat.
