tekmar 557 Thermostat Installation - Manual (Page 6)

© 2014 557_D - 09/14
6 of 52 A Watts Water Technologies Company
Thermostat Wiring
The thermostat operates a single heating system zone and can be wired in three
different ways.
Stand Alone - Similar to tekmarNet
® 4 wiring with tN4 wiring terminal not used. First
stage heating relay (Rh1 - W1) can be wired directly to switching relays.
tekmarNet
® 4 - Allows the thermostat to be wired using 4 wires to a tN4 Wiring Center
or Zone Manager point-to-point. Alternatively, the thermostat can operate the heating
and cooling equipment locally and the tN4 communication bus can be daisey-chained
from one thermostat to another.
tekmarNet
® 2 - Allows the thermostat to be wired point-to-point using 2 wires to a tN2
Wiring Center, House Control, or Zone Manager. This allows easy wiring for retrofit
applications.
Application specific wiring diagrams are provided in the 557_A brochure.
Testing the Thermostat Wiring
Compatible Sensors
The thermostat is compatible with Indoor Sensor type 076, 077, 084, Slab Sensor
type 072, 073, 079, Outdoor Sensor type 070, Duct Sensor type 083 and Humidity &
Temperature Sensor type 086.
Only qualified personnel should perform testing procedures. A licensed electrician
is recommended.
Testing tekmarNet ® 2 Wiring ------------------------------------------ ------------------------------------------
Testing the Power
If the thermostat display turns on, this indicates that the thermostat is operating correctly
and there are no electrical issues. In the event that the display is off, or the display is
cycling on and off:
1. Remove the thermostat wiring cover.
2. Check to ensure that the tN2 wires on the thermostat are connected to a zone on a
House Control, Wiring Center, or Zone Manager.
3. Use an electrical meter to measure DC voltage between the tN2 terminals.
If the DC voltage is 0 V (dc) for at least 20 seconds, then there is an open or
short circuit in the tN2 wires.
If the DC voltage is 0 V (dc) for 10 seconds and then is 23 to 24 V (dc) for 5
seconds, this indicates the wiring is correct. •
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