Technical Data; Tekmarnet ® 4 Thermostat - Tekmar tN4 538 Wiring Brochure

Testing the tN4 Buses
The symbol is shown on the display when communication
is present. If the thermostat is connected in a network and
the communication is missing, there may be an open or
short circuit on the tN4 and C bus wires.
1. Remove the front cover from the thermostat.
2. To test for short circuits:
• Disconnect the tN4 bus wires on one end.
• Install wire nuts on each wire to ensure the wire ends
are not touching.
• Disconnect the tN4 bus wires on the other end.
• Measure for continuity using an electrical meter.
• If continuity is present, there is a short circuit fault along
the wires. It is recommended to replace the tN4 bus
wires.

Technical Data:

Technical Data
tekmarNet ® 4 Thermostat 538: One Stage Heat
Control
Packaged weight
Enclosure
Dimensions
Approvals
Ambient conditions
Power supply
W Relay
Sensors:
– Included
– Optional
The installer must ensure that this control and its wiring are isolated and / or shielded from strong sources of electromag-
netic noise. Conversely, this Class B digital apparatus complies with Part 15 of the FCC Rules and meets all requirements
of the Canadian Interference-Causing Equipment Regulations. However, if this control does cause harmful interference to
radio or television reception, which is determined by turning the control off and on, the user is encouraged to try to correct
the interference by re-orientating or relocating the receiving antenna, relocating the receiver with respect to this control,
and / or connecting the control to a different circuit from that to which the receiver is connected.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada.
tekmar Control Systems Ltd., Canada
tekmar Control Systems, Inc., U.S.A.
Head Office: 5100 Silver Star Road
Vernon, B.C. Canada V1B 3K4
(250) 545-7749 Fax. (250) 545-0650
Web Site: www.tekmarcontrols.com
Product design, software and literature are Copyright © 2008 by:
tekmar Control Systems Ltd. and tekmar Control Systems, Inc.
Microprocessor PID control; This is not a safety (limit) control
0.8 lb. (380 g)
White PVC plastic
2-7/8" H x 2-7/8" W x 13/16" D (73 x 73 x 21 mm)
CSA C US, CSA/UL 61010-1, meets Class B: ICES and FCC Part 15
Indoor use only, 36 to 122°F (2 to 50°C)
RH max 92% to 104°F (40°C), and 50% above 104°F (40°C)
Altitude <9840 feet (3000 m), Installation Category II, Pollution Degree 2
24 V (ac) ± 10% 50/60 Hz, 1.8 VA Standby, 56 VA fully loaded, NEC / CEC Class 2
24 V (ac) 2 A
NTC thermistor, 10 kΩ @ 77°F (25°C ± 0.2°C) ß = 3892
None
tekmar type # 071, 070, 072, 073, 076, 077, 078, 079, 083, 084
8 of 8
3. To test for open circuits:
• • Disconnect the tN4 bus wires on one end and connect
them together.
• • Disconnect the tN4 bus wires on the other end.
• • Use an electrical meter to measure for continuity.
• • If there is no continuity, there is an open circuit fault
along the wires. It is recommended to replace the tN4
bus wires.
All specifications are subject to change without notice.
Printed in Canada. W 538 - 12/08.