tekmar 552 Thermostat Installation User Manual

Page 9

552_D - 09/14

9 of 44

A Watts Water Technologies Company

Testing the Power

1. Remove the front cover from the thermostat.
2. Use an electrical test meter to measure (ac) voltage between the R and C terminals.

The reading should be 24 V (ac) +/– 10%.

3. Install the front cover.

Testing the Heat Relay

1. Remove the front cover from the thermostat.
2. Touch the

button and set the heating temperature below the current room

temperature. There should be no “Heat On” symbol on the display.

3. Set the electrical test meter to continuity.
4. Place electrical meter probes between R and W. There should be no continuity. If

there is continuity then there may be a wiring fault or the relay may be faulty.

5. Touch the button and set the heating temperature above the current room

temperature. Make sure the display does not show “WWSD”. The “Heat On” symbol
should appear on the display.

6. There should now be continuity between the R and W terminals.

Testing the tekmarNet

4 Bus Wiring

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.

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.

•
•
•
•
•

•
•
•
•

Testing tekmarNet

4 and Stand Alone Wiring

---------------------------