tekmar 542 Thermostat Installation - Manual (Page 24)

© 2007 D 542 - 08/07 24 of 28
tN4 Address Section Q
When connected to other tN4 devices through a tN4 bus,
the thermostat is automatically assigned a network address.
The tN4 address is useful when trying to correct bus error
open and short circuits.
The address includes the bus water temperature designation
and a device number. The bus water temperature designations
available are Boiler, Mix 1, Mix 2, etc. The device number
can range from 1 to 24. If the thermostat is operating as a
member of a thermostat-only network, the thermostat does
not have an address and the address item in the MISC
menu is not available.
The device number determines the heating priority for each
zone. A thermostat with device number 1 has a higher priority than device number 24. The tN4 address allows the tN4
system control to shut off low priority zonezs when the heat
source is unable to heat all zones simultaneously. In some
cases, the installer may want to change the thermostat’s
address in order to change the thermostat’s priority relative
to other thermostats.
Note: Keep track of manually set tN4 addresses. When
a tN4 address is manually set, tN4 thermostats using the
Auto Address setting will automatically be assigned new
addresses.
If two thermostats are manually set to the same address, an
error message will appear. The error remains until one of
the addresses is manually changed to a vacant address
Pump Exercising Section R
When connected to a tN4 system control, the thermostat
exercises the pump relays for 10 seconds every 3 days.
Exercising helps prevent pump seizure. While the thermostat
is exercising, the display shows “Test”. Exercising does not occur when:
•
• Mode of Operation is set to Off.
•
• Heat Source is set to Other.
•
• DIP switch 2 is set to None.
Error Messages
Local Errors and Device Errors
Error messages are used to indicate a problem somewhere in the system. There are two types of error messages: Local
Errors and Device Errors.
A Local Error indicates an error specific to a device. For example, a thermostat with a sensor short circuit will show a Sensor
Short Error on its display. No other devices will show this specific error (unless they also have a sensor short circuit).
A Device Error is used to indicate that there is a local error somewhere else on the system. For example, if a thermostat has
a sensor short circuit, that thermostat will show a Local Error indicating specifically what the problem is. All other devices on
the network will show Device Errors, indicating the address of the device with the Local Error. In other words, Device Errors
are nothing more than pointers, showing you that there is a local error somewhere on the system and where to find it.
Error Priority
Only one error can be shown on a particular device at a time. If there is more than one error on the system, the highest
priority error will be the one that is shown. The table on pages 19 and 20 lists error messages in order of high priority to
low priority.
How to Locate an Error Message
If the warning symbol (flashing circle with exclamation mark) is visible on screen, this indicates that there is an error
somewhere on the system. To view the error message, you must first put the control into the Advanced or Installer access
level (available in MISC menu). When an error message is present, it is available as an item in the VIEW menu.
While in the View Menu, press the item button until the error message is displayed. You may have to advance through
several View Menu items before the message is displayed.
If the error message is a Device Error (if “DEV” or “DEV ERR” is shown on screen), read the address shown and go to the
device with that address. That device will have a Local Error indicating specifically what the problem is. When the problem
is corrected, the error message will automatically clear.