tekmar 422 Universal Reset Module User Manual
Page 3
3 of 32
© 2007
D 422 - 08/07
Access Level
tN4 Boiler / Mix 2
Use the tN4 Boiler / Mix 2 DIP switch to select whether
the second tN4 bus (terminals 59-60) is to operate as
a boiler water temperature or as a second mixing water
temperature.
•
• If set to Boiler, this creates a system with one boiler and
one mix water temperature.
•
• If set to Mix 2, this creates a system with two mix water
temperatures. If Mix 2 is selected, a mixing expansion
module must be connected to the Boiler / Mix 2 bus.
Boiler Sup / Ret
Use the Boiler Sensor Supply / Return DIP switch to select
the location of the boiler sensor.
•
• If the boiler sensor is located on the supply, this DIP
switch should be set to Sup. The 422 is the control that
determines the boiler water temperature. Set the boiler’s
aquastat at least 20°F (11.0°C) higher than the Boiler
Maximum setting.
•
• If the 422 provides a heat demand to an external boiler
control, this DIP switch must be set to Ret. Install the
boiler sensor on the return side of the boiler loop.
The boiler’s operating temperature is controlled by its
aquastat, or an external boiler reset control.
Boil On-Off / Mod
The Boil On-Off / Mod DIP switch selects whether the
control operates an On-Off boiler or the firing rate of a
Modulating boiler.
•
• If set to Boil On-Off, the control operates an On-Off
boiler.
•
• If set to Mod, the control operates a Modulating boiler.
Off / Flushing
The Off / Flushing DIP switch selects whether the control
operates a Flushing feature. Heating systems that use
potable water require periodic flushing to prevent the water
from stagnating.
The flushing operation occurs if any zone has not operated
for 7 days. All zones, mixing device(s), and applicable
system pumps are turned on for 4 minutes.
•
• To activate the Flushing feature, set to Flushing.
•
• To deactivate the Flushing feature, set to Off.
tekmar Stager / Off
Use the tekmar Stager / Off DIP switch when a tekmar
staging control is be connected to the 422 in order to
operate multiple boilers. A tekmar stager may include Boiler
Controls 264, 265, and 268.
•
• If a tekmar Stager is installed, set to tekmar Stager. The
422 will then provide the stager with a target temperature
via a 0-10 V (dc) signal. When the tekmar Stager / Off
DIP switch is set to tekmar Stager, the Boiler Sensor
DIP switch must be set to Sup.
•
• If a tekmar Stager is not installed, set to Off.
The Access Level restricts the number of Menus, Items,
and Adjustments that can be accessed by the user. The
Access Level setting is found in the Miscellaneous (MISC)
menu. Select the appropriate access level for the people
who work with the control on a regular basis.
There are two Access Level settings:
•
• Installer (InS): This is the factory default setting. This
access level is sufficient for the normal set up of the
control.
•
• Advanced (Ad): All of the control settings are available
to the user.
In the following menu tables, the access level the item is
visible in is shown in the access column.