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© 2010 D 270 - 08/10
DHW MODE 4 OPERATION
In DHW MODE 4, the space heating zones must be prevented from coming on during DHW demands using external wiring. This
can be done using an external relay to remove power from zone pumps or zone valves while a DHW Demand is present. This
external relay is interlocked with the
DHW Pmp / Vlv
contact.
During a DHW Demand, the control closes the primary pump (
Prim
P1
) contact and the
DHW Pmp / Vlv
contact. Once the DHW
Demand is removed, or during a DHW priority override, the
DHW Pmp / Vlv
contact is opened, and the external wiring should allow
the space heating zones to operate.
There is no mixing purge available in DHW MODE 4. After DHW priority, the boiler supply water temperature may exceed the design
water temperature of the space heating system and can result in damage to the heating system.
Installation
CAUTION
Improper installation and operation of this control could result in damage to the equipment and possibly even personal injury. It is
your responsibility to ensure that this control is safely installed according to all applicable codes and standards. This electronic
control is not intended for uses as a primary limit control. Other controls that are intended and certified as safety limits must be
placed into the control circuit. Do not open the control. Refer to qualified personnel for servicing. Opening voids warranty and could
result in damage to the equipment and possibly even personal injury.
STEP ONE
GETTING READY
Check the contents of this package. If any of the contents listed are missing or damaged, please contact your wholesaler or tekmar
sales representative for assistance.
Type 270 includes: One Boiler Control 270, One Outdoor Sensor 070, One Universal Sensor 082, Data Brochures D 270, D 070,
D 001, Application Brochure A 270.
Note:
Carefully read the details of the Sequence of Operation to ensure that you have chosen the proper control for your application.
STEP TWO
MOUNTING THE BASE
Remove the control from its base by pressing down on the release clip in the wiring chamber and sliding the control away from it.
The base is then mounted in accordance with the instructions in the Data Brochure D 001.
STEP THREE
ROUGH-IN WIRING
All electrical wiring terminates in the control base wiring chamber. The base has standard
7 8
in (22 mm) knockouts, which accept
common wiring hardware and conduit fittings. Before removing the knockouts, check the wiring diagram and select those sections
of the chamber with common voltages. Do not allow the wiring to cross between sections, as the wires will interfere with safety
dividers which should be installed at a later time.
Power must not be applied to any of the wires during the rough-in wiring stage.
•
All wires are to be stripped to a length of
3 8
in (9 mm) to ensure proper connection to the control.
•
Install the Outdoor Sensor 070 according to the installation instructions in the Data Brochure D 070 and run the wiring back to
the
control.
•
Install the Boiler Supply Sensor 082 according to the installation instructions in the Data Brochure D 070 and run the wiring
back to the control.
•
If an Indoor Sensor 076 or 077 is used, install the indoor sensor according to the instructions in the Data Brochure D 074 and
run the wiring back to the control.
•
Run wire from other system components (pumps, boiler, etc.) to the control.
•
Run wires from the 115 V (ac) power to the control. Use a clean power source with a 15 A circuit to ensure proper operation.
Multi-strand 16 AWG wire is recommended for all 115 V (ac) wiring due to its superior flexibility and ease of installation into
the
terminals.