tekmar 268 Boiler Control - Manual (Page 4)

© 2010 D 268 - 11/10 4 of 32
Section A
General
Operation
Page 4 - 6
Section B
Staging
Page 6 - 8
Section C
Pump
Operation
Page 8 - 9
Section D
Boiler Reset
(Stand Alone)
Page 9 - 11
POWERING UP THE CONTROL
When the control is powered up, all segments in the LCD are turned on for 2 seconds. Next, the control displays the control type
number in the LCD for 2 seconds. Next, the software version is displayed for 2 seconds. Finally, the control enters into the normal
operating mode.
OPERATION
The control operates up to nine on / off heat sources to control the supply water temperature to a hydronic system. The
supply water temperature is based on either the current outdoor temperature, an external 0 - 10 V (dc) or 2 - 10 V (dc) signal,
or a fixed setpoint.
Section F
Setpoint
Page 15 - 15
Decreasing Outdoor Temperature
Incr
easing W
a
ter T
e
mperatur
e Terminal Unit Terminal Unit
Indoor Design Indoor Design Outdoor Design Outdoor Design
Design Supply Design Supply
The following defined terms and symbols are used throughout this manual to bring attention to the presence of hazards of various risk
levels, or to important information concerning the life of the product.
INSTALLATION
CATEGORY II
- Warning Symbol: Indicates presence of hazards which can cause severe personal injury, death or
substantial property damage if ignored.
- Double insulated
- Local level, appliances
Definitions
Sequence Of Operation
Section A: General Operation
Section G
External
Input
Page 16 - 17
Section E
DHW
Page 12 - 14
Boiler Reset (Stand Alone)
When a boiler demand signal from the heating system is present, the control operates
the boiler(s) to maintain a supply temperature based on the outdoor air temperature and
Characterized Heating Curve settings.
Domestic Hot Water
When a DHW demand signal from a DHW aquastat is present, the control operates the
boiler(s) to maintain the supply water temperature at least as hot as the DHW XCHG
setting. Refer to section E.
Setpoint
When a setpoint demand signal from a setpoint system is present, the control operates
the boiler(s) to maintain the supply water temperature at least as hot as the SETP setting.
Refer to section F.
External Input 0 - 10 V (dc) or 2 - 10 V (dc)
When an external input signal is present, the control converts the signal to a target supply temperature. The control operates the
boiler(s) to maintain the required supply water temperature.