tekmar 265 Boiler Control - Manual (Page 18)

© 2010 D 265 - 07/10 18 of 36
Section G1: Pump Operation
PRIMARY PUMP OPERATION
The primary pump operates under the following conditions:
• A boiler demand is present and the control is not in Warm Weather Shut Down (WWSD).
• An external input signal is present.
• A DHW demand is present and DHW MODE is set to 3 or 4.
• A setpoint demand is present and Setpoint MODE is set to 3.
Primary Pump Purge
After all demands are removed, the control continues to operate the primary pump for a period of time. The maximum length of time
that the primary pump continues to run is adjustable using the Purge setting. The primary pump continues to run until either the
purging time has elapsed or the boiler supply temperature drops more than ½ of the differential below the boiler minimum setting.
Primary
Pump
Boiler
Pumps
Primary
Pump
Boiler
Pumps
Primary
Pump
Boiler
Pumps
OR
Example Range = 0 - 10 V (dc)
Input = 7 V (dc) 157°F (69°C)
Offset = +5°F (3°C) + 5°F (3°C)
Boiler Target = 162°F (72°C)
CONVERSION TABLE 0 - 10
0 - 20 mA* 0 - 10 V (dc) Boiler Target
0 0 – – – (OFF)
2 1 50°F (10°C)
4 2 68°F (20°C)
6 3 86°F (30°C)
8 4 103°F (39°C)
10 5 121°F (49°C)
12 6 139°F (59°C)
14 7 157°F (69°C)
16 8 174°F (79°C)
18 9 192°F (89°C
20 10 210°F (99°C)
*Requires 500 Ω Resistor in Parallel
*Requires 500 Ω Resistor in Parallel
CONVERSION TABLE 2 - 10
4 - 20 mA* 2 - 10 V (dc) Boiler Target
0 0 – – – (OFF)
4 2 50°F (10°C)
6 3 70°F (21°C)
8 4 90°F (32°C)
10 5 110°F (43°C)
12 6 130°F (54°C)
14 7 150°F (66°C)
16 8 170°F (77°C)
18 9 190°F (88°C)
20 10 210°F (99°C)
OFFSET
The Offset setting allows the boiler target temperature to be fine tuned to the external input signal. The control reads the external
input signal and converts this to a boiler target temperature. The Offset setting is then added to the boiler target temperature
Section G1
Pump
Operation
Section G: Pump Operation