User manual

Chapter 4: Programming your SEC-HD Phason
32
How proportional control works (stage 5 only)
Proportional heating
When configured for proportional heating, the relay controls a pump or valve and operates as a
proportional cycle timer. Typical use for proportional heating is in-floor heating using water pipes,
which is often in livestock buildings.
The following example uses the default settings for Program A.
 Parameter 12, Stage 5 set point = 84.0°F
 Parameter 13, Stage 5 P-band temperature = 2.0°F
 Parameter 14, Stage 5 P-band interval = 10 minutes
10 minutes ÷ 2.0 = 5 minutes change per degree, therefore:
 At 84.0: 0.5 min on (this is the minimum time regardless of interval parameter), 9.5 min off
 At 83.5: 2.5 min on, 7.5 min off
 At 83.0: 5 min on, 5 min off
 At 82.5: 7.5 min on, 2.5 min off
 At 82.0: 10 min on, 0 min off (always on)
The minimum relay ON duration is 0.5 minutes.
When the temperature is above the set point (12) the water pump is off.
82.0°F
84.0°F
When the temperature is between the set point (12) and the proportional
band temperature, the water pump is on for a duration, and then off for a
duration.
When the temperature is below the set point (12), minus the proportional
band setting (13), the water pump is always on.