I'll be installing a motor operated mixing valve by Johnson Controls after the heating season. I have a Honeywell controller: http://s3.supplyhouse.com/manuals/1351176224256/85587_PROD_FILE.pdf . I have no idea what the settings should be. With the several variables, trial and error could take a long time.
The controller has settings for Setpoint, Throttling Range, Integral and Derivative. It says not to use the derivative if possible and to use a wider throttling range with the integral function doing most of the work. Default values are 20F for throttling range, 400 seconds for integral, and 0 for derivative. These settings may have an air handling slant to them, however-I have no idea.
Where do I start?
This is what is says in the installation manual:
NOTES:
1. The Integral time is factory set for 400
seconds. This is a good middle range and
should satisfy many applications. The integral
time can be increased for applications where
sensed response is slow, and can be
decreased for applications where sensed
response is fast (e.g. discharge air control).
2. As a starting point, an optimal integral time for
discharge air typically ranges from 12 to 200
seconds. An optimal integral time for room
control typically ranges from 60 to 2,500
seconds. The purpose of integral action is to
reduce or eliminate the offset from setpoint
during steady state control that is often seen
in proportional only control.
3. Keep in mind that control is most sensitive to
throttling range. Adjust the throttling range
first before any adjustment to integral time.
Adjust throttling range to be as wide as
possible to start since this will provide the
most stable control. Remember that the
integral will eliminate the steady state error so
you do not need to have a small throttling
range to have accurate control. (Integral
action allows for controlling to a setpoint even
with a wide throttling range).
The controller has settings for Setpoint, Throttling Range, Integral and Derivative. It says not to use the derivative if possible and to use a wider throttling range with the integral function doing most of the work. Default values are 20F for throttling range, 400 seconds for integral, and 0 for derivative. These settings may have an air handling slant to them, however-I have no idea.
Where do I start?
This is what is says in the installation manual:
NOTES:
1. The Integral time is factory set for 400
seconds. This is a good middle range and
should satisfy many applications. The integral
time can be increased for applications where
sensed response is slow, and can be
decreased for applications where sensed
response is fast (e.g. discharge air control).
2. As a starting point, an optimal integral time for
discharge air typically ranges from 12 to 200
seconds. An optimal integral time for room
control typically ranges from 60 to 2,500
seconds. The purpose of integral action is to
reduce or eliminate the offset from setpoint
during steady state control that is often seen
in proportional only control.
3. Keep in mind that control is most sensitive to
throttling range. Adjust the throttling range
first before any adjustment to integral time.
Adjust throttling range to be as wide as
possible to start since this will provide the
most stable control. Remember that the
integral will eliminate the steady state error so
you do not need to have a small throttling
range to have accurate control. (Integral
action allows for controlling to a setpoint even
with a wide throttling range).
Last edited:
