Economizers

Ken D.

Carol, Can you give a thumbnail description on troubleshooting Honeywell economizers? Thanks, so much.

DanHolohan

Carol

is on vacation this week, Ken.

Empire_2

Ken

Since Honeywell makes a number of different models, which ones are you inquiring about?

Mike T.

Ken D.

Thanks Dan.

Ken D.

Mike

Any and all. Or at least a general overview.

Empire_2

I didn't forget you Ken.

I am looking for my manual and trouble shooting guide all the way up to 2001,..Mainly for Carrier equipment, but a lot of equipment uses the HW actuators.......

Mike T.

Ken D.

Thank you.

Darin(in Michigan)

Economizers(from a rookie's standpoint)

Darin(in Michigan)

Economizers(from a rookie's standpoint)

I have found it helpful to remember that economizers use a motor that opens and closes based on resistances that change with temperature. The motors often have potentiometers internally that are attatched to the sweeping arm. The motor is constantly striving for resistance equilibrium. Visualize a switch in the return airflow that has three terminals like a three wire thermostat. Instead of the switch making contact from common to one of the other two, lets say the resistance between common(r) and W decreases if the resistance between r and B increases and vice versa. The motor "feels" the changes in resistances across R-W & R-B and seeks to get resistance equilibrium by opening and closing. Internally, the potentiometer adjusts and the circuits become equal and the motor stops. If R-W becomes less than R-B, the motor swings the other way. The amount the motor moves is determined by the adjustable potentiometer in the duct stream(not to be confused with the one inside the motor). The one inside the motor is to react to a change. The potentiometer in the duct stream initiates that change by changing resistance based on temperature(and can be tested with an ohm meter).

There is usually a switch on the external hood that makes the determination of whether or not there is enough cooling outside the building to even allow the damper to function. If there is not enough "free cooling" available, the y1 signal is pushed on to the contactor and the compressor is energized. However, if the temperature and humidity both are favorable to free cooling, the compressor is left off, power goes to your economizer control. The EC will allow the duct mounted potentiometer to take control. Now your duct mounted potentiometer will open and close the dampers to reach a good temperature going back into the space(55 degrees for example).

There are so many different variations of these but I hope this helps. If any of this is making sense let me know, otherwise I'll let the pros explain it.

Oh, by the way, NEVER jumper any of the terminals on the motor. Odds are they won't work anymore afterwards. My 2c.

Brad White_9

How can one possibly

beat that explanation? Good job, Darin.

I was going to jump in but your explanation has far more detail than my more general response would have; more to the questioner's point.

Brad

Empire_2

Yes very nice explanation.

Keep in mind the remote minimum position potentiometer can be located anywhere. Here is some literature that may help.

Mike T.

Ken D.

Darin

Thank you. Very helpful.