sammy

Can ICM325 be used to control head pressure if the system does not have a txv ? Why would this be if we are just slowing condenser fan motor during low ambient temperature ? Application is r22 2.5 ton split system with old Carrier air handler , has orifice. Any input would be great.

phbsales

I wouldn't do it.

You have more control using a low ambient kit that is based solely on pressure versus airflow.

Stick to the tried and true...........

sammy

Not sure what you mean by low ambient kit . If you talking about headmaster type pressure valve this cant be used as there is no receiver on the system. We do not want to use fan cycle switch as condenser fan cycles too rapidly and we we have too much pressure variations with this type of control.

mrtinker

I'm putting my $.02 worth now.... A solid state low ambient kit that modulates the RPM of the OFM by reacting to the temperature of the liquid line (sensor part of kit) should work just fine for this application.... About $150. (wholesale)

beenthere

Works a lot better if the sensor reacts to the compressor discharge vapor temp. The top 1/3 of the condenser coil is the recommended place to read it.
This area reflects the indoor load. And allows the control to have a tighter rain on the OFM's speed.

On fixed metering device systems. You can have a lot of flash gas, since its only feed control is by the pressure difference between the liquid line and the evap coil. You can often run less then 100 PSIG difference. And end up starving the coil, and freezing it up anyway.

If this is for a electronic or mechanical area. raise your indoor air flow also. It will also help keep the coil from freezing/frosting just before the control slows the blower on start up.

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