View Full Version : head pressure control

05-05-2007, 11:28 AM
could someone explain to me in lawmans terms re head pressure control in hvac systems re condensor

05-05-2007, 11:33 AM
Just click on the link on your post.

05-05-2007, 11:34 AM
where is the link,cannot see it bud

05-05-2007, 11:36 AM
found it thank you.any chance you could explain it better to me

05-05-2007, 03:52 PM
Hi scott12,

Head pressure control means you keep the condensing pressure high enough so the TEV can function properly, i.e. gives the design capacity.
When ambient temperature drops so would the condensing pressure therefore, the pressure drop across TEV will be lower than the design value.
When the pressure drop across TEV drops its capacity drops too.
I order to keep the condensing pressure up (when ambient temp is low) we have to turn the condenser fans off. Or use an inverter to reduce the fan speed.
Or other methods are available.

I hope you can see the problem.

The MG Pony
05-05-2007, 06:36 PM
To build on that The most efficient system is the inverter as it can dynamicly change the fans speed to one that is best apt for the situation.

US Iceman
06-05-2007, 12:27 AM
Fan speed control or fan cycling may not work very well if the winter temeprature gets too low. If you have to operate an air-cooled DX system at very low dry bulb temperatures, a flooded condenser is the only way to make it work properly.