heat pump freezing

[fliks]

I don't think my posts count are up enough for the pro forum so I hope I am not being out of line here.The property I work at has several 4 ton heat pumps, three of which run in cooling mode even when it is cold outside.These are in the fitness area and they want the area to stay at least 65.At times it has been 40 outside causing them to freeze up.What is the best solution for this issue. I think they make a pressure switch and possibly a t-stat but wanted to make sure it doesn't interfere with heating mode.Oh these are Goodman units that are about 2 years old. Thanks

[pauls heating &]

install low ambient controls

[beenthere]

You have enough post to apply for pro membership.

Might want to install an economizer, and use free cooling, instead of mechanical cooling.

[hvacvegas]

I agree with beenthere. I'm not a big fan of low ambient fan controls. The best thing is an economizer, but a low ambient fan control will work in a stich.

[fliks]

I just applied for pro membership.I am not familiar with an economizer.Could you tell me a little more about this system.Thanks again, I have been visiting this site for awhile now and learning.

[VTP99]

Is this a RTU or a split system ?

[CynicX]

I just applied for pro membership.I am not familiar with an economizer.Could you tell me a little more about this system.Thanks again, I have been visiting this site for awhile now and learning.

Its a device that on a call for cooling will look at the outside air temp, if its cool enough it will bring in outside air. Like opening a window.

The alternative is a low ambient kit. It will maintain the head pressure by cycling the outdoor fan on and off. Then your pressures wont get low enough to freeze.

Not a good idea running A/C in the winter time without the appropriate equipment to do such...

[udarrell]

Also, especially during cold weather operation, make sure the compressor crankcase heat is working, or you may lose the compressor!

[Kevin O'Neill]

An expansion valve on the indoor coil will often allow cooling operation down to 45 degrees outside without freezing the indoor coil. Also make sure you have enough air flow. Did you check your static at the blower?

[fliks]

It got to 65 degrees yesterday so I checked the charge in the units and found them to be a little low. These are 410 split systems on a 5 story building.About half the condensers are on the roof and the airhandlers are in the center of the room with metal spiral supplies.The static pressures are very low.It's a loft style property.I feel the supply openings are too large.They are about 20 feet up and offer alot of volume but not near enough velocity to throw the air down stairs.Also no ceiling fans so the up stairs is very hot/cold depending on what is on.Anyway back to the freezing issue, it sounds like the best solution for this situation would be the low ambient controls.I did research the economizer systems.I really like the idea but have no way to run ducts. Thanks for your help.

[VTP99]

Fliks--- look at Ranco fan cycling control #0102054

[just_opinion]

On the originl post you stated that they are heat pump. So put in a fan pressure control is a little tricky. Best that you consult with a knowlegeable tech in your company so you will learn something on the field.