Need to prevent compressor from running in winter

[DR21702]

I have installed a zoned HAVC system and have an a zone of my house that needs to get cold air during the winter because of heat caused by computer equipment. I have the HVAC controller setup to open an attic air intake damper for cold air during the winter instead of running the compressor when a zone calls for AC. The switchover is controlled by a home controller system PC so I'm paranoid about it as the software is still in development and there may be bugs.

What I need is a fool-proof safety mechanism to prevent the compressor for starting when the outside temperature is below 50F as the compressor will be covered in the winter to keep snow out.

I there a pre-build temperature sensor I can install that will accomplish this?

Dave

[16x80]

DR21702

Welcome to the Home Repair Forums

Can you come to my house and do that? My Comp room is 5-10 degrees hotter than the rest!

They make a low ambient control to run the ac in the winter but its designed that way I doubt you can change it! I was thinking you could just pull the disconnect from the outdoor unit or turn off the breaker for it in the winter, But you got it all fancy and stuff!

I would recommend an in line high voltage control that you can hook up to this software that would cut the power to the out door unit when the vent opens up in the winter! It would have to be rated at the max over current value that the out door unit would pull!

16x80

[DR21702]

I have a townhouse in Maryland with the humid hot east coast summers. I was having the problem of the top floor being a stuff 78-80 degrees from noon till 8PM. I also wanted to automatically switch heat/cool to deal with the fall/spring time when the heat may be needed at night the AC during the day.

I got a RCS ZC6R zone controller, the site is (www.resconsys.com), the best prices are at www.worthdist.com. To control the zones requires installation of motorized dampers such as the ones at EWC Controls (www.ewcontrols.com). I added wiring while the house was build so I already have HVAC wire (for the dampers which use 24VAC)and CAT5 for the thermostats. The funance unit is wired to the zone controller and the thermostats are replaced with wall display units wired to the zone controller. The dampers come in square and round styles. Round is easy to the install with the flexduct, for square dampers you have to order to the size of the duct and cut a side of the duct to slide it in.

A bypass damper is also required because the static pressure will get too high when most of the dampers are closed, you can dump the excess back into the return or some large space. Since I use AC most of the year I dumped my excess on the 3rd floor at the top of the stairwells as the cold air will move downward to the 1st/2nd floors and help keeps that cool.

The result of this was quite dramatic. With the cold air not being wasted on the lower floors when the reached the required temperature the air unit would cool the 3rd floor much better and the unit would not run as long saving power. Still I couldn't get the 3rd floor rooms to get below 75F so I added 8" duct fans into the main ducts to the rooms and added relays so that would only turn on when the duct was open. Now I can get 71-73F on the top floor easily without the compressor running endlessly for 8+ hours everyday.

Having never done an HVAC work I did alot of reading up on this and learning quite a bit doing this project.

All the parts for this costed about $1000, so the power savings alone over several years probably won't make up the cost of the system, so unless you have money to throw into it for the convienence or have rooms that can't be conditioned I wouldn't recommend this.