We regularly set parameters on the programmable thermostats we install. We sell air conditioners and furnaces, not freezers and ovens. Operating standard home comfort system equipment way outside the actual intended design criteria is just asking for problems. Can't think of any manufacturer who would actually even suggest that 55 degrees for residential cooling equipment is reasonable.

 

They must of have thought the homeowner meant outside ambient limit being 55 degrees.

 

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Mahlv, This is the AOP forum and you need the * along with professional membership in order to reply to questions in this forum. Refer to the links in my signature for further information.

 

Chris, my GMC won't do but 100 mph and the motor shuts down, is this fair for GM to do this? I personally don't think so, but I just write it off as they do it for some reason, safety, or maybe to keep the motor from blowing up, sometimes folks look at what they are doing as a thing that is supposed to help/benefit us. Just because they did what they did, don't mean they were wrong, it's just part of their whole package, but IMO they should have let you know up front, because in my world in Houston this is not the norm, but then again I don't condemn it.

 

American Standard/Trane say minimum outdoor temp running their A/Cs without evap defrost stat or low ambient kit is 55. Others want higher. Rheem says don't run below 70 without fan cycle kit which is a bit extreme.

 

Your installing dealer had actually did you a favor by setting the indoor temperature low limit at 67 degrees. Low ambient temperatures indoors without protection to prevent the coil from freezing and no superheat to protect the compressor from damage can be costly to repair to say the least.

The 55 degrees that tech support was referring to was the lowest outdoor temperature that the system from the factory can operate at without additional protection added.

 

Thanks for all your replies. I feel better now... the lowest I ever run the AC is 65. Do you think that's a safe temperature to run?

 

the lowest I ever run the AC is 65. Do you think that's a safe temperature to run?

O yea that's safe, especially if you have a hot GF or Wife, sometimes we need to. :grin2:

 

I read it wrong, indoor temp limit 67. Much colder you'll freeze her up. You may get by with 65 depending upon airflow. We started installing a stat with limits. I've set the cooling at 65 before to protect the equipment from tampering fingers like kids. Or people that think setting it to 60 will cool the house faster.

 

I read it wrong, indoor temp limit 67. Much colder you'll freeze her up. You may get by with 65 depending upon airflow. We started installing a stat with limits. I've set the cooling at 65 before to protect the equipment from tampering fingers like kids. Or people that think setting it to 60 will cool the house faster.

So true.
ayattention:

 

if you set the thermostat at 60 and the unit freezes up then when the contractor comes and thaws it out I'll bet you get mad when he hands you a bill . I set the thermostat at 65 for cooling and 80 for heat never had a complaint

 

Most folks don't set the stat that low so I wouldn't hold it against the installer. Hell, my wife sets it at 69° every nite and I'm wantin to wack her.

 

dont know if Ive got an * yet but i want to respond

 

I doubt your unit was designed to cool your house to 55 degreesas it would be grossly oversized at 72 degrees indoor temp. I set limits in the stats when I install them to help prevent nuisance calls like freezing up or to hot calls normally 64 cooling and 80 heat and unless you have some kind of special unit with head pressure control and defrost for indoor unit you can and will cause damage to the system.so there is nothing wrong with them setting limits however they should have left operators manual for stat

 

hvac wiz 79,

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