the 65 degree question can someone supply some good solid literature on why you should'nt run the AC when temps are too low? looking to have ammo when i'm confronted. opinions and/or personal practices also welcome. Re: the 65 degree question I believe it is HeatPumps that shouldn't be tested in cooling mode under 65 AC's are not tested under 60 (some HI make a practice not to test if the temp has dropped below 60 (for an extended period of time) in the last 24 hours or if the unit has not been energized for the past 24 hours). The best argument would be your SOP and the fact that most Inspection (Orgs and State) SOP's recognize the possibility of damage to a AC unit if operated when conditions are not conducive to testing. I.E.= Industry standard argument Don't have any literature but have a head full experience. The proper term is called (liquid migration) which occurs during the off cycle of the unit. Liquid freon will seek the coldest area of an enclosed system between the furnace A-coil and the outside condensing unit.

When outside ambients are below 60 degrees the MFG recommends not to operate these units because the coldest area of the system will be the outside unit and if liquid freon is lying in the compressor you can can damage the valves in the compressor when you start it up. Freon is simply stated, all about pressure temperature relationship if the home or the area of the furnace A-coil is in a warmer area than the condensing unit the freon will migrate toward the coldest area in a shut down mode. Once the compressor is actually started and operated in a normal mode no damage will occur to the compressore the damage will occur on the initial starting of the unit. If the outside unit is equipped with a crankcase heater the possibility of liquid migration is almost nil as the heat will drive the liquid freon from the crankcase If this sounds like Greek I can try another approach. Learn something new everyday! It may only be semantics but a liquid cannot be compressed.

doesnt sound greek to me. you mention the MFG states no running the unit under 60 degrees. All or most MFG's? crankcase heater...how would i know if a unit has one? newer technology or older one? now the big question...what's everyone's threshold on not running ac units due to outside temps? I think you will find that all MFG recommend not to operate at below 60 degrees this can vary within different SOP's per your State. My SOP states 60 degrees. Generally speaking if the outside ambient is below 60 degrees you will be getting squirrelly temps on the unit anyway won't tell you much of any thing other than it starts. Crankcase heater have been around since Mobey Dick was a Minnow Two kinds the stainless steel band around the bottom of the compressor with two wires going back to the top side of the contactor as this heater requires 220-volts when the unit is shut down. The second kind is embedded within the crankcase of the compressor and all you will see are two wires that appear to disappear into the metal housing of the compressor at the bottom.

Both kinds of heaters will be activated in the off cycle of the unit. I beg to disagree what do you suppose a water pump does when it increases the pressure from say 25 PSIG to 150 PSIG it compresses the liquid?????? If the temperature is as you stated I would think the unit breaking down at startup would fall under failed under testing. If a garage door comes off the track when you open it are you responsible for fixing it?window ac units sizing I never check the units if the outside temperature has been under 60% within a 24 hour period.buy used ac units StepByStep Home Services LCcheap small ac unit Providing Home Inspection Services to Southeast Michigan ITA Trained and Certified Matt that is just fine you made the decision to choose 65 degrees just stick with it.

I personally have operated in my other life units that were serving commercial areas with no windows that had high sources of heat generated from within the building and A/C units were operated 365 starting and stopping with an outside ambient at zero some with crankcase heaters some without. There is no rule that says Puff the magic dragon the valves will blow if you start this unit in temps below 60 or 65 as an HI pick a temp and just stay with it. Vince thats fine if you made this decision but can you explain why you choose those numbers. What's with the "24 hour period"? That sure would preclude everyone in the desert mountains between, say, here and El Paso from using their cooling systems since it regularly gets down to 40� at night and up to 90� during the day. If I had those inspection protocols, I would never be able to test the cooling systems here. Hmmmmmm. Certainly would make the inspection go faster. House Key News Getting your past Clients to work as hard for you as you worked for them.

NACHI 2005 U.S. Member of the YearWarm weather is on its way, which means that air conditioning units are firing up. However, there are some days when the temperature actually drops to a pleasant level. Here’s how to make your Nest Thermostat automatically shut off whenever the outside temperature gets cooler. Using a neat online service called IFTTT, you can tell your Nest Thermostat to automatically turn off if the weather ever reaches a specific temperature, that way you can open windows and save money by not running your AC when you don’t need to. For example, if the outside temperature reaches 73 degrees (which is good enough for opening windows and cooling your house), but the inside of your house is still pretty hot and the AC is still cranking, this is where something like this would come in handy. You don’t need the AC on when the weather is that nice outside, so being able to automatically turn off your thermostat when the weather gets cool can not only save you money, but can also be a great convenience to have.

If you haven’t used IFTTT before, check out our guide to getting started for info on how to create an account and connect apps. Then, come back here to create your Nest Thermostat IFTTT recipe. For your convenience, we’ve created the recipe in its entirety and embedded it here–so if you’re already well versed in IFTTT, just click the “Add” button below and off you go. You’ll need to connect the Weather channel and the Nest Thermostat channel if they aren’t already. If you want to customize the recipe, here’s how we created it. Start by heading to IFTTT’s home page and click “My Recipes” at the top of the page. Next, click on “Create a Recipe”. Click on “this” highlighted in blue. Type “Weather” in the search box or find it in the grid of products and services below that. Click on it when you find it. After you connect the Weather channel and get to the “Create a Trigger” page, select “Current temperature drops below” from the options.

Enter in the outside temperature that you want it to be in order for your Nest Thermostat to turn off and then click “Create Trigger”. Next, click on “that” highlighted in blue to set up the action that happens whenever the trigger fires. Type “Nest Thermostat” in the search box or find it in the grid of products and services below that. After you connect the Nest Thermostat channel and get to the “Create an Action” page, click on “Set temperature”. Since IFTTT can’t turn off your Nest Thermostat, you’ll simply be setting the thermostat to a higher setting so that the AC turns off. On the next screen, select your Nest Thermostat under “Which device?” and enter in the temperature that you want to set your Nest Thermostat to. Something high like 80 degrees should be fine. Click on “Create Action” to continue. Give the recipe a custom name if you want and then click on “Create Recipe”. From now on, whenever the weather outside drops below the temperature you specified in the recipe, your Nest Thermostat will be set to a higher setting, thus the AC will turn off and you can open windows.