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?ac unit brand names I never check the units if the outside temperature has been under 60% within a 24 hour period.inside wall ac cover StepByStep Home Services LCcar air conditioning cost to repair it 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 YearQuestion: In the process of selling my home, the buyers requested a home inspection. My problems started when the mold inspector reported elevated spores were four to five times the amount found outside. After paying a contractor to clean and treat for molds, the follow-up test showed the levels were even higher. The buyer refused to complete the deal. What made the mold grow so fast, and did we get ripped off by the contractor? Answer: With a little investigation, I was able to gain some additional information about the sale of your home. It seems that soon after the initial inspection, the home was left vacant with the utilities off. The resulting enclosed dark and damp environment created an almost perfect situation for mold spores to grow. In the summer, a closed house with the air-conditioning turned off will have higher humidity levels than an air-conditioned home. A vacant house also receives little or no sunlight through closed shades and no air movement with the fan off and the doors locked.

If you had simply left the air conditioning running, it would have cooled the home and removed moisture from the air and circulated and filtered the air. Molds thrive when the humidity levels exceed 70 percent. Because humidity levels vary from day to day, the thermostat should have been left at or below 74 degrees, and the fan should have been set to "On." Normally, mold cleaning and remediation processes disturb the spores, which become airborne and can settle on unclean or untreated surfaces, where they continue to thrive in the humid, warm, dark conditions. In my opinion, the remediation contractor failed you in that he did not warn you of the potential for recontamination. The Environmental Protection Agency suggests that self-cleaning should be considered if the area to be treated is less than 10 square feet. A guide to treatment and cleaning is available at http://www.epa.gov/mold/index.html. You can also learn more about mold remediation contractors and remedies for contaminated buildings.

An article by Dr. Ronald E. Gots that appeared in The Laker magazine underscores the myth surrounding phobias about molds and mold contamination. Basically, the article states that there are no scientific studies that show molds are unhealthy at typical indoor levels. Reactions to molds that have been documented are: allergic responses, minor irritant effects and infections in individuals with impaired immune systems. Molds present at typical indoor levels have never been scientifically shown to cause any other illness. Even when mold spores were at elevated levels, there were no similar elevated reports of illnesses. Examples from the article show certain occupations that are exposed to extremely high concentrations of mold spores. Sawmills: 1.5 million CFU/m3 (colony-forming units per cubic meter of air). Honeybee overwintering facilities: 2,200 to 13,931 CFU/m3 Spawning sheds of mushroom farms: 100,000 CFU/m3 Municipal waste-composting facility: 8.2 million CFU/m3

it's 10 times greater (1.2 billion CFU/m3) on farms where adverse health effects are reported. In these highly exposed populations, however, there are no reports of brain damage or of many of the other fungal diseases now common in current indoor mold attributions. What I gathered from the article is that some people -- those with asthma, hay fever or suppressed immune systems -- can be affected by low levels of mold spores, while the majority are not aware of the spores in the very air they breathe, even when there are elevated levels. When mold spores are discovered at elevated indoor levels, you need to contact your doctor first to determine if the mold species will affect you or your family. Then you need to consider some type of removal or treatment of the affected areas. If the buyer is worried about mold spores, he should check the home or apartment where he lives. I can guarantee that mold spores are present. Dwight Barnett is a certified master inspector with the American Society of Home Inspectors.