AIR CONDITIONING ?

[Switch Kit]

I know very little about how this works so I thought I might ask the great minds of this Forum. IM talking about central AC in the home , Does anybody know what the normal degree of cool air that would be blown out of the system if it were working properly ?

Thermostat ? When this is set does it change the degree of cool air that will be blown out at any given time or does the cool air remain the same at any setting on the thermostat ?

My AC is about 14 years old , within that time it has been used very sparingly , so it really hasn't had alot of use in these years. IM basically questioning the thermostat at this time . I keep my house in 100 degree weather at about 80 degress , for the thermostat to work I must set it at 86 degrees for it to turn on and off and keep the place at about 80. Does this sound right ?

I also have a older mercury type thermostat , would it do me any better to change it to a digital type ? although I really wouldn't know why I would want to do that ? Any help on my questions would be appreciated. Thanks.

 

[BOOTY MONSTER]

how does central air conditioning work - Google Search

 

[Wire Weasel]

Hey SK, I can help. Used to be...guess I still am, A residential HVAC service tech, just not doing that for a living anymore.

The temp of the air coming out of the supply vents should be 20-25 degrees cooler than the room air.

Yes the AC is a "single speed" cooling mechanism. It does not put out colder air if you turn the temp down....it only runs longer.

Sounds like your thermostat is out of calibration. Your mercury switch tstat is a proven, time tested device and there are billions in use. Right behind that metal coil that the mercury bulb is attached to is a small nut. They make a special skinny wrench to reach it for turning. If you can come up with a skinny wrench that fits that nut....then hold the temp setting lever still and turn the nut....sounds like to the left, a little bit. Walk away for 15 minutes and then recheck the operation. Repeat procedure until the operation matches the desired temp.

Also...are you sure the room temp IS what the tstat thermometer is saying? 'Cause those are very cheap little thermometers that they built into tstat covers. Check the room temp first with a known good thermometer. Any stem type thermometer or one with a probe can be tested by placing in a glass of ice water. Should read about 33 degrees.

Good luck

 

[Switch Kit]

Excellent WW ! Thank you for your time. Booty ? The links are a plenty , they still didn't answer my questions. (Had been there none that many times before) thank you all the same.

I put a meat thermometer in one of the vents and it read about 68 degrees of cool air blowing out. You nailed it about the (Right behind that metal coil that the mercury bulb is attached to is a small nut) You obviously know your mercury switches WW.

IM glad to hear you say that ( Your mercury switch tstat is a proven, time tested device and there are billions in use.) I think your right about the calobration , makes sence in my case . I may just leave it be and set it where it keeps my place at 80 as I have been.

I may want to play tech and get a nice digital one to install ? other then that I will leave well enough alone , other then to change the filters when need be. This is a OK model I suppose , back 14 years ago you could conceder this a middle of the road unit in cost , not the best but not the cheapest either. Thanks again for your input WW.

 

[555]

well let me ask this question

by adding a mister or a small sprinkler so that the water will hit the coils
and cool it off
anyone try this

 

[Sickpuppy22]

Another thing you could do is ask a hvac guy to check if the freon either R22 r134 depending on what the unit uses. sometimes on older machines over time can lose small amounts of gas.

Also you could go and clean the heat exchanger coil thoroughly if its blocked with dust dirt grime it wont exchange heat properly and wont produce colder air.

Nu- Clagon makes all sorts of cleaners for Coil indoor and outdoor you name it they made it lol.

Might also want to upgrade thermostat but i recommend you get a service call if none of the posted helped resolve the problem.

One last thing to check is the compressor is it Icing up when it is operating durring long periods of time?

 

[Wire Weasel]

well let me ask this question

by adding a mister or a small sprinkler so that the water will hit the coils
and cool it off
anyone try this

Hey Triple Nickle,

Man I've actually done that a time or two back in the day. It's not necessary in today's units as they've increased the efficiency greatly and this type of additional condenser cooling wouldn't be any benefit. Rheem used to make a water cooled condensing unit but they were junky and maintenance nightmares...they didn't last very long.

It would benefit the lowest of the low-efficiency units from the 60's and 70's but there probably aren't many of those units still in service anymore.

The key is to use small misting nozzels like are used with mist type humidifiers. This way only the minimal amount of water is used with no excess runoff. Any more water applied to the coils than the unit can immediately evaporate is wasted water.

Simple idea though. I used the nozzels and the solenoid valve from a misting type humidifier connected to the 24volt control side. It comes on and off with the AC. And check to see if the system's control transformer is large enough to handle the extra component in the circuit.

Neat stuff - old times

 

[WX2MIG]

Residential A/C on average will only cool your house approx 20° below outside temp, so if it's 90°F outside, don't expect it to get muct cooler than 70° inside.
There are an infinite list of variables that will effect this, window area, structural insulation, type of coolant used in the system, and the over all age of the system, but a system in good working condition that was sized correctly for your home should give you a minimum of 20°F cooling....(over ambient outside temp)

Weasel is right about the old Merc ball T-stats, but I prefer the new digital units, and here's why....
With the old T-stats to work efficiently they had to be installed dead level on the wall...(what are the chances that happened)
The temperature sensitive bi-metal coil spring that regulates the merc ball eventually gets loaded up with dust which effects the efficiency of function. The new digital t-stats are extremely accurate, they can fall off the wall, and as long as the wires are still connected it will accurately control the temperature of your home, they are easy to use, and basic units are fairly cheap to buy at Home Depot or Lowe's.

Spraying a mist of cool water onto the condenser coils will help, but only so much. You may be able to coach a couple degrees more of cooling, but that's assuming your system is in proper balance. Nothing will help a system that's leaked it's freon, or was sized incorrectly to begin with.

Another thing to remember is your t-stat is not an accelerator, it will not make your system cool anymore than it's capable of cooling. If you live in an extremely hot climate, the best approach is to keep your windows covered on the east and south sides of the house. Drop the temperature in your home early in the morning, and get it as cool as you can before the outside temperature rises, this way when it hits the hottest point of the day your inside temps won't rise as much, and you'll stay a little more comfortable. When the sun sets and the outside temps fall off, lower your t-stat back to your original comfort level for the evening hours.

One last thing....
With any forced air system, the best and most efficient approach to controlling your inside climate is to find your comfort level, set it, and forget it.....
Programming your t-stat to go up and down only wastes energy with forced air systems because their effects are only momentary. It's different with radiant heating systems since they continue to radiate heat after the T-stat has been satisfied and shuts down the system, but forced air does not continue to radiate, allowing the surfaces inside your home to cool (or heat back up) quicker. The tree hungers would have you believe otherwise, but don't buy into that junk science, if your system is forced air....set it, and forget it.....

 

[Switch Kit]

Thank you for the post WX2MIG , surely sounds like you know your AC as well . I did climb the roof last year and checked the unit out the best that I could , it was very clean through and through.

Although I was going to call a tech but never got around to it to check the refrigerent level in the unit. They charge more in the summer time so I will wait until next spring to do this.

I try like hell to save electricity costs here , and Lord knows the AC's run the bills sky high but we need to be cool at the same time. We do just like you said WX2MIG , once it hits about 75 or so in the house , we close it up with shades and drapes and then set the termostat at 85 (in my case)

it will then turn on and off during the day until the evening when the sun sets , as soon as it hits 80 outside , we shut down the AC and open the house back up.

Here's the thing that was messing with my head the most. I used to set the thermostat at 78 and it would never shut off so that meant it ran all day long ,good thermometers placed through out the house would usually read around 76 to 78 or so . But the electric bill would kill us at the end of the month.

This is when I started to think that the thermostat had a problem ? or out of calobration as WW said, after just setting it at about 85 it seemed ? to work as it should , turning on and off during the course of the day. (IM really hoping this will help my electric bill) it was truly the bill that got me most concerned with my AC this summer and trying to be as comfortable as we can witin reason and cost.

My house is now pushing 30 years old and we have sliding windows through out the house , I know the seals have since deteriorated over time so insulating the place is not perfect by far , but I figure the shades and drapes help us.

From reading what you guys said , it sounds like we are doing as good as we can with what we have . (thank you all for the input on this) as soon as I heard if it's 100 degrees outside , most AC units should read about 20 degrees lower , that at least puts me in the ballpark.

Again I say , thank you all for your time and know how on this subject , it's nice to know that IM doing the best that I can with what I got . Switch Kit

 

[Moleculo]

My house is now pushing 30 years old and we have sliding windows through out the house , I know the seals have since deteriorated over time so insulating the place is not perfect by far , but I figure the shades and drapes help us.

SK, my house was built in '62...it had windows like yours until I finally replaced them 18 months ago. I put in dual pane, Low-E Argon Filled replacement windows. I also replaced a huge, west facing sliding door that went to the patio with the same thing. Total cost for everything was around $6K, and here's the kicker - because the windows & door had energy efficient ratings, there is a IRS tax break to be had for the cost. You keep the energy stickers and show them to your tax guy along with the cost and you get a significant break.

The windows will make a HUGE difference in keeping your house cooler in the summer and warmer in the winter. It has definately made a big impact in my electricity bill...I'm not far from you so you should experience the same thing.

 

[WX2MIG]

Switch Kit....
I held a side job for 20 years with an HVAC company where I did everything from deliver home heating oil, to install heating and air conditioning systems. My last position with that company was quality control inspector for the HVAC installation Dept.....then the economy took a shit and I got laid off....

Mole....
My house was built in 1959, and the windows were total crap. I replaced many with the double pane argon filled vinyl replacement units, and the others I took completely out and replaced with Andersen windows. This place didn't have central air when I bought it, and the original gas fired furnace. Now I have a 90+ efficient furnace with the new R-410 refrigerant air conditioning, and I replaced all the duct work with properly sized, outside insulated metal. I can keep my house at a very comfortable 72° without spinning the electric meter off the wall....

 

[Wire Weasel]

More good advice from all.

SK, did you ever check the temp difference between the room & supply vents? Even for your older system, it should make a least a 20 degree difference. If it's not doing 20, then I'd go ahead and get it serviced now. There's still plenty of summer left and should your unit be a even 1 pound low on freon, that's killing your efficiency and could harm the compressor as the cold returning freon from the indoor evaporator coil is what cools the compressor when it's running.

Otherwise, yeah start tackling the air leakage, bad windows, weatherstripping and insulation issues with the house.

Good luck!

 

[Switch Kit]

good to know about the tax right off , doing my windows would be a tough go right now , but I've had the notion for a while now. I have a local AC guy (don't know him) but may check into him at least taking a look see at my unit . I did ask before about what the temp should be of the air coming from the unit ? I said mine seems to be about 68 degrees via a meat thermometer check , should it be colder then that ?

Well , I've surely learned some things here gentlemen. Thanks . When you live where I live , it surely costs money to stay comfortabley cool July , August and September. I've never been much on the heat . I know others can love the heat index way up there , IM not one of them.

Your right Mole , just a little east from you in the San Bernardino county area , it can even be hotter where your at from time to time. I know it could always be worse concerning my weather but living in the low 90s to low 100s for 3 or more months can truly be a discomfort to me as well as my wallets. I got to sleep and I need to eat.

Makes me wonder how people can even live in Arizona and Nevada during summer ? I could only imagine what there electricity bills must look like ? but at the same time , I would guess to say that most of them have very air tight homes that would more then likely help for better costs when it comes to keeping cool.