Any HVAC guys out there?

I have a thermostat question, it's kind of a dumb question, but I figure I would ask so I am sure it's all good.

So a few days ago I purchased a new thermostat, it's a Lux TX9600TS Touchscreen. I wanted to get something programable, so I can have it automatically have it cool down at night, with heat/ a/c. So obviously I have only used it with the a/c so far, and what my issue is, is that I keep it set at 74, but what the thermostat seems to do is cool it to 73 and then lets the temp work its way back up to when its about to get to 75 then kicks on again. Of course it does not mention this in the manual. So I think I get the theory of it, but since it is trying to cool the house down to 73, instead of 74, it seems to have to work harder and run a little longer to get to that point.

Yesterday was pretty hot, I'm not sure what the high was, but it was in the upper 80's and very humid, so it was running most of the day, but again it was running to get it to 73.

Here is a pic, where you see it is set at 74, yet the room temp is showing 73.


So anyway, I guess my question is, is this a normal function of new or any thermostats you guys have seen? Also is it bad for my a/c to be running longer to get it to that temp?

Thanks in advance.

Dave

 

There is a differential that in some thermostats is programmable, (1 degree below to one degree above) other wise your condenser will cycle off and on too much to target only 74 degrees, Read the instructions on how to open or close that differential window but it looks like its doing what it is supposed to.

 

That t stat looks fancy enough that it has a selectable sensitivity - as your home temp fluctuates, you can program the thermostat to monitor and activate at different intervals - usually 1/2 a degree to 2 degrees, and/or in between the two.

This should not, however, keep you from seeing your room temp match the set point more often than not.

Definitely read through the manual if you haven't already.

 

Thanks. There is something in the directions about the swing value, which is what I assume is what you are talking about. Honestly, I found it alittle confusing. It seemed to not change anything when I messed with it, but I don't know.

 

all thermostats actually do that ... even old mercury bulb thermostats they have a heat and cool anticipator where the digital stats have a algorithim it goes off of but this is normal

 

Ya I think your talking about the same as 2012 Tacoma is, but like I said I'm confused by the whole thing. What it does is, is it runs till its down to 73, then it lets the temp build up to 74, and what it seems to do is, just before it reaches 75, it kicks back on, and then takes it back down to 73. Which is cooler than I want it. Gets alittle chilly in there.

 

My thermostat refers to that as the "swing" and has a value that I can set to adjust it, from 1 to 10. It's a 7-day that's at least 10 yrs old now. On the extreme end, it will run well past the set point before shutting off. That's the most efficient, because as the system runs, it's reaching it's point of efficiency and removing the most humidity. But it's not the most comfortable because the temperature differential is so wide. As for the efficiency, maybe the best analogy is that it's like a car "warming up" before it will get the best gas mileage. At the other end, the system will shut off sooner and kick on again sooner. This will be the least efficient, but maybe more comfortable to you since the temp stays closer to the set point. It will not remove humidity very well. That can make you think it feels warmer, so you will possibly bump it down a degree.

My system is not a high seer level - just a 13. If you have a variable speed unit, make sure the thermostat supports that as well. These days you have to make sure the two are fully compatible.

 

Interesting, I did not know that. Thanks.

 

Ok, ya I read in the manual about the swing. I found it alittle confusing. But what you said makes sense.

Ya I actually just got a new a/c installed cause the old one died. Mine is also a 13 seer, which from what I have read is the lowest you can get now. It cools great now, and with the wife being pregnant, it makes my life better! lol.

Anyway, I don't have a variable speed unit, that much I know. The thermostat seems to work great with it, just the temp thing is weird to me. But I get what your saying about the humidity, and efficiency.

I think what I will do is set that swing to maybe half way. I'll see if I like that better, and if it is still cool enough for me.

 

You sir, have to come to Arizona.

 

LOL, I have been, and I actually liked the heat out that way. Its dry, compared to the humid shit we get here. I hate the humidity! 88 does not sound as bad as the 100's, but ad humidity, and f**k it sucks! I think Florida was the worst I ever felt the humidity. Good god, it was awful!

 

lol, i didn't catch the humidity part...in that case, i've been to mazatlan mexico during the summer...temp around 80-85 degrees...but humidity at 100% it seemed...shower, went outside, automatically drenched in sweat sitting under a tree eating mangos..lol.

 

lol, ya, that is no good. A couple weeks ago when my a/c was broke, it was getting hot, took a cold as I could take it shower, got out, sweating! @#$($%^*!

Oh and a little weather schooling for ya, the dew point is what you want to pay attention to in humid areas. Humidity can be relatively low, but if the dew point is high, that's when you feel the humidity. I think its like if the dew point is higher than 30 or 40 degrees, its gonna feel hot.

 

Well, just a quick update, if anyone wonders... I messed with the swing value on the thermostat, and didn't change the fact that it still cools down below the set temp, like I said i get the theory behind it, its just that 74 is just right for me and the wife, and 73 is just a little chilly, maybe I'll just set it at 75.

When I messed with ther swing, it only, from what I could tell, reflected on the warmer side, so being set at 74, it allowed it to warm up more before it kicked on, rather than kicking on before it hit 75.

Still weird to me, I have had plan old digital thermostats in the past, and even if they did run past the set temp, they always showed that the room temp was at the set temp. Strange to me.