BTU’s represent an empirical value. Either the unit is functioning at it’s rating or it’s not. It’s not based on your gut feeling. The people working on the unit can give you the specific numbers showing the unit is working.
That’s fine. When the temperature rises to the point it causes the compressor to run continuously it will eventually seize and you will again be spending money on a hotel room until the situation is corrected.
Multiple people have told you you’re at the low end of BTU size. You don’t seem to grasp the concept that as the temperature goes up it affects the output of the unit. The suggested BTU size per SF of space is based on general temperature expectations. It does not mean it will cool your apartment to your comfort level regardless of how hot it gets.
And to clarify a point brought up earlier. Even if the apartment had 10 pane glass and 20 inch, insulated exterior walls, when it’s 95+ degrees out, it’s still not going to be as efficient because it’s harder for the condenser to dump the heat outside (because the temperature of the cond coils and the air temp are closer together than when it’s, say, 75 out). This can be shown by measuring the output temperature of the unit inside the space to be cooled, then measuring it again while spraying water on the coils. The water will draw off more heat, which means more of the gas condenses to a liquid, meaning more high pressure liquid to expand in the evap coils, meaning more heat they can absorb.
In fact, some businesses will put sprinklers on their roofs (or wherever the HVAC condensers are) to help them on really, really hot days.
And another things, while I’m thinking of it. I can tell you, from personal expierence that when the temps get to the 100ish range, the coolers in my store struggle to maintain proper temp. On those days I’ll often rig up a hose to spray water on the condenser coils, which almost immideatly brings the temp back where I need it (as well as keeping the thermal overload from tripping). And, not that it applies here, I’ll have them skip any defrost cycles during business hours so they’re not trying to recover from that.
Yeah we had a mini heat wave this week and the loaner came through smashingly. It’s night and day. So I am confident about it.
The thing is some things I’m not going to be able to do. It’s a moving river and I wont see the old unit again unless I have them bring it special to me. Then when I want to dump it it’s a pain. My best bet is to let the old dealer get me a brand new one, take the loaner back, and keep the old unit, boom, one transaction. Much preferable to all the logistics of moving big machines in and out that need to be disposed of specially, on my own.
What is testing the unit? The air at the cold vent is 6 inches from the other vent. You just take readings right there in front of the vent? I have a hard time seeing this. It’s a wall unit. The back end is outside. What measurement does one do? To get the delta. Anyone doing that right now? Could you please describe it?
It has occurred to me that the OP’s AC unit might have a broken slinger ring. That would prevent the condensate from helping to cool the coils as Joey P just described. It would also cause an AC unit that was undersized-but-adequate on most days to become inadequate during a heat wave. It would also account for the OP’s perception of a step-change in performance.
I’d have expected the warranty people to notice a broken slinger ring when they checked the compressor, but maybe not. Of course, the OP’s unit may not even have a slinger ring; we can’t be sure because he has steadfastly ignored every request for the exact make and model of his air conditioner.
You were the only one who mentioned “gut feeling.” I said it’s the temperature and my breathing and general well being. IOW a noticeable difference in the rooms.
No reason to lecture someone you don’t know about a situation you cant see or experience for yourself is there?
***You don’t seem to grasp the concept that as the temperature goes up it affects the output of the unit.
This is a meaningless statement. And why make an insult from it? What are you about? We’re having a talk about how and when to replace an A/C unit. and dealing with the details. Valuable info anyone might need at any time. You are not doing that. You are bringing in irrelevancies just to be insulting.
The make has been in this thread already. I am choosing not to say more than that. What is the issue with that? Just do the best you can do. That will be ok with me.
Seriously: if you told us which unit you have, we could tell you exactly where to put the thermometer. If you’re sensing a bit of frustration here, it may be because you’re not helping us help you.
Taping a thermometer to the output vent would be fine—all you care about is that the temperature probe is directly in the cold air, as close to the unit as possible.
For the intake vent, you’re just looking for the place where the unit draws in warm air. You won’t feel a stream of air like at the output vent. But if you think you might know where the intake is, you can blow out a candle there and see if the resulting smoke gets sucked in at that point. If it does, than that’s the intake. Taping a thermometer to it would get you a reasonably good assessment of the intake temperature and thus the temperature delta.
Also, make sure to use the same thermometer for both readings.
As far as finding the delta T that’s been mentioned here. You’ll need a thermometer, specifically some type of probe thermometer (as opposed to an infrared one, unless you’re careful not to hit the metal coils, the plastic cover should be fine).
You hold it against the front grate. This is the temperature of the incoming air. Then, where the air blows out, you’ll hold it right against that grate (not 6 inches away, room air will be mixed with it at that point). That’s the output/exhaust temp. You should have somewhere in the neighbor hood of a 20 degree difference. However, if it’s really, really hot out, that number will be smaller.
I tried, but was unable to find a good picture of someone doing this.
The outside part of the unit has nothing to do with this measurement. If you wanted to meausre the delta T on the outside for some reason, you’d measure the air on either side of the condenser coils, but that really doesn’t apply here.
Also, for good measure, while you’re doing this you could pull off the front panel and hold a dollar bill against the coils. If it the can hold the dollar bill against themselves, it’s a good indication that they’re clean (or at least not filthy to the point that airflow is restricted.
Why on earth are you being so exquisitely coy about the make and model of your air conditioner in a thread you started that specifically addresses your air conditioner?
I’m not sure what else you expect from random strangers on the internet. Besides, we can only work with the information given to us.
If you want an explanation from someone that can see or experience the issue, you’ll have to call an AC repair company. And I can all but guarantee they either won’t be able to get to you for a few days or you’d have to pay double/triple time so they can come after hours. Why? Because they’re booked full of people who’s ACs either broken down or think they’re ACs broke down because it’s so hot out.
Maybe the OP just wants validation that the warranty sucks, instead of additional diagnoses and troubleshooting tips? Between his pride about the transom and the reluctance to provide more details about the A/C unit, it sounds like he knows what he’s doing (or thinks so, anyway) and doesn’t appreciate the second-guessing. Sound about right, drad dog?
Well, here: the A/C warranty sucks, doesn’t cover everything, and the manufacturer evidently doesn’t give a damn about you. Move on and try something else. Probably none of them care about you. There.
There’s nothing more the Internet can tell you without the model details or the actual unit on hand to test with. Your old A/C unit doesn’t work as well as you want it to, you refuse to provide more details or do more tests, you don’t want to deal with the hassle of getting it back, so what other option is there? Replace it. Hope you enjoy your new unit.
That’s a weird thing to say. If you call someone to help you with a car problem, would you just say “I have a Dodge, you figure out the rest”? It borders on rude when you have all these people trying to help and they’re simply asking a few questions so they’re advice actually applies.
I hate warranties that won’t replace my still working products.
If the OP used a credit card, he may be able to use the extended warranty through them.
Your take on things, Reply, sounds about right to me. It also occurred to me that the OP might be subconsciously seeking the board’s “permission” to spend some money on a new unit. That would kind of explain his refusal to take action on any of the diagnostic steps and fixes he explicitly asked for.
The post above confused me a bit, because thus far the OP has insisted in this thread that the perceived drop in performance is recent:
He’s also repeatedly and emphatically rejected all suggestions that his AC unit is underpowered for the current conditions even though it was underpowered last year as well:
It sounds to me like the unit has long been marginal on hotter days. It certainly was a year ago—and that was before he discovered his beloved over-the-door fans.
I’m a little surprised that the OP seems to have forgotten that his AC capacity was marginal last year, especially because it was marginal enough that he resolved to buy a new unit a year ago.
Incidentally, the OP struggled in last summer’s thread to get a handle on the concept of temperature deltas and how they might be measured, much as he has in this thread. To be frank, I suspected that the OP was, for some reason, being deliberately obtuse about the delta T concept—especially after being deliberately and passive-aggressively vague about exactly which air conditioner we’re discussing.
But reading through last year’s thread, I think Drad Dog’s confusion might be sincere. If it is, there’s obviously no shame in that.
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Drad Dog, this is one reason many of us have asked you to measure delta T: if you’d measured temperatures last year, you could have compared those numbers to this year’s to see if there had been an objective decrease in performance in the last 13 months. You’d also know how your original unit compares to the loaner they gave you. I’m not wagging my finger at you—I’m trying to explain why some of us are pushing for specifics. The tone of your responses makes me think you might not understand why we’re asking.
You’ve insisted on the primacy of your subjective impressions, saying things like “I know it’s not cooling like it used to. I’m here and you’re not, so you’ll just have to trust me.”
I’d gently suggest that perhaps you shouldn’t trust you. Richard Feynman famously said that “the first principle [of science] is that you must not fool yourself—and you are the easiest person to fool.”
People get habituated to things like temperature, humidity, scent and risk. Nearly everyone is much worse than they think at estimating things like that—myself included.
Many of us who have posted in this thread are problem solvers by nature and/or profession (as are the technicians who decided that your compressor works fine). We know from experience that we can’t help you in any substantial way without a few critical bits of information.
When you withhold such basic information as temperature deltas and even the make/model of the device in question, you make it really hard for us to engage the way you’ve asked us to.
Your OP asked, in part, how to respond to the warranty center’s assessment that your unit works fine. Well, the delta T measurement is critical to answering your question. That number would likely allow us to say either “the warranty people are full of it—push for a replacement” or “they’re right—your unit is operating within spec.”
You seem to expect an omelette while bristling at questions like “how many eggs are in the fridge?” and “what kind of cheese do you have?” IMHO, that’s odd and legitimately enervating. But my impressions aside, it’s also objectively unreasonable.
I don’t have to see it to explain the math. Your gut feeling is a measure of discomfort and not a measure of temperature change. Nobody doubts your discomfort.
It’s not a meaningless statement. It’s the entire thread. Your gut feeling of the unit’s functionality isn’t an empirical number. The tech working on the unit will measure the delta and tell you if it’s in spec or needs repair. It’s one or the other. You’ve been told how to check it yourself so you are better informed on where you stand. At some point it will get too hot to provide for your needs. It might be 96 degrees and 70% humidity. You’ve been empowered with information to help you diagnose the situation going forward.
I’m sorry if you feel insulted. It was not my intention. But you appear to be locked in to thinking the old unit is not working at capacity without any factual numbers to back it up. It could be bad or it could be function to spec. In fact, it could be working to spec and your building is only putting out 100 volts which will cause it to under-perform and likely damage it. Or you could experience low voltage in your area when the power grid is under load. These are the things you can check yourself or have a friend do for little or no money.
I have introduced the idea of adding an additional unit for 2 reasons: as a backup in case the other one fails, and to take the strain off the other unit. You cannot expect to run a compressor 24/7 during an extended heat wave without risk of failure. If the main unit fails then the cost of going to a hotel room is already covered by a small unit for the bedroom.
What everybody on this thread is trying to do is give you the tools to diagnose the problem and make decisions going forward. I hope things work out for you.
Confusion about how a thermostat works is far from rare. I used to work in a building that had a back entrance through a storage area. The outer doors were normally left open, even in the winter; there was a fan heater right over the door and a thermostat on an adjacent wall. As you can imagine, the heater fought a losing battle over the cold air coming in through the doors.
In cold weather, many people would wait for their ride home in that area, and someone would always turn the thermostat up to 30 degrees, even though the fan was already running on the mistaken idea that it would warm up more. Of course, once the room was empty and the doors closed, the room would heat up to sauna-like temperatures. In the end, the thermostat was replaced with one that had no access for changing the setting.
I get that a lot at my work as well. At night (in winter), we’ll turn the t-stat way down. It might take an hour or two to feel warm in the morning, yet everyday people (usually the same people) will complain about how cold it is ask for someone to turn the temperature up. No amount of explaining that “it’s set to 72 and it’s only 70 in here, you’ll be just as cold for just as long if we set it to 80” gets through to them*.
In college we had these junky hydronic baseboard heaters, and to make it worse, these dorms had 7 people in them, they had a main/living room and 4 bedrooms and one t-stat to control the heaters for the entire unit.
On move in day, the RA gave us a really good tip about them. He said that if you’re cold or hot, adjust it by just a tiny bit (the dial had numbers, not temps, so move it from 7 to 8 or 6 to 5 etc) and wait a day or so before adjusting it again. He said he sees people constantly fighting with it all year long. They’re cold so they turn it up to 9, then an two hours later it feels like a sauna so they turn it down to 2 and back and forth all winter, never just putting it at 5 and seeing what happens.
Even after the RA said this and I tried to explain it to them over and over they still did it. I found it was easiest to keep my door closed, let them do whatever they want with the t-stat and I just opened and closed my window as necessary.
This is the same reason you have to let the temp in your fridge settle for a few hours or a day before you adjust it again.
At work, adjusting the temp on our big walk in cooler can take days to get right.
I just had a similar discussion to Joey P & Bob++ with my 22y/o daughter who lives in a dichotomous A/C world: set to 16C with the fan on “high” blasting cold air or completely “off”. I tried to explain: “OK, once more… turning the temperature down to 16C does not make the room cool off any faster and does not change the temperature of the air blowing out, leave it at comfortable temp and don’t touch it!” Response: a blank look, she just doesn’t get it. :smack:
My theory about why most people don’t understand how a thermostat works is because most people erroneously think a thermostat controls the a/c unit in their vehicles (I know some some do, but most don’t). People adjust the temperature of the air blowing out, erroneously thinking they’re changing the thermostat and that all thermostats work that way.
I worked in office buildings and retail stores. The thing that I have never understood. If the person is cold they know how to turn the stat up, but when it gets hot they don’t know what to do. Or if the person is hot they know how to turn it down but not up. I will get a hot call to a space, stat is setting at 85 degrees and space is 76 degrees. Or I will get a cold call stat set to 55 degrees space 68. I just smile sweetly and tell them everything is working properly, and they need to keep an eye on their fellow employees who have no common sense.
I will also give an anology. If you are driving on a freeway and the speed limit increase from 55 mph to 70 mph, do you puta your foot down on the gas as you turn the key to start the engine? Nope? Why not? Because the engine is running. If you stat is 2 degrees higher or lower than the space the system is already wide open and everything is working. Turning up the stat will only over cool or over heat the space. And if the everything is not working adjusting the stat will not make it work.
And finally if I get too many call backs I just make sure that I have something going on that I have to complete before responding.
