Ok, what happened is (and boy do I feel stupid) that in the 6 years that I live here I never once cleaned out the filter for the first floor AC. I replaced the filters upstairs fairly regularly but didn’t realize there was the downstairs one that needed to be cleaned. It was pretty clogged up, and the HVAC guy basically said that the insides there were icing up and not allowing any air through, causing the compressor to turn off.
You are right. I am stupid. Turned the fan on right now, AC off and am letting the thing de-ice.
A fair amount of the HVAC advice is anecdotal, well meaning, but often semi accurate, or just plain incorrect. (and I can say that comfortably after 22 years doing this.)
But you do know your stuff. I can’t remember disagreeing with you, and while I’m a ‘real’ HVAC guy, you’re better than many of the HVAC guys I know who do this for a living.
[QUOTE=Joey P;
That’s all I’m gonna say about it. When we’re ready to jump back into fixing the AC, I’ll be here.[/QUOTE]
Joey over the years I have DYIers work on electrical things when they should not. I am careful about giving advice like take covers off unless I have an idea that the person has some idea about electricity. I have dealt with some scarry stuff following behind someone who was not qualified. 40+ years have showned me that you have to be careful and heads up. Now back to the AC.
We’ve disagreed a few times over the years. Not “No I’m right” type arguing. It’s usually something where I took a guess and you corrected me. But that’s how I learn things. I’m sure I drive all my HVAC guys nuts here, following them around and looking over their shoulders. Some keep quiet, some have specifically said they don’t mind. One has bad hips from a fall 20 years ago and likes the extra set of hands and someone who’s happy to reach into odd spots or climb up and down a ladder one extra time. I’ll give him a hand, he’ll talk for 10 minutes (off the clock) about the hi/low pressure sensor he just replaced.
For the life of me I still get hi pressure and low pressure and their associated sensors and symptoms mixed up. Thing is, we spend just barley not enough money on pro HVAC repairs that it’s not worth it for me to go to school and get an EPA license and do freon work myself*. So if it’s part of the sealed system we call in the pros which means I don’t have much hands on experience with anything that involves opening up that system. But if I’m going to pay them for 20 minutes to sit on their ass while they evacuate it, I’ll usually chit chat with them about the problem. So I at least still learn about it.
*OTOH we save a shit ton with me doing as much as possible myself. Just last week I got to work to find that we had a warm cooler. Turns out we had a bad condenser motor on the roof. $200 and an hour later I had it up and running. A few years ago it was replaced by our normal service. The entire call was about $520 (there was some OT in there) and from the time they were called to the time it was fixed was probably several hours. The fact that I can do this kind of stuff myself is one of the reasons I get paid as well as I do here. I like to finish the job and then find the nearest employee, look them straight in the eye and say “I fix shit”.
Given that design outside temps in the area are/were 90F and are the outside peak Summer temp now is regularly 100F, should we replace old units with larger ones?
(Note that one does not ask this of the local fellows from whom one would buy it. )
In every part of the country there is an appropriate size air conditioner for that climate zone. You start with the climate— a macro consideration.
The micro considerations are included in the “Manual J Load Calculation”, and they include things like wall R values, window U values, shading, building orientation, shading and other things. They are things that are specific to the building.
The size is for a common summer day for that area, and that specific building. You do not want to just go get a bigger unit because it happens to be 100° this week. While that would met your needs during this exceptional heat wave, it would be over sized all the rest of the summer days; a bad thing. (Keep in mind, if you live in Phoenix and 100° is the norm, the Manual J has figured that in)
Over sizing a unit is a bad thing, and not worth the benefit of having the extra firepower the handful of days you could use it.
Yes, they taught us that in a course where we were sizing solar heat and calculated heat loss for each room, given wall size, doors and windows.
We also considered climate and heating degree days.
I drew Fargo, South Dakota. :rolleyes:
It is better to be slightly undersized.
My question, though, centers on having several hot Summers in a row, global warming, and whether we have larger heating degree days now than when the standards where calculated.
My guess is that that would be a gamble. I wouldn’t do it.
I’m not an expert, but the things I’ve read suggest a 1-2° global rise in temp over an extended time; a couple decades.
Along the way we’re having extreme, and erratic weather patterns. I would simply do this:
Make sure your A/C is well maintained and in tip-top shape. Keep your filter clean, and spray down your outside condenser at least twice a summer to keep it running efficiently.
Have it serviced every 2 years, if not every year. (Principally to make sure the refrigerant charge is ok)
If you want to put in a larger unit, go with a half ton larger. That’s 6000 Btus; about the output of a small window A/C.
Keep in mind your ductwork is likely sized for the current unit. Putting in a substantially larger unit without the ductwork to support it will cost you. A lot.
Even in this hot weather most people’s A/C is keeping up; as long as it’s in good working condition.
I got home from work a while ago and my house is coming down at about a degree an hour. Considerably slower then normal, but it’ll get there.
Now, our cooler at work, we actually thought it broke down it was struggling so bad. It never recovered from it’s mid-day defrost cycle. In fact, now that I think about it, I’m going to move the defrost cycle to during the night until the heatwave is over. It’s reach in, self serve cooler, near the front door and the doors open towards the front door. It sucks in a lot of heat right from the outdoors. Which brings me to a question I had for you (raindog). On this particular cooler, we’re on our 4th compressor in 17 years which IMO is about 2 two many. I’m okay with replacing them every 7 or 8 years, but on this unit we’ve been replacing them every 4 or 5 years. Any thoughts on that? Could an undersized condenser do that? It does have a small coil for the how big the cooler is. OTOH, no HVAC guy has ever mentioned it and I’m sure they would have if they thought it was a problem. The system’s been drained enough times that it would have been trivial at that point to swap it out if they thought it would help.
The last time they replaced it they also adjusted the TXV and removed the accumulator (saying it could trap oil which would remove it from the system). They’re hoping that between these two things, it won’t happen again…I’m hoping if it happens in less then 10 years, it’s in less then 5 so it’s under warranty.
Rather then piggy backing on this thread, start a new thread and explain exactly what’s going on, the symptoms, what you’ve tried to do etc…
I’m going to say, you could leave out what the pro’s have done in the 10-12 times that they’ve been out, or at least make that a separate part of the post. Just start with the facts, the noises you hear (especially clicks, clicks can be very important), what you expect, what’s happening or not happened etc.
Also, to make things easier, if you don’t know the actual names, don’t guess. For example, it’ll get confusing if you don’t know the difference between condenser and evaporator and get them backwards. Terms like ‘inside unit’ and ‘outside unit’ are fine.
I FOUND MY FIX!!! I’ve been having a very similar, if not exact same problem with my AC compressor in my central A/C rooftop unit (Goodman 3 ton heatpump) working intermittently. When it did, it cooled fine. However, it would randomly not kick on, mostly during the heat of the day for some reason which led me to believe it was some type of overheating issue. I first replaced the contactor relay (which should be replaced every few years as a maintenance item since the high load going on and off wears out the silver plating on the relay mechanism) However, this did not solve the problem. It turned out to be that on the indoor wall thermostat backing plate, the screw for the compressor control wire was stripped and making an intermittent contact and arcing out occasionally which kept the compressor from turning on properly at all times. THat was my solution so make sure all the tiny colored thermostat wires are making proper contact at the thermostat terminal, are not broken or grounding out and that the screws are tight and not stripped and looose!:smack:
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