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If they are good ac techs they are checking the unit itself first ….not the effect on the room .
the temperature change it is capable of doing to a room is secondary initially
Simply because it is 100 out and 80 inside is no indication the unit is fully charged..perhaps that size unit And the heat load it has on it should be seeing in the 70s.
So simple answers to complex questions are usually not the correct answers.
First thing I always do is check system pressures to see what the system is doing and if it is fully charged .
Those pressures will tell me all I need to know about the charge , compressor efficiency and the fact the condenser and evaporator coils are not blocked and the air handler is working fine .
An ac system is a very specific balance of pressures and internal refrigerant temperature and unless something is causing an imbalance the pressures tell me when things are right in the unit .
Once the unit itself is analyzed then you broaden the searchto outside factors like
are dampers balanced and open ?
Is the stat working ?
We’re appliances added that create heat ?
Renovations and add ons making the unit to small ?
Change in window treatments that are now not blocking the heat coming in as well?
Etc etc .there are lots of other factors including the unit is just undersized
Last edited by mathjak107; 04-21-2022 at 09:37 AM..
One thing I want to add is that back in the 1970s , the reason I became an hvac tech is because it is the one area few really understand …
Guys would rebuild car engines and transmissions, even build their own house .
But no one dabbled inside the sealed systems of refrigeration and ac units …
So very few people really understood just how to troubleshoot units ..
And as always that which others can’t or won’t do for themselves is where the money was.
It really was a closed business prior to the technical schools . Dads taught their sons and so on and so on .
Once I learned my way around I couldn’t believe how easy it was to troubleshoot them.
I was like I hope no one else realizes this. Lol.
But it became a so popular I moved on to the complex control systems in malls and theaters, where again few knew..
So it has been an interesting career as i morphed through different related fields using my basic skills .
Today I retired and teach motor controls and variable frequency drives one day a week As it applies to water pumping plants and sewage treatment plants so it has been one long strange trip all based on the basic hvac skills
If they are good ac techs they are checking the unit itself first ….not the effect on the room .
the temperature change it is capable of doing to a room is secondary initially
Simply because it is 100 out and 80 inside is no indication the unit is fully charged..perhaps that size unit And the heat load it has on it should be seeing in the 70s.
So simple answers to complex questions are usually not the correct answers.
I was responding to ONLY the question about the temperature. Obviously a decent tech checks more than that, but that is certainly ONE thing that they ALWAYS test.
I was responding to ONLY the question about the temperature. Obviously a decent tech checks more than that, but that is certainly ONE thing that they ALWAYS test.
I want to make sure that every here Knows that , that is no indicator the unit is fully functional and charged .
What a unit can pull down too is dependent on lots of factors space wise and assuming because you see 20 degrees as a delta that the unit is fine is a mistake…
Many designs for warm locations are designed and sized to see more than that.
Our unit in pa was sized to provide as low as 65 on a 95 degree day.
When we bought the house I checked the unit myself . It was easily doing 20 degrees but it also had a small leak and was low on refrigerant as evidenced by the pressures
20 degrees is what the HVAC guys (at least the ones that I know) use as a standard for testing the system.
When is the last time you had your system checked out? Might be time.
I know about the 20 degrees as I said in the OP. We just had it checked, cleaned and serviced. It's only a year old. It's only cooling a small bedroom.
One thing I want to add is that back in the 1970s , the reason I became an hvac tech is because it is the one area few really understand …
Guys would rebuild car engines and transmissions, even build their own house .
But no one dabbled inside the sealed systems of refrigeration and ac units …
So very few people really understood just how to troubleshoot units ..
And as always that which others can’t or won’t do for themselves is where the money was.
It really was a closed business prior to the technical schools . Dads taught their sons and so on and so on .
Once I learned my way around I couldn’t believe how easy it was to troubleshoot them.
I was like I hope no one else realizes this. Lol.
But it became a so popular I moved on to the complex control systems in malls and theaters, where again few knew..
So it has been an interesting career as i morphed through different related fields using my basic skills .
Today I retired and teach motor controls and variable frequency drives one day a week As it applies to water pumping plants and sewage treatment plants so it has been one long strange trip all based on the basic hvac skills
Yes, everything you said was over my head. I'll have my husband read it and see if he can decipher.
We built 3 houses with our own 4 hands but we never attempted the HVAC or concrete. Those we farmed out. Way too technical and who wants to cut aluminum.
My Honeywell stat has a probe in the cold air intake and on the plenum out of the A coil. It measures the delta between the intake and the output, I assume as a measure of efficiency.
Many systems today have variable speed fans and compressors
They have sensors to determine how long things need to run and what speed so as to pull as much humidity out at lower speeds before going to higher speeds
I googled this and it looks like generally 20 degrees of cooling.
But I have found ours won't go below 72 no matter what the outside temp is. I've experimented with setting it at 68 but it won't go that low. 72 is it. I mean, 72 is OK but I'm just curious why that is the limit. Under the covers at night I'd like it to be the recommended sleeping temp. of 68.
The outside temp. is generally around 80, day and night. So asking for 68 doesn't seem out of line. It's quite humid too, here on the equator.
Everyone has split units here so it's only cooling one room. In this case the bedroom. We have this unit and it's only a year old.
We have those same units here in Jamaica… Are you sure that unit is the correct size for your room? We have no problem getting down to 68° using those units. And it’s hot and humid here as well.
Even in the summer when it’s 100 to 106°, we have no issue getting the AC down to 68. These aren’t your typical HVAC units… They’re much more efficient, and much better at keeping a place cool. You might want to have your unit serviced.
Yes, everything you said was over my head. I'll have my husband read it and see if he can decipher.
We built 3 houses with our own 4 hands but we never attempted the HVAC or concrete. Those we farmed out. Way too technical and who wants to cut aluminum.
Is a complete enclosed HVAC system common in Ecuador? It’s not common here in Jamaica.
We have a 5600 square-foot solid poured concrete home, there’s no way in heck we could/would put a ducted HVAC system in this house. It wouldn’t make any sense. It would be extremely expensive to import the system, then to have it properly installed and not to mention having it maintained.
I don’t know of anyone that has an American style HVAC system here… We all use inverters, even commercial settings ( with the exception of high end grocery stores ie: Costco) uses inverters. It just makes more sense.
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