Author Topic: A/C Issues - Any ideas?  (Read 2580 times)

nirvines88

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A/C Issues - Any ideas?
« on: August 14, 2017, 05:37:44 PM »
I've got a heat pump that seems to work pretty good in moderate temperatures (50-85 F).  However, in the summer, when it's consistently 90+ degrees and humid, it doesn't keep up.  In the summer mornings, if it's 78 degrees inside and I turn it down to 75, it can do it no problem (outside temperatures around 78-80 in a.m.).  However, if I try the same thing in the afternoon (when it's in the 90s outside), it can't keep up and the temperature actually continues to rise into the low 80s!  It's pretty consistently 80 degrees in the house from 4 p.m. and on.  FYI the air coming out of the vents feels cool.  Also, I've got a 1200 sq ft house, single story, about half my house is in the shade from trees.  A/C unit is about 9-10 years old (hoping to get a couple more years out of it!).  Lastly for any experts the unit is a Carrier Heat Pump: http://www.carrier.com/commercial/en/us/products/packaged-outdoor/outdoor-packaged-units/50vt-a/

Here are some things I've done for the unit:
-Cleaned A/C unit - removed leaves from fan area, sprayed down intake vent thingies, cleaned drip pipe
-Consistently changed my indoor filter every month
-Had thermal expansion valve (TXV) replaced last summer, and the fluids topped off (this fixed the issue last summer when A/C wasn't working at all for a few weeks; EDIT: detector did NOT detect any fluid leaks)
-I've also done the small things to help it keep up: Keep all window blinds closed, doors and storm doors closed, all vents open, house circulatory fan on, fans in rooms to make it seem cooler to the humans

Any ideas as to what the culprit is? 

Bracken_Joy

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Re: A/C Issues - Any ideas?
« Reply #1 on: August 14, 2017, 06:50:36 PM »
Not clear from your post- is this a new issues? Or did you just buy the house? Or has it always been like that?
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nirvines88

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Re: A/C Issues - Any ideas?
« Reply #2 on: August 15, 2017, 04:56:06 AM »
I've had the house and same heat pump for 3 years.  First year it worked fine, second year I got the TXV replaced and coolant topped off and it started working fine again, this summer it's having the issues described above. 

Fishindude

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Re: A/C Issues - Any ideas?
« Reply #3 on: August 15, 2017, 08:13:28 AM »
I'm no AC man but guessing you have a problem with the AC coil?  Get a tech to come look at it.

Bracken_Joy

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Re: A/C Issues - Any ideas?
« Reply #4 on: August 15, 2017, 08:27:25 AM »
Asked the husband. We've had no end of grief from our heat pump, and he's an engineer, so of course he loves deep dives into stuff like this. His thoughts:
1- the new TX valve might be restricted. This is an adjustment a tech can make.
2- may not have the spec amount of coolant in the lines.

He says "they've already hit the low hanging fruit". Strategy in the meantime "take advantage of colder nights and super cool the house then. Your thermal mass will help keep the house cool during the day".

I think his feedback comes down to- you've done all the obvious stuff, you probably need a tech at this point.

(If any of this is unclear, I apologize. I was playing scribe while he was talking, did my best).
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Nately

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Re: A/C Issues - Any ideas?
« Reply #5 on: August 15, 2017, 09:04:06 AM »
I'm guessing you've got a slow refrigerant leak somewhere, so it's working inefficiently.

GuitarBrian

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Re: A/C Issues - Any ideas?
« Reply #6 on: August 15, 2017, 09:18:47 AM »
It sounds like you are low on refrigerant. Have a tech come out, diagnose the issue. If your unit uses r22, most places charge $100/lb. You can buy a tank your self for less than $20/lb on eBay. If you have a 410a unit, then refrigerant is must cheaper. If the unit you linked is correct then it is 410a...
Can't really tell anything until you get a gauge on it.
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nirvines88

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Re: A/C Issues - Any ideas?
« Reply #7 on: August 15, 2017, 10:15:30 AM »
Thanks for responses.  I bit the bullet and called out a tech guy for tomorrow.  I agree with some of your guesses and that it fits the bill for dirty coil or refrigerant, but will find out tomorrow!  Will post an update with the culprit.

lthenderson

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Re: A/C Issues - Any ideas?
« Reply #8 on: August 15, 2017, 10:26:43 AM »
In the summer mornings, if it's 78 degrees inside and I turn it down to 75, it can do it no problem (outside temperatures around 78-80 in a.m.).  However, if I try the same thing in the afternoon (when it's in the 90s outside), it can't keep up and the temperature actually continues to rise into the low 80s!  It's pretty consistently 80 degrees in the house from 4 p.m. and on.  FYI the air coming out of the vents feels cool. 

Any ideas as to what the culprit is?

My guess is that there is actually nothing wrong with your system. I'm guessing your thermal heat load coming in from the sun shining through your windows is simply more than heat pump can keep up with. I would install curtains to block the afternoon sun and look into the insulation of your house to make sure it is adequate. Just installing curtains or blinds to block afternoon sun makes a HUGE difference in the amount of energy required to cool a house during the summer.

Bracken_Joy

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Re: A/C Issues - Any ideas?
« Reply #9 on: August 15, 2017, 10:32:22 AM »
In the summer mornings, if it's 78 degrees inside and I turn it down to 75, it can do it no problem (outside temperatures around 78-80 in a.m.).  However, if I try the same thing in the afternoon (when it's in the 90s outside), it can't keep up and the temperature actually continues to rise into the low 80s!  It's pretty consistently 80 degrees in the house from 4 p.m. and on.  FYI the air coming out of the vents feels cool. 

Any ideas as to what the culprit is?

My guess is that there is actually nothing wrong with your system. I'm guessing your thermal heat load coming in from the sun shining through your windows is simply more than heat pump can keep up with. I would install curtains to block the afternoon sun and look into the insulation of your house to make sure it is adequate. Just installing curtains or blinds to block afternoon sun makes a HUGE difference in the amount of energy required to cool a house during the summer.

I wondered that too, but OP said the last 2 years the system kept up just fine. So it's a change. Unless this summer has just been more extreme than previous years.

A phenomena happening here in Oregon (and I'm sure other places)- a lot of AC units are now undersized, since we're getting way longer hot spells in the summer (esp the last 2-3 years) than we ever did before. Thanks climate change! =\ This also sucks because AC actually isn't all the common in this part of Oregon period, traditionally, but it's pretty much a necessity now.
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lthenderson

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Re: A/C Issues - Any ideas?
« Reply #10 on: August 16, 2017, 10:08:15 AM »
My guess is that there is actually nothing wrong with your system. I'm guessing your thermal heat load coming in from the sun shining through your windows is simply more than heat pump can keep up with. I would install curtains to block the afternoon sun and look into the insulation of your house to make sure it is adequate. Just installing curtains or blinds to block afternoon sun makes a HUGE difference in the amount of energy required to cool a house during the summer.

I wondered that too, but OP said the last 2 years the system kept up just fine. So it's a change. Unless this summer has just been more extreme than previous years.[/quote]

A lot of times it is related to trees. They get old, die and are cut down and all of a sudden, a west facing window always in the shade is now getting direct sunlight for four hours a day. I don't know the exact statistics but I've heard one normal sized bay window in full sunlight can produce more BTU's of heat than can be compensated by the average sized air conditioner.

Spork

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Re: A/C Issues - Any ideas?
« Reply #11 on: August 16, 2017, 05:06:24 PM »
My guess is that there is actually nothing wrong with your system. I'm guessing your thermal heat load coming in from the sun shining through your windows is simply more than heat pump can keep up with. I would install curtains to block the afternoon sun and look into the insulation of your house to make sure it is adequate. Just installing curtains or blinds to block afternoon sun makes a HUGE difference in the amount of energy required to cool a house during the summer.

I wondered that too, but OP said the last 2 years the system kept up just fine. So it's a change. Unless this summer has just been more extreme than previous years.

A lot of times it is related to trees. They get old, die and are cut down and all of a sudden, a west facing window always in the shade is now getting direct sunlight for four hours a day. I don't know the exact statistics but I've heard one normal sized bay window in full sunlight can produce more BTU's of heat than can be compensated by the average sized air conditioner.
[/quote]

Yeah.  We cut down a large mature (and dying) tree that provided southern shade to the entire roof.  This was an immediate $50/mo increase over previous years.
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EricEng

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Re: A/C Issues - Any ideas?
« Reply #12 on: August 17, 2017, 02:18:47 PM »
Air from the vent shouldn't just be cool, it should be significantly colder like 20 degrees.  The air will feel cool just from blowing across your hand like a fan while not actually being colder.  Check the cooper coolant return line from the exterior unit as it enters the house.  It is usually covered with foam insulation you can peel.  If it is not cold to the touch, the exterior unit is failing to cool the coolant enough.  That could be, as the others said, insufficient coolant or the compressor could be failing.  It does help if you AC unit is shaded, but that is not a massive factor normally.  You could also check at the radiator on the interior unit, the fins the air blows over should feel almost icy to the touch.

Now if you measure the temperature of the vent air and it is blowing cold and your house is still staying hot, then either you have a severe insulation leak or the unit is not large enough to support the space.

Capt j-rod

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Re: A/C Issues - Any ideas?
« Reply #13 on: August 17, 2017, 03:14:06 PM »
I do it for a living. If it is low on charge it will usually ice up. If the coils are dirty then you will lose capacity. You can't just spray water on it. You pull the disconnect to the outdoor unit (power). Pull the shroud off of the outdoor. The fan in the lid needs to be disconnected. Do not damage the fins on the coil. Now spray water from the inside of the coil to the outside. Reassemble all of the components. Make sure the fan in the outdoor unit is running correctly.
As for the refrigerant charge... The unit either runs on 410A or R22. It is illegal to purchase or handle these gasses without a license. Beware the "cheap" gasses. R22 frost is not r22. People recover old refrigerant and rip people off. My cost on a jug of R22 is $900. 410a is a newer refrigerant that is much better priced. They are not the same. 
Finally where I see a lot of issues is people like to shut off their units when they aren't home and let the temperature rise. The outdoor to indoor temperature is one of the delta T or difference in temperature. Air conditioning is designed for a 5-10 degree delta. If it's 90 and you want 70 the unit can't do it. The txv is very possibly bad. If the system is 410a and was installed without using nitrogen in the line during the brazing process, then it is restricted with crud.
Last thing that comes to mind is cycle it into heat mode and then back into cooling. Sometimes the reversing valve screws up.
Let us know how it turns out... Sorry about the long winded reply
« Last Edit: August 17, 2017, 03:16:10 PM by Capt j-rod »

EricEng

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Re: A/C Issues - Any ideas?
« Reply #14 on: August 17, 2017, 04:18:53 PM »
Quote
Finally where I see a lot of issues is people like to shut off their units when they aren't home and let the temperature rise. The outdoor to indoor temperature is one of the delta T or difference in temperature. Air conditioning is designed for a 5-10 degree delta.
Lots of people do this and it works fine.  It will cost more to keep it cool than cool it back down later because the larger the delta between inside and out the faster heat transfers in.  You are keeping a larger delta for a long time if cooling an empty house.  I let my house get up to about 80-85 during the day, and it cools back down to 73 in 30 mins when I come home.

Your second part makes no sense.  AC thankfully does more than just 5-10 degrees delta from outside temp.  Otherwise no one would survive Texas summer's of 110+ degrees.

fiStressRelief

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Re: A/C Issues - Any ideas?
« Reply #15 on: August 17, 2017, 05:00:34 PM »
Did they ever come back and check refrigerant pressures after the new txv was installed?  I'm not a tech, but my understanding is they need to do so once the txv fully opens up during peak summer cooling.

So either that or you have a slow leak, most likely in your indoor coil.  I've been through this with mine where the copper tube coils made about 10 years ago develop pin hope leaks due to formicary corrosion.

Good luck

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GuitarBrian

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Re: A/C Issues - Any ideas?
« Reply #16 on: August 17, 2017, 07:13:41 PM »
410a is a non ozone depleting gas. People were suppose to be able to buy and install it just fine. Then the AC companies and techs lobbied to keep their business.

At $900/tank for r22, that is $30/lb. Even a ridiculous 50% markup is $45/lb. This is the MMM forum, not the "Here's how to pay $100 a pound. A feel good 233% markup."

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Capt j-rod

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Re: A/C Issues - Any ideas?
« Reply #17 on: August 17, 2017, 07:33:20 PM »
Look guys, I'm only giving the OP the real numbers and the potential problems an solutions. I have done HVAC for 18 years. I have an engineering degree and I design commercial and residential HVAC systems. I run my own business which is very successful with many happy customers. You can run your system however you want. If you doubt my theory on letting the temperature rise then you are forgetting about thermal mass of objects as well as the humidity control. You don't just cool the air in your house, you also have to transfer the BTU's out of the items inside the home. Think of it like driving your car in stop and start traffic or setting the cruise control on the highway at 55. Which burns more gas? Try running a 5-8 degree set back. More than that and it is most likely not saving electricity. We like to see a 15-20 degree delta on our indoor coil. If you can overcome a large delta quickly on a 95+ degree day then your equipment is most like oversized for the application.
    The EPA regulates the refrigerants and the supply house sells it to licensed contractors like myself. I didn't make the rules, I don't set the prices. I also don't gouge $100/lb for R22. The companies that are servicing your equipment have large overheads like vans, employees, shops, worker's comp, insurance, blah blah blah... They can't give it to you at cost.
     I suspect that the system either has a leak or is potentially overcharged. To figure this out you need gauges, temperature probes, a sling psychrometer, a pressure enthalpy chart, and some good training. I also hope that the previous tech pulled a full vacuum down below 400 microns after he installed a new TXV. If not there may be moisture and contaminants in the system that causes damage. In order to properly charge a TXV heat pump it must be done in the cooling mode and sub cooling must be properly calculated. A proper charge is CRITICAL for getting the advertised efficiencies out of your equipment. HVAC is a highly skilled trade. There are basics that I described earlier, but it quickly gets complicated.
     I always appreciate good help and insight from the members of this forum. I finally found a topic I can weigh in on, and people shoot  try to shoot the shit out of my reply. Best wishes to the OP and feel free to ask any questions.
« Last Edit: August 17, 2017, 07:46:19 PM by Capt j-rod »

GuitarBrian

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Re: A/C Issues - Any ideas?
« Reply #18 on: August 18, 2017, 01:38:18 AM »
Look guys, I'm only giving the OP the real numbers and the potential problems an solutions. I have done HVAC for 18 years. I have an engineering degree and I design commercial and residential HVAC systems. I run my own business which is very successful with many happy customers. You can run your system however you want. If you doubt my theory on letting the temperature rise then you are forgetting about thermal mass of objects as well as the humidity control. You don't just cool the air in your house, you also have to transfer the BTU's out of the items inside the home. Think of it like driving your car in stop and start traffic or setting the cruise control on the highway at 55. Which burns more gas? Try running a 5-8 degree set back. More than that and it is most likely not saving electricity. We like to see a 15-20 degree delta on our indoor coil. If you can overcome a large delta quickly on a 95+ degree day then your equipment is most like oversized for the application.
    The EPA regulates the refrigerants and the supply house sells it to licensed contractors like myself. I didn't make the rules, I don't set the prices. I also don't gouge $100/lb for R22. The companies that are servicing your equipment have large overheads like vans, employees, shops, worker's comp, insurance, blah blah blah... They can't give it to you at cost.
     I suspect that the system either has a leak or is potentially overcharged. To figure this out you need gauges, temperature probes, a sling psychrometer, a pressure enthalpy chart, and some good training. I also hope that the previous tech pulled a full vacuum down below 400 microns after he installed a new TXV. If not there may be moisture and contaminants in the system that causes damage. In order to properly charge a TXV heat pump it must be done in the cooling mode and sub cooling must be properly calculated. A proper charge is CRITICAL for getting the advertised efficiencies out of your equipment. HVAC is a highly skilled trade. There are basics that I described earlier, but it quickly gets complicated.
     I always appreciate good help and insight from the members of this forum. I finally found a topic I can weigh in on, and people shoot  try to shoot the shit out of my reply. Best wishes to the OP and feel free to ask any questions.

I agree about the thermal mass. It can take hours here in Phoenix to pull the temp down, even if the system is working correctly.

For the OP we are all speculating until a tech comes out and has a diagnosis.
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EricEng

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Re: A/C Issues - Any ideas?
« Reply #19 on: August 18, 2017, 10:12:33 AM »
Quote
If you doubt my theory on letting the temperature rise then you are forgetting about thermal mass of objects as well as the humidity control. You don't just cool the air in your house, you also have to transfer the BTU's out of the items inside the home. Think of it like driving your car in stop and start traffic or setting the cruise control on the highway at 55. Which burns more gas?
I know my physics quite well as I am also an engineer.  I'm just pointing out a common misconception that I see spread by HVAC techs.  You can know how to install and repair something without having physics of thermal heat transfer right, hence the common and understandable mistake.  Your analogy of a car is quite flawed, although it would actually support my suggestion of running it a lot at the end of the day instead of on/off trying to maintain 72 degrees for an empty home.  That said, the analogy doesn't apply to this circumstance in the least.

The larger the difference in temperature between two objects, the faster the heat transfer between them.  Thus, the cooler your house is during the day the more heat/energy that transfers in.  As you correctly point out, some of this heat is in the air and some is absorbed by the structure and physical objects themselves which slowly release the heat later if you cool back down.  However, law of conservation of energy states energy is always preserved no matter where it goes in the isolated system/house so we can ignore this aspect.  The AC unit transfers heat/energy out of the home.  The greater the delta between the coolant and the home interior the more efficient it is as it will absorb more heat which each pump, which is an added perk for my use case.

By maintaining a low temp all day you are causing more heat energy to be absorbed by the home.  In the extreme case, consider I have a house with the system off for a week.  It would eventually reach the same temp as the outside and would stop absorbing energy except when the exterior changed (yes, sun rays will play into this some).  While your house would be constantly absorbing more energy as it stays cool.

You are right that humidity is a factor.  You don't want to totally turn the system off and let humidity get out of control either.  This will depend on your local climate though.

Capt j-rod

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Re: A/C Issues - Any ideas?
« Reply #20 on: August 18, 2017, 01:41:22 PM »
I give up... I will sell my tools, truck, and company. I'll also turn back in my PE and stop ripping people off. I will also notify ASHRAE, ACCA, Trane, Carrier and Honeywell that we are all idiots and we have wasted our lives and careers. All of those data logging control systems that were installed are woefully wrong. EricEng has solved the crime and we are all guilty. Everyone needs to go home and reap the savings. I'm done with this bullshit. I'm going back to being a lurker on the site.

fiStressRelief

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Re: A/C Issues - Any ideas?
« Reply #21 on: August 18, 2017, 05:12:47 PM »
I give up... I will sell my tools, truck, and company. I'll also turn back in my PE and stop ripping people off. I will also notify ASHRAE, ACCA, Trane, Carrier and Honeywell that we are all idiots and we have wasted our lives and careers. All of those data logging control systems that were installed are woefully wrong. EricEng has solved the crime and we are all guilty. Everyone needs to go home and reap the savings. I'm done with this bullshit. I'm going back to being a lurker on the site.
I'm not sure why you feel the need to take your ball and go home.  IME it is rare to find a tech with an engineering degree, so I think that makes your perspective especially valuable.  However that doesn't mean you shouldn't  be expected to defend your statements. Do so as an engineer would.

In my area any bozo with a few hours of training can call themselves an HVAC tech.  It is rare to find one that can describe the science behind what they do. 

Fwiw, I also let my house go to 84 during the day mostly because that is what the power company incentivizes.  However there are also benefits for reducing equipment starts and allowing for full efficiency and yes my system is oversized.

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Bracken_Joy

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Re: A/C Issues - Any ideas?
« Reply #22 on: August 18, 2017, 05:49:15 PM »
j-rod, I will say, I really appreciated your input. I don't know enough to tell my own left foot from an AC unit, but it was still a very interesting read, and I like to think it chipped away a tiny bit more of my HVAC ignorance. Honestly, even seeing the debate itself was quite educational.
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nirvines88

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Re: A/C Issues - Any ideas?
« Reply #23 on: August 19, 2017, 09:36:41 AM »
Thanks for all the responses.  I'll try to address some of the points brought up by various posters.

1) We do have blinds and curtains installed to try to keep the sun out. 
2) My unit uses the R410A refrigerant.  It's a 9.5 lb system.
3) I keep the house set at 75-77 degrees F, so little variance throughout day.  I had read that big range changes were bad for unit and made it hard to keep up.

Here's what the tech did:
1) Measured pressure or something and found it to be off.  That led to him adding refrigerant.  My system holds about 9.5lbs and it sucked up 4 lbs.  Since it's a closed system, there is obviously a coil leak even though he couldn't pinpoint it.   FYI he charged me $90/lb but only for 3 lbs.  Yes, I'm aware this is highway robbery (last summer a family friend who is a certifed HVAC technician filled me up (before TXV was replaced) for about $30/lb since he buys it direct).
2) Measured temp coming out of my vents - 62 degrees (ideally this would probably be a bit lower if I have unit set at 75).
3) He said that hopefully adding those 4 lbs would likely get me through the summer.  He said if loses refrigerant again I have 3 options (listed below from cheapest to most expensive):

a) Try using a sealant (cost = ~$450.  This would be mixed in with refrigerant.  It's some kind of polymer that reacts to oxygen to seal leaks.  It's risky because typically you want to avoid anything except refrigerant being in your coil.  Some techs think it's a great cheap option to get a few more years out of the unit, but some techs are adamant against using it.

b) Replace the coil (cost = ~$2000).  Tech said a lot of crappy coils were made around the time my unit was installed (2010).  Replacing coil may get another 5-10 years out of unit.  Obviously this one seems the riskiest to me, because the warranty would probably be rather limited and it's expensive.

c) Get a new unit (cost = $6000).  The most expensive option but would come with a longer warranty and perhaps lower electricity bills.  I'm typically a person that wants to try to fix things before replacing them so not a huge fan of this option either.

I'll probably try option a, I figure it's a $500 gamble or so at getting a few more years out of my unit.  If anyone has experience doing options a or b I'd love to hear about it. 

FWIW the tech guy who came out works for a company that doesn't do new unit installs, so I didn't have that typical conflict of interest like I've had with techs in the past (most techs from shady companies are quick to recommend installing a new unit).  He said he would probably try the sealant thing (option a) but his company would profit the most from option b.
« Last Edit: August 19, 2017, 09:39:34 AM by nirvines88 »

bobechs

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Re: A/C Issues - Any ideas?
« Reply #24 on: August 19, 2017, 11:53:41 AM »
Wasn't Elvis buried out in the back yard of his house?

How was that arranged?

fiStressRelief

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Re: A/C Issues - Any ideas?
« Reply #25 on: August 19, 2017, 01:46:25 PM »
Thanks for the update OP. Here is what I would do if I was in your shoes, which I was not too long ago.

- Buy a basic point and shoot thermometer.
- Take a baseline reading now that it blowing cold.
- Repeat each week and record
- Work out a deal with the family friend to check at the beginning of next cooling season or when your measurements show issues.
- Delay replacement as long as you can get through an entire cooling season.
- Work to get the cost down on the r410a. You can buy on 25lbs on eBay for $150.  See if friend will take a flat charge if you supply the refrigerant.

This approach got me through 3-4 years. Once I couldn't make it through a whole season, I ended up replacing the coil with an all aluminum one for $1600.

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ChpBstrd

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Re: A/C Issues - Any ideas?
« Reply #26 on: September 13, 2017, 03:58:33 PM »
j-rod, I will say, I really appreciated your input. I don't know enough to tell my own left foot from an AC unit, but it was still a very interesting read, and I like to think it chipped away a tiny bit more of my HVAC ignorance. Honestly, even seeing the debate itself was quite educational.

Seconded...

EricEng

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Re: A/C Issues - Any ideas?
« Reply #27 on: September 14, 2017, 11:39:44 AM »
I give up... I will sell my tools, truck, and company. I'll also turn back in my PE and stop ripping people off. I will also notify ASHRAE, ACCA, Trane, Carrier and Honeywell that we are all idiots and we have wasted our lives and careers. All of those data logging control systems that were installed are woefully wrong. EricEng has solved the crime and we are all guilty. Everyone needs to go home and reap the savings. I'm done with this bullshit. I'm going back to being a lurker on the site.
I'm sorry you took my disagreement personal, but your reaction is immature and uncalled for.  I presented a logic based rebuttal with supporting explanation based on scientific principals.

Like I said prior, having lots of experience working on equipment and running a successful business do not require a perfect understanding of the underlying science of the field.  Many myths and misconceptions are prevalent in all industries and have persisted for decades. It doesn't mean your work is bad or invalid, far from it.

I'm glad the OP was able to resolve his problem for now.  Getting 62 out at the vents should help a lot.  I can not advise which of those solutions would be best long term, that is an area Capt j-rod would have the most experience and knowledge.

acroy

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Re: A/C Issues - Any ideas?
« Reply #28 on: September 14, 2017, 12:25:23 PM »
I give up... I will sell my tools, truck, and company. ..... I'm going back to being a lurker on the site.

Don't leave us!

I (and I'm sure many others) appreciated the input and can recognize an expert when one speaks. damn the torpedos.
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Kroaler

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Re: A/C Issues - Any ideas?
« Reply #29 on: September 21, 2017, 04:48:03 PM »
I give up... I will sell my tools, truck, and company. I'll also turn back in my PE and stop ripping people off. I will also notify ASHRAE, ACCA, Trane, Carrier and Honeywell that we are all idiots and we have wasted our lives and careers. All of those data logging control systems that were installed are woefully wrong. EricEng has solved the crime and we are all guilty. Everyone needs to go home and reap the savings. I'm done with this bullshit. I'm going back to being a lurker on the site.

Too bad your not in my area.   You see I got this problem  and about 5 techs have looked into it and none of them have answers.    What I need is someone to come out, and Do a manual J and Manual D and see if my system is capable then move on to other stuff untill somebody figures out why my house gets so hot..

I swear so many of these guys DO NOT understand the science behind it... its infuriating...

BTDretire

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Re: A/C Issues - Any ideas?
« Reply #30 on: September 26, 2017, 03:40:36 PM »

2) Measured temp coming out of my vents - 62 degrees (ideally this would probably be a bit lower if I have unit set at 75).

Where you set the thermostat doesn't change the output temperature of the air from the vents. The thing that alters the vent air temperature is the temp of the input air. The hotter the input air the hotter the output air, as with the cooler input, cooler output. There is just a differential temp between input and output. But, yes indirectly where you set the thermstat will affect output temp, but only after the house has reached the lower temperature, not just because you put the thermostat on any certain temperature.
To wordy but I hope I made the point.
Quote

a) Try using a sealant (cost = ~$450.  This would be mixed in with refrigerant.  It's some kind of polymer that reacts to oxygen to seal leaks.  It's risky because typically you want to avoid anything except refrigerant being in your coil.  Some techs think it's a great cheap option to get a few more years out of the unit, but some techs are adamant against using it.

I had a large walk in freezer that was not freezing properly, I had a company come out, they could not find anything wrong. So they added a leak detector to the coolent and charged my $50. No complaint about the cost of the service call, but it still didn't work.
  I went inside and was looking at the evaporator coil and noticed it was all iced up. I made an a increase in the defrost time cycle and never had another problem.
The tech should have seen it!


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