Any A/C Guru's here?

[cajun 22]

Also check to see if you have the right size filter. I had the same problem and talked to the guy at the A/C supply house. He told me I did not have enough area ( cubic inches ) with the filter for the size of the unit. I increased the size of the filter with a filter grill (closet return unit) and made all the difference in the world. Like having a new unit.

Good Luck

 

[mikeinneworlean]

It may also be worth looking at the duct runs. Good thought on making sure one has not come loose! Examine them to make sure you haven't somehow developed a leak.

Also, (and i thought this was crap when a mechanical engineer told me this until i tried it and it worked) consider suspending your flex duct to take out the bends and curves. Every foot of flex duct slows down the amount of air that will come out the registers, and every 90-degree bend counts as 5 feet of pipe. If you take out the hard bend, and unnecessary bends (up and down over joists, hard turns at the connections, etc), you'll get much better flow. You can get some plastic hanger strapping cheap (think "plastic" band iron) and after that all it takes is sweat and time. Really makes a difference.

i'm not sure who you called for service, but a lot of these "techs" are barely competent to add freon. You might save some energy money long term by calling in somebody with some better experience (brister stephens, etc) rather than a guy who advertises AC, Plumbing, an electrical work on the same truck.

 

[Yrdawg]

Also check to see if you have the right size filter. I had the same problem and talked to the guy at the A/C supply house. He told me I did not have enough area ( cubic inches ) with the filter for the size of the unit. I increased the size of the filter with a filter grill (closet return unit) and made all the difference in the world. Like having a new unit.

Good Luck

Return is one of the most important values in a/c, if the system can't move the proper amount of air it can't cool properly or be diagnosed properly.

Look for 0.0 in" wc negative air pressure in your return chase, settle if you have to for as high as .25 in" wc..over 25 is just NOT gonna work, if you find a service company that can discuss air pressure and flow intelligently you have found a rarity. Untold number of " unsolvable " problems have been solved with air flow diagnostics... but the test equipment isn't cheap and very few service techs even know how to read results or make corrections.

Typical residential a/c operates at 5.0 in w/c total external static pressure, the less energy used in sucking air in the more energy is used in the actual distrubition of conditioned air. ( this is a good thing )

Once again...anyone looking for an a/c service company should ask lots of questions, get info from BBB or whoever can tell you something about who you are hiring. A/C companies are still pretty much wild west, not much regulation, not near what is needed so B Careful

A good place for self help is HVAC-Talk.com, some of the tiers are paid but they aren't much considering what you get. IIRC general info and tips for HO's is still free.

 

[Suburbazine]

If it's a decade old and having trouble moving air, I'll put my bets on the fan being bad or clogged. Also, a slow fan will cause the evaporator to freeze over.

When you take the side panel off and run the fan, does it kick over quickly or slowly spin up to speed? Also, does the fan capacitor measure as good? Is there good airflow at the unit with the panel off? Is the intake filter at the wall/ceiling clogged?

Since you're out of Baton Rouge, I recommend speaking with 1-Hour A/C and getting them to check your system out. If adding freon didn't help, then that was just a feel-good gesture that probably overpressurized the system.

Probably the fastest way to check if the system is operating properly is to feel the air blowing out of the condenser. It should be noticeably warmer than ambient. If it is the same as ambient, then you have a heat exchange problem.

 

[I_FLY_LOW]

Oh, 1 more thing. Check your blower to make sure the blades are not caked up with dust/ dirt. This greatly reduces the amount of air it will move. if you clean it though, be careful and if it vibrates and makes noise after cleaning (somewhat common), be prepared to replace it.

Is replacement a big deal to do?
Maybe I should just plan for that, if it's not really expensive, given it's age, vs. pull it all apart, clean it, put it back together only for it to wind up needing to be replaced..

 

[I_FLY_LOW]

I may have missed it. You indicate the AC catches up at night. Blinds and/or curtains over the windows in the heat of the day will make a dramatic difference. The extra insulation on poor windows and reflected sunlight will improve the air. All of the info from the techs looks good. If the ducts are flexible and in the attic, they may be squeezed off with a box(Christmas decorations). Check them for the obvious obstructions. Good luck.

I have curtains over all the windows.
I figure 90% of my warming problem is eminating from the attic.
I do realize, how much little leaks here and there can easily add up the ineffeciency factor.
The house has a long way to go, in regards to being effecient.
It's an older, pier and beam home, that the previous owner insulated the floor, fairly well, but needs attention, now.
The attic has some insulation, but is basically dead.
That's on my list of things to do as well.
Windows, are single pane, for the most part, some larger than others, but for the most part generally the same size.
2 windows per BR, (X2) 2 larger windows and 2 glass filled doors, in the LR, one smaller window in the kitchen, plus another glass gilled door, and a BR sized window in the wash room.
I guess what my main deal is, when I visit my firends, plus within other houses I've owned, you can walk around, and stand under a register, ans FEEL the cool air blowing on you.
My house, you have to stick your hand right next to the registers to feel anything.
It's trying, but it's just not getting it...
Also, I use ceiling fans to try and move the cool air about, but there's not enough cool air to really move, at this point...

 

[I_FLY_LOW]

Looking at your Evap coil...in the inside unit. Is the system Gas or Electric or Heat Pump ?? HP or electric Heat , the coil will be visible from the air entering side of the unit, usually easy to see. Ck for dirty on the entering side of the coil. In some cases the coil on gas heat units can be seen by pulling the circulation blower out and looking up through the heat tubes. ( most times this will work )

As for cleaning them in place, good luck, sometimes it will work but many times they need to be removed and acid washed outdoors. Good indicators of dirty would be if there are dirt trails around the filter, closet door jambs, and dirt in the blades of the circulation blower drive wheel.

If dirty it still may not be an indicator of your problem, heat exchange may not be seriously affected by what appears to be dirty evap coil. Takes a tech with some training in refrigeration basics, such as super heat - sub cool calculations also a tech worth his pay will be able to take readings with annanometer and see if you even have an air flow problem.

All the other things are considerations as well, duct disconnected, plenum blow out, ALSO if you have electirc heat or HP there may be some of the heat elements on at same time as cooling. This will cancel out cooling capacity.

So much depends on getting a qualified tech, there are a LOT of a/c guys who are nothing more than check gatherers for a contractor. Look for some kind of certification...NATE is a very good indication that a tech is what he should be.

Louisiana has not arrived at regulation like Texas or some other states who require some kind of proof that the techs know their butt from third base.

It has a propane fueled furnace, and the entire system is in the attic.

Who amongst our inmates here, is in the BR/Gonzales area that fits your description, that would be willing to take this close a look at my setup?
Other than being old, the system seems to work, I think it just need some maintenance to improve it's effeciency.

 

[I_FLY_LOW]

If it's a decade old and having trouble moving air, I'll put my bets on the fan being bad or clogged. Also, a slow fan will cause the evaporator to freeze over.

When you take the side panel off and run the fan, does it kick over quickly or slowly spin up to speed? Also, does the fan capacitor measure as good? Is there good airflow at the unit with the panel off? Is the intake filter at the wall/ceiling clogged?

Since you're out of Baton Rouge, I recommend speaking with 1-Hour A/C and getting them to check your system out. If adding freon didn't help, then that was just a feel-good gesture that probably overpressurized the system.

Probably the fastest way to check if the system is operating properly is to feel the air blowing out of the condenser. It should be noticeably warmer than ambient. If it is the same as ambient, then you have a heat exchange problem.

I haven't pulled it apart as of yet, but just listening to it, it sounds like it kicks on and runs pretty quickly, vs a hum, or something indicating a slow or hindered start.
Haven't done any troubleshooting, electrical.electronics wise, as of yet.

The air is definitely warmer than ambient coming from the condenser.

 

[Yrdawg]

It has a propane fueled furnace, and the entire system is in the attic.

Who amongst our inmates here, is in the BR/Gonzales area that fits your description, that would be willing to take this close a look at my setup?
Other than being old, the system seems to work, I think it just need some maintenance to improve it's effeciency.

Not me bro, I'm on the west side but if I was there I would hook u up just to not let the sharks at you. Sounds like a lot of knowlegable people are willing to help, if theres anything I can do by phone IM me for my #

 

[I_FLY_LOW]

The more I think about this, the more infuriated on the outcome I got...
I called the home warranty folks, and flipped this s*it on them...
Told em after spending my deductable on the last service call, and expressly explaining the symptoms of my problems then, the system still does not have the airflow it should have.
I'm not a licensed A/C tech, and shouldn't have to do the job they get paid to do, and I wanted to have them send someone out that's going to get up there, and work on my system, and resolve the issues...
I wanted the blower inspected, evap coils checked, cleaned as necessary, and ductwork checked for leaks and blockages.

Just for S&G, i set the fan to on, and turned off the A/C, in the event there was some overlooked ice formation, and let it go yesterday, while I was at work. Got home at 5PM, house temp was 91*.. clicked the A/C back on and went out for the evening. Came back around 11:30, house was only down to 87*. Went to bed, got up this morning around 6 AM, temp was only down to 80*... I fear it may not catch back up by tonight.

Thanks for all the insight on what I should be looking for as possible problem areas.
i had some ideas in the back of my mind, but didn't know the terminology, nor where to look.
Thank you all, who contributed info, here.
I'll post up, as soon as I have some resolution.

 

[Yrdawg]

Guessin theres been no one " work " on the system yet...at least I hope not

We do home warranty work, I am not allowed to do anymore b/c I won't write the report as instructed by our owner or the HO / realtor.

That should tell some story

The system dosn't have a leak, it needs the charge adjusted, the coils are not dirty, there are air flow issues...always some story to clear the seller and screw the buyer

 

[I_FLY_LOW]

Picked up a 6k BTU window unit for the BR last night, going shopping for a 12k BTU for the LR, this evening...
Woke up to a 68* BR this morning, the rest of the house cooking at 77*...

 

[edman87k5]

Picked up a 6k BTU window unit for the BR last night, going shopping for a 12k BTU for the LR, this evening...
Woke up to a 68* BR this morning, the rest of the house cooking at 77*...

Now you are doing it right!
If nobody is home during the day, try cranking the central unit way up while gone or setting the timer to come on maybe 30 minutes before you come home if you have such. When you get home, turn on the central and both window units and you should be cool within 30 minutes. Leave the central turned up high mostly and rely on the window units to do most of the cooling. You should be much more comfortable and elec bill should be much lower= win/win.

As a side note, please be certain your wiring (especially if an older home) is up to the task of a 12 unit if you are plugging directly into a wall outlet already there (which you are not really supposed to do). If this is how you are planning to run it, I personally would not leave it on while away from home, but I am picky about elec things running while I am away.

 

[Yrdawg]

Use 230 volt unit's where possible, while 115 's are cheaper to to buy they will imbalance your load and very possibly increase useage, if you do use 115's run them all and use an amp meter to balance your breaker panel

Winder units are IMO some of the most economical ways to cool, use what you need and let the others rest. But only if they aren't running in imbalance and costing money. Thats why I say use 230 v and not worry again about balancing

 

[I_FLY_LOW]

Snagged a 15k btu unit last night...
Geeze, I didn't realize how big this thing is...
I'm not sure if it's going to fit the window, where I want to put it...
Now where did I leave that shoe horn....

I'll check out the circuit layout this weekend.
Thanks for mentioning that.

BTW, original a/c company is coming back out, Monday.
We'll see how this goes.
I'm going to have them check all that you guys suggested, that he should have, on his first visit.
To be continued...

 

[acman]

Looking at your Evap coil...in the inside unit. Is the system Gas or Electric or Heat Pump ?? HP or electric Heat , the coil will be visible from the air entering side of the unit, usually easy to see. Ck for dirty on the entering side of the coil. In some cases the coil on gas heat units can be seen by pulling the circulation blower out and looking up through the heat tubes. ( most times this will work )

As for cleaning them in place, good luck, sometimes it will work but many times they need to be removed and acid washed outdoors. Good indicators of dirty would be if there are dirt trails around the filter, closet door jambs, and dirt in the blades of the circulation blower drive wheel.

If dirty it still may not be an indicator of your problem, heat exchange may not be seriously affected by what appears to be dirty evap coil. Takes a tech with some training in refrigeration basics, such as super heat - sub cool calculations also a tech worth his pay will be able to take readings with annanometer and see if you even have an air flow problem.

All the other things are considerations as well, duct disconnected, plenum blow out, ALSO if you have electirc heat or HP there may be some of the heat elements on at same time as cooling. This will cancel out cooling capacity.

So much depends on getting a qualified tech, there are a LOT of a/c guys who are nothing more than check gatherers for a contractor. Look for some kind of certification...NATE is a very good indication that a tech is what he should be.

Louisiana has not arrived at regulation like Texas or some other states who require some kind of proof that the techs know their butt from third base.

This. Who the company sends to your house to check your system makes all the difference in the world with your A/C. Most techs in my area have no idea the meaning of readings such as superheat, subcool, static pressure, delta T. All of these measurements are extremely important to see the overall condition of your system. If these measurements weren't taken then the tech probably just saw the blue gauge was on 72 and thinks everything is ok ( amazingly this is the rule in most areas of the state, not the exception ). It would really not be possible to accurately diagnose your system without actually being there to see the conditions, and take measurements, but a little info may give more ideas about your problem. Checking the temps of the entering return air and the temps of the leaving supply air from a supply register close to the furnace would be a good start.

 

[diat150]

first thing to determine is if the unit is working properly. you should measure the difference in the temp of the air going into the return and then measure the output at one of the vents. look for around 16-20 degrees difference between the two. if that difference isnt there you need to figure out why. could be that the coils are stopped up, either inside or outside.

if it does have the correct difference id look at your ductwork. make sure that you dont have any leaks or anything.

 

[acman]

first thing to determine is if the unit is working properly. you should measure the difference in the temp of the air going into the return and then measure the output at one of the vents. look for around 16-20 degrees difference between the two. if that difference isnt there you need to figure out why. could be that the coils are stopped up, either inside or outside.

if it does have the correct difference id look at your ductwork. make sure that you dont have any leaks or anything.

The service tech that came to his house should have done this check, but also know what the target delta T for his specific conditions is. Just because its getting 16 degrees diff. doesn't necessarily mean its right for his conditions (outdoor ambient, indoor dry bulb, indoor wet bulb, humidity levels). But generally this is correct. To OP, if your difference is more than 20 degrees, you probably have an airflow restriction whether it be dirty coil, filter, poor duct design or like another poster mentioned a blower wheel that has accumulated a lot of dirt; however, if your blower wheel is that bad your evap is almost certainly clogged up.

 

[bearfutedninja]

one thing to check is make sure your ducts are at least 18 inches from the blower on the plentum. they air needs to create a vortex.