OT- A/C low on freon?

GregSY · Jul 18, 2018

OK...house is 4 years old, Goodman central A/C.

Problem #1
The unit is cooling the house...but not well. The temp drop in the air at the outlet vent is only about 8 degrees F via thermometer.

The outside unit seems to be working properly. The fan is spinning and the compressor is pulling around 8 amps. The big copper pipe is not cold though... only 5-10 degrees colder than ambient. Usually it would be sweating and cold.

If I turn the AC off for a while then turn it back on, it will show an air temp drop of 15 degrees or more - but it quickly backs off and settles out at the 8 degree drop. It's like it is on its way to a 20+ degree drop then something tells it to back off before it can ever get there.

Problem #2
The drain line is another issue which I can't see how is related to the air temp drop....I verified the normal drain line is draining but the drip tray still shows water and the backup drain is also dripping a little. It's like both drains are sharing the duty. What is odd is that the corner of the coil cabinet, right by the normal drain, is leaking water, as if there is a fault in the internal drain pan that allows the water to leak out rather than going into the drain pipe.

Problem #3
Even though the normal drain (which drains into the bathroom sink P-trap below) is working, it looks like they plumbed it below the level of the P-trap. It's hard to take a good pic of this but in any case...the bottom of the drain line is below the P-trap. Shouldn't it be above the P-trap?

thermite · Jul 18, 2018

GregSY said:
OK...house is 4 years old, Goodman central A/C.

Problem #1
The unit is cooling the house...but not well. The temp drop in the air at the outlet vent is only about 8 degrees F via thermometer.

The outside unit seems to be working properly. The fan is spinning and the compressor is pulling around 8 amps. The big copper pipe is not cold though... only 5-10 degrees colder than ambient. Usually it would be sweating and cold.

If I turn the AC off for a while then turn it back on, it will show an air temp drop of 15 degrees or more - but it quickly backs off and settles out at the 8 degree drop. It's like it is on its way to a 20+ degree drop then something tells it to back off before it can ever get there.

Problem #2
The drain line is another issue which I can't see how is related to the air temp drop....I verified the normal drain line is draining but the drip tray still shows water and the backup drain is also dripping a little. It's like both drains are sharing the duty. What is odd is that the corner of the coil cabinet, right by the normal drain, is leaking water, as if there is a fault in the internal drain pan that allows the water to leak out rather than going into the drain pipe.

Problem #3
Even though the normal drain (which drains into the bathroom sink P-trap below) is working, it looks like they plumbed it below the level of the P-trap. It's hard to take a good pic of this but in any case...the bottom of the drain line is below the P-trap. Shouldn't it be above the P-trap?

Have you cleaned your "evaporator" side slant-coil or "A" coil in the air-handler lately? One presumes you HAVE kept the filters changed, etc.

Otherwise, yah. Sounds like a leak.

Have a sight-glass / moisture indicator installed when you get it fixed (and have the new dryer put in).

It isn't the be-all-end-all for monitoring, but it does help to be able to see if you have refrigerant fluid flowing, fluid flowing with bubbles, or NO fluid flowing at all when it should be.

A year's - or even part of a single season of early-warning can save you the price of a new compressor & labour. Or at least let you BUDGET for it.. (my case, at present..)

GregSY · Jul 18, 2018

I haven't done any cleaning but it all looks very clean...at least the parts I can see. Filters have been maintained. This unit is a bit weird to me as it has a big filter on the outlet of the fan. C

Scottl · Jul 18, 2018

Not meaning to insult your abilities but it might be worth a service visit from a pro. They not only have the experience but also the specialized tools. I do my own auto A/C charge but they're pretty simple compared to a whole house unit.

thermite · Jul 18, 2018

GregSY said:
I haven't done any cleaning but it all looks very clean...at least the parts I can see. Filters have been maintained. This unit is a bit weird to me as it has a big filter on the outlet of the fan. C

"Outlet" side of an air-handler used to be where certain types of humidifiers or even electrostatic precips were placed.

Dumb, otherwise, especially if no INLET filter is present, as the primary task for the filter is to prevent clogging of the evap coil fins, not reduce dust on the furniture.

Human lungs are waaay better at self-cleaning than those usually WET fins can ever be.

A 4-year-old residence, HEPA-grade inlet filters being common as housefly-poop these days, plus the use of white-bread Goodman gear sounds more like a corner-cutting developer used marginal krews and got monkey-work out of sheer ignorance.

Best to get a professional eyeball on the whole system, not just the refrigerant levels.

GregSY · Jul 18, 2018

Yes...I've always considered outlet filter dumb for that very reason.

I'm not against having an AC guy come in (I won't use the term 'professional' as I think very few of those exist). I just wanted to check the high points before I did so. But I think that is the next step.

I also noticed there is no P-trap up in the attic on the drain, yet most online references indicate there should be one.

To my credit, I'll note that I already fixed about 3 other things the 'professional' installers of 4 years back half-assed. Plus, the factory Goodman insulation that sits above the blower had come un-adhered and fallen directly atop the inlet of the blower, causing it to suck all the air from the underside, past the motor. I glued that back and plan to wire-mesh it in place.

Bobw · Jul 18, 2018

Scottl said:
Not meaning to insult your abilities but it might be worth a service visit from a pro. They not only have the experience but also the specialized tools. I do my own auto A/C charge but they're pretty simple compared to a whole house unit.

Last summer I get a call from the better half that the AC isn't working.. So I tell her that I don't know a whole
heck of a lot about them, but I grab my multimeter and head on home..

Apparently Cooler, or hotter as the case may be, heads wised up while I was driving and called a professional.

The professional was only a few streets over when he got the call, so he got to the house about the same time
I did.. He pulls out his little toys, tells me to run in and turn it on.... Then TURN IT OFF!!!!!!
15 minutes later we were back up and running.. $120 for the service call, and $120 for a new start cap for the
fan...

It was worth every penny. My old lady would have killed me without the AC, it was one of those 106 degree days.

I'm sure I would have figured it out eventually, but who knows how long it would have taken, or how much money
I would have thrown at it while trying to figure it all out.. As soon as the professional saw what was happening,
he knew exactly where to look, tested the cap, and tossed in a new one.

Sometimes its just best to call in the professional that knows what they are doing, and I'm 100% for doing
things myself, I don't like people touching my stuff, but the house AC, I'm just fine with a professional..

thermite · Jul 18, 2018

GregSY said:
I'm not against having an AC guy come in (I won't use the term 'professional' as I think very few of those exist). I just wanted to check the high points before I did so. But I think that is the next step.

Seems you have a handle on it.

Those who do higher-end systems, especially "zoned" ones, and Lenox and other allegedly-"Cadillac" grade brands, are accustomed to doing surveys to prepare their ordinary quotations. The tools and info they use is all online, too.

I had "the training" at taxpayer-expense (cryogenics, Ft Belvoir, then 'nam), so engineered my own rig for lowest operating costs.

R22, "starved charge", massive 5T rated all-copper outdoor condenser with 2 ton Bristol Recip, 3T rated "A" coil in a 4T rated air-handler. Net-net about 2.5 T, actual, but only 8 A running load and around $12/month to run.

There's now - finally - at least one Weasel-piss blend that can match R22 for both ease of flow and thermal-transfer efficiency, but it is even more flammable than the other wannabees.

Still have 12 lbs or so left of "virgin" R22 from back when I installed it, but I surely wish I had put more R22 aside when I could still get it for only $50/25 lb jug, not $700 or so.

Commercial/Industrial HVAC & refrigeration folk still deal with R22 systems.

Residential "box tick" and ready-made component "kit builder" guys would only want to rip it out and convert to the crappy stuff, don't have the Engineering understanding, are no use to me.

Tony Quiring · Jul 18, 2018

If water is dripping in the wrong place look there.

It means the cold is there.

Another cause is an evaporator ice up blocking air flow and parts near it cold enough to condense nearby water thus dripping out odd place.

Correct current indicates maybe good pressures but wrong water indicates something else.

Good cooling at first then poor cooling supports icing up of evaporator.

Sent from my SAMSUNG-SM-G930A using Tapatalk

GregSY · Jul 18, 2018

Well....the AC guy has come and gone and it was in fact low on freon due to a leaky coil. The coil was frozen up. He added freon and we ran the heater a while to defrost the coil. Now it is cooling well with a drop of about 21 degrees. So...looks like a new coil is in order but luckily, for me, that is the house owner's problem.

I will note that he used 6lbs of freon at....$65/lb! Holy crap. It was the 410 Freon or some such number.

Thanks all!

eKretz · Jul 18, 2018

410a. That's what most of the newer systems use. You can actually buy it without a license, unlike the older ones. I have been charging my own 410a system after getting a service bill like yours once for a simple charge. Was able to buy a good quality set of gauges, manifold and hoses AND a 20 pound canister of 410a for less than one call. My system has a very slow leak somewhere that two separate service guys failed to find, even with UV fluorescing dye. Every 3rd year I have to top it off with a tiny bit. Still got the same tank of 410a I purchased nearly 10 years ago, it's still probably got 15 of the 20 pounds it started with after 3 top-offs. One of these days the compressor may run out of oil if it's leaking out too, but so far I haven't found any signs of it anywhere, and the unit is 17 years old now, so if it does, oh well.

Did your guy actually FIND the leak? Or did he just blame the coil? Because the unit running for a long time with low refrigerant pressure will freeze the coil too. If the conditions are right (freon low enough to screw up normal operation but not low enough to trip the low pressure switch) the unit will run all day to try to meet the thermostat demand but it won't make any progress because the coil will freeze up.

GregSY · Jul 18, 2018

Yeah..I think the AC company is getting a call tomorrow on the price. I looked it up after he left and I can buy it for $5 pound all day long.

He did use a 'geiger counter' type probe to sweep the coil and it started ticking. But frankly he could have triggered it if he was trying to play tricks.

The AC repair biz is a racket...what bothers me the most is how they have managed to practically legislate themselves a living by making it very hard for the non-AC person to work on the systems.

jmead · Jul 18, 2018

eKretz said:
Did your guy actually FIND the leak? Or did he just blame the coil? Because the unit running for a long time with low refrigerant pressure will freeze the coil too. If the conditions are right (freon low enough to screw up normal operation but not low enough to trip the low pressure switch) the unit will run all day to try to meet the thermostat demand but it won't make any progress because the coil will freeze up.

In TXV systems I usually found that an iced coil or other evap air blockage is what caused the low pressure. Homeowner needs to correct any defrost issues first.

eKretz · Jul 18, 2018

By his previous posts I don't think he has any of those. Sounds like the low pressure is the culprit in this case. If the coil actually is leaking that would explain it. My system did the exact same, coil froze due to low pressure. Only thing I did was wait for the coil to thaw and add refrigerant. Working great for 10 years now, just monitor pressures and temps and top off as needed.

CarbideBob · Jul 19, 2018

GregSY said:
....

The AC repair biz is a racket...what bothers me the most is how they have managed to practically legislate themselves a living by making it very hard for the non-AC person to work on the systems.

I don't think the AC repair guys are any happier with all the legislation than you are.
Don't shoot the messenger.
Bob

thermite · Jul 19, 2018

GregSY said:
Well....the AC guy has come and gone and it was in fact low on freon due to a leaky coil. The coil was frozen up. He added freon and we ran the heater a while to defrost the coil. Now it is cooling well with a drop of about 21 degrees. So...looks like a new coil is in order but luckily, for me, that is the house owner's problem.

I will note that he used 6lbs of freon at....$65/lb! Holy crap. It was the 410 Freon or some such number.

Thanks all!

As big as my oversized coils are and with a 46-foot 5/8" line run, my whole system only wants 9 lbs of R-22. But R22 is a single-component refrigerant.

With the weasel-piss, (it is NOT a "FREON") you have a blend of (at least) two separate components, and they have rather different characteristics. Not good enough to just top them up, because any leak will have favoured loss of one component and left the remainder out of balance.

One must vacuum-pump out the leftovers to a recovery tank, and do a full recharge so the balance is proper. Otherwise, the effectiveness, which is not as good as R22 to begin with, cannot match its design parameters.

That puts more stress on the compressor (Copeland scroll type, almost always, with Goodman), and shortens its life as well as using more power for any given level of cooling.

Presuming one seldom uses white-bread Goodman* parts to do a custom oversize or optimization, or "overbuilt" system as mine intentionally is, 6 lbs could be about right for a full charge.

I'd guess your guy DID evacuate it before refilling, so that is at least a plus.

* Goodman's ship to "the trade" with several labels in the carton. Amana and others. The maker doesn't put the label on. The installer picks whichever brand name he claims to have sold and puts it on.

Perfectly legit. Five or so brands each are owned by the four or five remaining makers who are still in the business and dominate it.

eKretz · Jul 19, 2018

thermite said:
With the weasel-piss, (it is NOT a "FREON") you have a blend of (at least) two separate components, and they have rather different characteristics. Not good enough to just top them up, because any leak will have favoured loss of one component and left the remainder out of balance.

One must vacuum-pump out the leftovers to a recovery tank, and do a full recharge so the balance is proper. Otherwise, the effectiveness, which is not as good as R22 to begin with, cannot match its design parameters.

That puts more stress on the compressor (Copeland scroll type, almost always, with Goodman), and shortens its life as well as using more power for any given level of cooling.

I'd guess your guy DID evacuate it before refilling, so that is at least a plus.

This is true for some refrigerantsr but not true for r410a. Though it is zeotropic, only just. Mostly acts just like an azeotropic mix. Topping off does NOT require evacuation, so long as the system remains under pressure.

GregSY · Jul 19, 2018

The theory is the freon was low due to a leak, which in turn (the low freon) caused the coil to ice up. If there was no leak, I don't know how to explain where the freon went. The AC guy did say the coil was made by one of the worst makers....like a lot of systems I have seen, they buy a Goodman air handler / furnace then team it up with an off-make coil.

Joe Rogers · Jul 19, 2018

I’m surprised the condensation drain does not leak under the sink...based on your photo. And there should be a trap in it somewhere but it does not have to be plumbed below the p trap. If it was and didn’t have its own trap you would get sewer gas pulled into the HVAC coil. Now that would not be sweet.
Joe

wheels17 · Jul 19, 2018

@Car2

Those old GE's are fantastic. It is a shame that they left the business back in the 80s. I have one that is 37 years old. The condenser box is about 2'x2'x2' for a 2300 square foot house. Maintenance consists of cleaning the coils and painting any rust. It continues to keep the house cool. It's running R-22.

It looks like it was designed for homeowner install (I bought the house about 22 years ago), as it indicates on the label that it was precharged, and it has some unusual fittings on the lines.

I could probably get a more efficient unit, but I don't see the payback.

I did have a panic similar to Bobw's this year. Fired it up and the breaker popped. Fortunately, a quick look showed a rodent had been inside the case and knocked the start cap lead off the cap. A pinch on the connector with pliers, push it back on, and a cool house!

OT- A/C low on freon?

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