No condensate from Lennox AC

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Nmnunna32

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Lennox variable speed furnace/ac unit. Compressor is outside home. Evaporator is inside in the basement right above blower fan.

Issue is: on normal use there is no condensate.

I believe AC is cooling home fine. I do not know how efficient though. I set my thermostat to 77 and when AC is on, the temp coming out from coil reads about 55. Return air reads about 74.

I am running factory set option - when thermostat calls, blower runs at 82% speed for 7.5 minutes and after that blower goes to 100% if required until thermostat demand is satisfied. What I observed is most of the time mine turns off after 7.5 minutes. This is the case where there is no condensation. Drain pipe runs to floor drain in basement close to the unit. Once in a while it runs for more than 7.5 minutes and so it goes to 100%. This is the case where I see condensate dripping. This tells me that drain pipe is not clogged.

Is this normal for NOT to have condensate during normal run of the AC? My basement humidity is about 52 (I have a portable dehumidifier in basement). My first floor humidity level from my IAQ stat reads between 55 to 58.

Thanks for reading this long post.
 

Fitter30

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55 - 58 RH is high. Like to see it 50% or below. Take a pic of the air handler and condenser tags so i see if theirs sevice manuals online for proper operation.
 

Nmnunna32

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55 - 58 RH is high. Like to see it 50% or below. Take a pic of the air handler and condenser tags so i see if theirs sevice manuals online for proper operation.
Thanks! Attached tags.
 

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WorthFlorida

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You maybe low on refrigerant and the condensation is freezing on the coil, however, I think you are way over the top on size. The part number is a 5 ton unit and not many homes need that size. If you are over sized the AC is short cycling because it cools down too fast and the thermostat shuts the unit off, therefore, condensate hardly has time to build up and the humidity remains high. There are many reasons why units are oversized when installed and I can get into it with more information. I lived in Algonquin, Illinois and I know those summers day can really be brutal and high humidity.

What is your size home? One or two floors? How old is the unit. Have you ever cleaned the coils and check the drain pan for mold and crud?

Set the thermostat way down like 68 and allow it to run at least 1/2 hour, you'll probably see condensation.
 

Nmnunna32

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Hello WorthFlorida... Thank you for your analysis.
My day time thermostat setting is 77. If I lower to just one degree, I see start seeing condensate drain. But it will stop after couple of cycles after lowering.

I am not 100% sure... But I think this issue started right after my annual maintenance check. Outside condenser coils were cleaned thoroughly by the tech. I noticed there was lot of pollen and debris built up. And the tech checked Freon level and said it is good. But I remember there was a short hissing sound (about a second) when he removed the cap to insert his probes in the valve. But I didn't think that would have caused that much of a leak as it was only for a second or two.

I have a theory... may be the unit was running inefficient due to condenser coil debris before and as a result it used to run longer and that produced condensation. I know... now also it is inefficient because it is short cycling. What do you think?

I am wondering if there are any DIP switch settings that are possible on this unit to make it run longer than 7.5 minutes at 82%....
 

Fitter30

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The little that i found this unit appears to be a 5 ton unit and not variable speed. Lennox really makes it hard to get info if your not a dealer.
 

Nmnunna32

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2 months back during annual maintenance check the tech noted following. Are these numbers ok for the coolant levels?

Checked refrigerant levels [x]
TXV ? [x]
Suction PSI 116
Head PSI 355

Tag on the unit says DESIGN PRESSURE LO=236 HI=446.

I am wondering if these HI LO rating should align with actual readings of Suction and Head PSI....
 

WorthFlorida

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2 months back during annual maintenance check the tech noted following. Are these numbers ok for the coolant levels?

Checked refrigerant levels [x]
TXV ? [x]
Suction PSI 116
Head PSI 355

Tag on the unit says DESIGN PRESSURE LO=236 HI=446.

I am wondering if these HI LO rating should align with actual readings of Suction and Head PSI....

There is a pressure chart vs ambient air temp on a label inside the condenser unit. The little hiss noise when connecting the gauges loses a negligible amount of refrigerant. I'm not very familiar with pressure readings since I never owned a set of gauges, however, as long as you're cooling and the high side pressure is good. The name plate is the max numbers, not necessarily the working pressures since air temp plays a big part. If your thermostat has a humidity set point, lower it. There are no switch settings to reduce short cycling But I haven't found the user manual to how to determine the dip switch settings. I'm sitting at Seattle-Tacoma airport for my flight back to Orlando.
 
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jadnashua

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An a/c unit works best when it needs to run constantly on the hottest design day as it can only dehumidify if the coil is cold and you move enough air over it...each pass will pull a little more moisture out. When only cool for a short period between cycles, it doesn't dehumidify much. YOu can be comfortable at a higher temperature when the air is drier than at a same temp when it is humid.
 
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Is this normal for NOT to have condensate during normal run of the AC? My basement humidity is about 52 (I have a portable dehumidifier in basement). My first floor humidity level from my IAQ stat reads between 55 to 58.
How much water are you getting out of your dehumidifier and how much are you running it?
 

Fitter30

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2 months back during annual maintenance check the tech noted following. Are these numbers ok for the coolant levels?

Checked refrigerant levels [x]
TXV ? [x]
Suction PSI 116
reading would Head PSI 355

Tag on the unit says DESIGN PRESSURE LO=236 HI=446.

I am wondering if these HI LO rating should align with actual readings of Suction and Head PSI....
Hi lo pressures on tag mean nothing they are test pressures. 116 lbs suction 39.5°f looks good. If you have a txv subcooling should be 9-10° you don't have that reading. That is liquid line temp minus liquid pressure 355 /107.5° txv takes at least 20 minutes to start to settle down from hunting.
Other reading would wants temp at filter and 18" from evap coil with pocket thermometer. 18 - 24° 20° is very good. At the highest summer temp does the unit cycle?
 
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Nmnunna32

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How much water are you getting out of your dehumidifier and how much are you running it?
I am running 70pint dehumidifier continuously in my basement. It drains to sump pit. If I let the bucket collect water I would say i probably have to empty it couple of times a day. I set my humidistat to 50. Occasionally it reaches 50 and the unit shuts down. But I want to say the unit runs 90% of the time.

But I don't think this is the issue. I am posting my latest observation regarding blower fan AUTO vs ON setting...
 

Nmnunna32

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Hi lo pressures on tag mean nothing they are test pressures. 116 lbs suction 39.5°f looks good. If you have a txv subcooling should be 9-10° you don't have that reading. That is liquid line temp minus liquid pressure 355 /107.5° txv takes at least 20 minutes to start to settle down from hunting.
Other reading would wants temp at filter and 18" from evap coil with pocket thermometer. 18 - 24° 20° is very good. At the highest summer temp does the unit cycle?
Thanks. At the highest summer temp I would say my ac cycles 3 to 4 times an hour
 

Nmnunna32

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Thanks. At the highest summer temp I would say my ac cycles 3 to 4 times an hour

This is my latest observation....
Blower fan has been set to ON (as opposed to AUTO) all along. When the AC is not operating blower runs at 783rpm (I think this is 450cfm) continuously. This is how it has been.

Yesterday for the first time, I changed this setting to AUTO. Before change, home humidity level was 55% and after about 5 hours of change humidity dropped to 48%. STARTED SEEING CONDENSATE RIGHT AFTER THE CHANGE AND CONTINOUSLY WHILE AC IS WORKING. IN BETWEEN CYCLES THERE IS DROP BY DROP DRIP.

This tells me that when the blower setting was ON, whatever condensation that is left in the coil was being distributed back into the home and is the reason for high humidity.

This is just my observation. I am not thrilled to leave blower AUTO because my blower is recommended to run continuously to minimize wear and tear on blower.
 

WorthFlorida

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This tells me that when the blower setting was ON, whatever condensation that is left in the coil was being distributed back into the home and is the reason for high humidity................
There is alway condensation left behind in the drip pan since it is nearly flat with just a slight tilt since most coil assemblies are assemble in air handlers that can be installed vertically or horizontal. Occasionally you need to check the drip pan for mold and crud that does built up. Coil cleaner will help and at times you may need to spray water over the coils and pour warm water into the drip pan to flush out the crud.

I asked a few days ago the approximate square footage of your home. The old school of thought was 1 ton per 500 square feet. That would be 5 ton for a 2500 square foot home. Now with more efficient windows, insulation, better SEER rating for AC units, a 3.5 ton is the norm for the same size home provided your duct work is large enough. As many of us suggested earlier, you AC unit is over sized for the home, therefore, the AC will run less and remove little humidity. Cycling the blower motor barely does not shorten the life the blower motors. As it happened to me, they'll fail in the first year or last the life of the unit, 10-20 years. Do realize the outside condenser fan only runs when the compressor runs.
 

Nmnunna32

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There is alway condensation left behind in the drip pan since it is nearly flat with just a slight tilt since most coil assemblies are assemble in air handlers that can be installed vertically or horizontal. Occasionally you need to check the drip pan for mold and crud that does built up. Coil cleaner will help and at times you may need to spray water over the coils and pour warm water into the drip pan to flush out the crud.

I asked a few days ago the approximate square footage of your home. The old school of thought was 1 ton per 500 square feet. That would be 5 ton for a 2500 square foot home. Now with more efficient windows, insulation, better SEER rating for AC units, a 3.5 ton is the norm for the same size home provided your duct work is large enough. As many of us suggested earlier, you AC unit is over sized for the home, therefore, the AC will run less and remove little humidity. Cycling the blower motor barely does not shorten the life the blower motors. As it happened to me, they'll fail in the first year or last the life of the unit, 10-20 years. Do realize the outside condenser fan only runs when the compressor runs.

Thanks. My home is about 3400sft. 9foot ceilings first floor. Cathedral ceilings second floor.

I agree. I have a feeling that dripping is cruddy. It may be acting like a sponge. With blower fan continuously ON it is pushing moisture back into the house. My evaporator coil is behind power humidifier. I removed humidifier and using flashlight I was able to see one side of coil. It appears to be clean. The pipes inside the fins are shiny. However, I could not see the pan at all. I have no access. All the other sides of the cabinet are closed. I have to find a way to check the pan.
 

Fitter30

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Never have i heard that explanation of running a blower on verses auto. You are correct when running the blower full time the cooling is satisfied coil does put RH back into the space till it dries out. Also filtration is better. Downside blower being variable speed running 24/7 cost of the electric, in winter cold drafts and with a humidifier they don't put much RH in the air when furnace isn't calling for heat. RH is a little different raise the temp just degree or two without changing vapor content it drops %.
 

Nmnunna32

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Never have i heard that explanation of running a blower on verses auto. You are correct when running the blower full time the cooling is satisfied coil does put RH back into the space till it dries out. Also filtration is better. Downside blower being variable speed running 24/7 cost of the electric, in winter cold drafts and with a humidifier they don't put much RH in the air when furnace isn't calling for heat. RH is a little different raise the temp just degree or two without changing vapor content it drops %.

Do you recommend blower setting AUTO irrespective of HEAT or COOL? 10 years ago when this equipment was installed, my installer told me it is better to run blower ON all the time because it mixes well and eliminate cold/warm spots. And also frequent start/stop in AUTO mode is bad for the blower.

I will be happy to leave it in AUTO for both summer and winter if it doesn't hurt the equipment. I already have hot/cold spots so I know ON mode did not help me in that respect.
 

jadnashua

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My blower has been on since about 1987 and still going. It's a variable speed fan (16-speeds), so when it's not calling for heat or cool, it's barely on, but enough to keep the air from stratifying.

Under maximum design day, ideally, the a/c would run continuously. As has been mentioned, the a/c only dehumidifies when it is running, and you will be more comfortable at a slightly higher temperature, if the humidity is lower on a day where things may get super hot outside.

Trane had an add way back where they compared two of their identical compressor units, one hooked up to their variable speed air handler, and the other with a fixed speed one. Over the course of a summer, they measured enough extra water extracted in the variable speed unit to fill a typical back-yard swimming pool. Running slow at the start up had the air moving over the coil slower, extracting more moisture. If required, it would speed up, and then ramp down at the end. That also helped in the winter as it gave the heat exchanger a chance to warm up before it started to blow faster.
 
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