A/C is cooling but humidity is high

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  #1  
Old 06-08-04, 12:14 PM
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A/C is cooling but humidity is high

Hi all,

I have 2 compressors, one for upstairs one for downstairs. Downstairs is fine and keeps humidity at around 46-48%. Upstairs keeps the TEMP where I set the thermosat but it feels warmer because humidity is 70+%. Drain is working fine (can see the water dripping out) and nothing is overflowing into the catch pan (condenser is in the attic).

What gives?

Thanks,
Jim
 
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  #2  
Old 06-08-04, 12:41 PM
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Jim,

Humidity is mostly controlled by the capacity and run time of the a/c unit.
As long is the unit is maintained and working properly you would likely find that the unit might be slightly oversized.

Just make a note of how long the upstairs unit runs as compared to the main floor unit.
 
  #3  
Old 06-08-04, 01:23 PM
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Greg,

Thanks for the reply. I'm pretty sure I haven't "properly" maintained the unit because in 5 years I haven't done anything to it. It's never been this humid upstairs before. Also, every year when I turn it on it stinks - I'm thinking water is accumulating somewhere.

The downstairs unit definitely runs a lot more often since the sun beats through the living room (where the thermostat is) windows a good chunk of the afternoon.

It's 93 degrees outside today. I turned the fan to contant on and the humidity has dropped substantially.

Thanks,
Jim
 
  #4  
Old 06-08-04, 03:29 PM
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have your systems serviced. a good check of all important factors will save you in the long run.

refrigerant
amp draw of compressor
coils (in and out) insp and or cleaning
drain cleaned
evap blower motor insp/clean

ever drive your car 5 years without service?
 
  #5  
Old 06-08-04, 04:15 PM
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For the cost just some cheap stick awning. Hang them on the edge of the fascia board on the overhang there . To cover the windows in the daytime could help a lot.


ED
 
  #6  
Old 06-08-04, 04:48 PM
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Thanks all for your replies.

I called the guy that installed the HVAC when the house was built to take a look at it. I do lots of things myself, but this does not appear to be something that I should take on.

As far as the sun coming in the living room, I think I'm going to go with blinds. There are shades now but they let a lot of light through.

Jim
 
  #7  
Old 06-08-04, 05:09 PM
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Wink

The shades hanging out side help more than the ones inside the window. Down here they have a Bahamas shutters. They go at a angle from the top to out at the bottom of the window so you can look right out from inside but the sun dont hit the windows.Just something to kick around .


ED
 
  #8  
Old 05-30-06, 02:32 PM
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Believe it or not, I am still having this problem with my A/C. I know this thread is 2 years old, but I'm still looking for advice. I had the HVAC guy come out and check the system. He says there's nothing wrong with it. I've been in the house since 1999 and the a/c did function properly at one point in time.

The problem, again, is that the humidity upstairs is at least 10% higher than downstairs. Upstairs it's 60%+ which is not right - the A/C should be drawing a lot more moisture out of the air. The more the a/c runs (like when it's very hot out) the more humid the air gets. The guy says it's draining properly. I also get a smell when I turn it on after the winter or if it hasn't run for a week or so.

Is there anything I can check myself? I can see the water dripping out of the drain outside.....

Thanks,
Jim
 
  #9  
Old 05-30-06, 02:38 PM
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slow down the blower.
 
  #10  
Old 05-30-06, 03:31 PM
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Originally Posted by tinner73
slow down the blower.
That makes sense, but the thing is that it worked right at one point in time. Plus it can barely keep up with the blower the way it is. When the sun swings around to the front of the house it runs constantly.

Thanks for the reply!

Jim
 
  #11  
Old 05-30-06, 06:51 PM
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With you saying you get a smell, It sounds like a dirty coil.

Even if the coil looks clean it could be dirty on the inside.
It could also be dirty on the under side.

Thats the indoor part.

Now for the outdoor condensing unit.

The coils must be cleaned from the inside and out side of the unit.

The unit may have to be taken apart a bit to have that done.
 
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Old 05-30-06, 08:51 PM
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Your problem could be easily solved with some very basic refrigeration troubleshooting.
A set of guages, a clamp on ammeter and a thermometer, properly used will quickly tell you what is going on.
Something as simple as bad valves in the compressor could cause the symptoms you are experiencing.
If you have electric heat maybe an element has shorted to the frame and is partially heating.

No disrespect to the person you called but if you have a problem then there is something wrong with your system.

If we were there we could diagnose this for you but without getting our hands dirty we could be speculating for another two years.
I would suggest you either send one of us an airline ticket or call a different service company.
 
  #13  
Old 05-31-06, 02:50 AM
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Originally Posted by GregH
I would suggest you either send one of us an airline ticket or call a different service company.
I'm going to check the coils myself. If they're not obviously dirty then I'll call another company. I'm not sure what this other guy did but he wasn't here very long.

Thanks all,
Jim
 
  #14  
Old 05-31-06, 09:24 AM
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Wink

Have you tried to slow the upstairs blower down Like we have all said

ED
 
  #15  
Old 05-31-06, 04:01 PM
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Originally Posted by Ed Imeduc
Have you tried to slow the upstairs blower down Like we have all said

ED
You haven't 'all' said to slow the blower. Actually prior to your post only one other person suggested that. Since the upstairs unit worked fine for 5 years and suddenly started behaving this way I'm going to pursue other avenues before slowing the blower down. I'm assuming slowing the blower is a way to compensate for an over-sized unit, which hasn't been the problem to date.

I'm not ungrateful for the suggestions, but I don't understand the logic behind that particular suggestion.

Jim
 
  #16  
Old 05-31-06, 04:57 PM
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The new Trane units we have that have a V/S blower in the units have a humidity control set up. Where you can set the control that when the humidity gets to high or over what you set the control for. The blower will slow down till the humidity gets back down to where you set the control.
5 years and it worked. Is the blower coil clean ???? TXV valve OK??

ED
 
  #17  
Old 05-31-06, 06:18 PM
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Originally Posted by Ed Imeduc
5 years and it worked. Is the blower coil clean ???? TXV valve OK??

ED
Yeah, this is a Lennox unit that is 7 years old. I bought the house new in 1999. I started having the humidity problem in 2004, which is also when I first posted here.

The more the a/c runs the higher the humidity gets. At night, when the sun is down, the humidity drops to about 5% higher than the downstairs. Just before dusk, when the sun is shining full blast at the front of the house I get a 10-12% difference in humidity up vs. down. The basement and first floor settle in the high-40s. The upstairs gets to 60% or more. Very strange.

I'm not sure the blower coils are clean. I trusted that the guy I paid to come look at the thing did that. I need to take a look myself. Evidently, like most things in life in order to do it right you have to do it yourself. I'll let y'all know what I find, if anything.

Jim
 
  #18  
Old 05-31-06, 06:27 PM
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when you slow down the blower the air actually spends more time over the evaporator thus removing more moisture.
 
  #19  
Old 05-31-06, 06:35 PM
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Originally Posted by tinner73
when you slow down the blower the air actually spends more time over the evaporator thus removing more moisture.
That's what I figured, but why would the air need to spend more time over the evaporator now when it didn't have to spend as much time over the evaporator a few years ago? I'm thinking that it's either dirty or that the evaporator isn't as cold as it should be (low charge?).

Thanks,
Jim
 
  #20  
Old 06-01-06, 04:35 AM
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If the unit is in the attic have you checked all the returns up there to make sure one of them haven't came loose and is pulling hot humid air through the unit ??
 
  #21  
Old 06-01-06, 05:17 AM
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Originally Posted by mattison
If the unit is in the attic have you checked all the returns up there to make sure one of them haven't came loose and is pulling hot humid air through the unit ??
It is in the attic. I have not checked that - that's a good possibility.

Thanks,
Jim
 
  #22  
Old 06-01-06, 08:11 AM
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Okay. It's not sucking air from the attic and the evaporator and condenser coils look squeaky clean. I'm assuming that the pressure checks the guy did 2 years ago were accurate and I don't have a low refrigerant situation. I guess I need to slow the blower down? How is this done?

The only reason why the system might have a problem now versus when it was new could be repairs that were made to the furnace a few years ago. The burner was not staying lit as a result of a problem with a pressure switch. Ultimately they determined that the problems was the model of the furnace that I had and the fact that it was mounted horizontally. I was told that they 'gutted' the furnace and replaced all of the innards. I'm not sure if that included the blower motor or not, but if it did I may have a more powerful blower than was originally installed.

Thanks,
Jim
 
  #23  
Old 06-03-06, 11:44 AM
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Originally Posted by Ed Imeduc
The new Trane units we have that have a V/S blower in the units have a humidity control set up. Where you can set the control that when the humidity gets to high or over what you set the control for. The blower will slow down till the humidity gets back down to where you set the control.
5 years and it worked. Is the blower coil clean ???? TXV valve OK??

ED


Ed,
What terminals would one use to activate or use the humidity controls on a Xl14i with a VS blower
Thanks,
 
  #24  
Old 06-04-06, 06:15 AM
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harveje
Ed,
What terminals would one use to activate or use the humidity controls on a Xl14i with a VS blower
Thanks,

Look on the inside of the blower door of the Trane V/S blower .Read note #5 If humidistat is not used.Connect jumper from R to BK for full tonnage airflow in cooling.
So if this is what you have pull the jumper off
R to BK and wire the humidistat from R and back to BK.


ED
 
  #25  
Old 06-04-06, 07:24 AM
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Sorry,
I meant dehumidify, My new T'stat has a dehumidification terminal and I want to use it in conjunction with the VS Trane system. My system is oversized for cooling and the humidity is high, systems runs 5-7 min. off 7-10 min. Dealer is giving me the run around. Do you happen to have a list of terminals and their functions for Tranes VS air handlers mine is a TWE065E
Thanks a mill.
 
  #26  
Old 06-04-06, 12:24 PM
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Check on th blower door for wire lay out. They say humidistat in the schematic . But like it shows for the TWE-E V/S blower pull the jumper off R to BK. As you have R at the tstatTie that BK to the tstat humidity control."check it out first". This should run the blower on slow slowI dont know the stat you have.We just use that small Trane humidity control by the unit. Check out what you have in that stat first. Cut the speed of the blower down some for sure now. Do that on the dip switches. You should have the paper work from the unit to show you.

ED
 
  #27  
Old 06-04-06, 02:53 PM
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Thanks,
I have a Robertshaw 9870i
Terminals
C-24 vac common to B-trane, G fan relay to G trane, Y1 Stg. 1 cool to Y trane, E Emg. heat to W trane, O cool active revs. valve to O trane, R 24 vac to R trane jumped to bk now, W2 Stg 2 heat to W1 or 2 trane and D dehumidity relay to ?????? Trane, I've read the R to BK jumper note but is that for a humidistat or dehumidifier circuit, and I can not find hardly any info on tranes wiring. Thanks for taking the time to help, Dealer said to install fresh air intake to help make system run longer is this true? Since it has not been right from day one should they pay for it? I love the system except for the short cycle and high humidity in house. I run either a dehumidifier or window unit 24-7 to remove excessive humidity.
 
  #28  
Old 06-04-06, 09:45 PM
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First why is the unit over size?????
NO dont take out side air to make it run longer. Thats just more humidity to try and get out of the home.

Since it has not been right from day one should they pay for it? I love the system except for the short cycle and high humidity in house. I run either a dehumidifier or window unit 24-7 to remove excessive humidity.
Id say some one screwed UP big here. I know when we have a bad job. Its on me to fix it at my cost. Get a lawyer here. You sure dont have to stand the cost to try and run all that other stuff to get the humidity out of the home.

I've read the R to BK jumper note but is that for a humidistat or dehumidifier circuit, and I can not find hardly any info on tranes wiring.
The R to BK is what will slow the blower down to take out more humidity.
Slow the blower down now will help you. Also paper work comes with all units. make them give it to you.

ED
 
  #29  
Old 06-22-06, 11:06 AM
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Originally Posted by mattison
If the unit is in the attic have you checked all the returns up there to make sure one of them haven't came loose and is pulling hot humid air through the unit ??
I checked when you first posted this and didn't see anything obvious. However, I think you're onto something.

I'm sitting in my 'office', which is the middle rear bedroom in the house. It gets hot. Hottest room upstairs. I turned on the fan to circulate the cool air from the rest of the upstairs. It got HOTTER, and VERY humid AND I smell 'attic' (woody type smell that I only smell when I'm up there). The compressor came on and is trying to cool things down and has dropped the humidity a bit. It HAS to be getting air from the attic somewhere. There is a little being drawn in from the filter area (not a 100% tight fit between the filter and the opening) but not enough to cause this. I'm going to take a harder look in a few mins.....


EDIT: I went up there. All the returns are fine. The gap between the filter and the sheet metal is about 1/2" the entire width of the plenum. Seems excessive. A lot of air was getting sucked in there. I taped it up with duct tape. I also found a exhaust collar that was knocked off. I re-installed that. Now I have an annoying howling when the system runs - like feedback from a microphone.

Jim
 

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Old 06-22-06, 05:43 PM
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  #31  
Old 06-22-06, 06:50 PM
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Jimmy, you said you had a furnace problem and they might have changed the blower speed at that time. Also, after this long the heat exchanger may have developed a leak. Do you have a CO detector on the same floor? If the heat exchanger splits it could suck some attic air into the air flow.

Your CO detector should signal a leak in the heat exchanger, but only when the heater is on.
 
  #32  
Old 06-22-06, 07:34 PM
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Originally Posted by mdtaylor
Your CO detector should signal a leak in the heat exchanger, but only when the heater is on.
I do have a CO detector but it hasn't gone off with the heat on.

Here's a little more to add to the story. You can't make this stuff up.

The howling noise was freaking out my 5-year old son. He finally fell asleep, as did my wife and 2-year-old daughter. The howling was bugging me. I went up to the attic to see if adjusting some of the vents would help.

I get up there and head for a couple of vents that I had shut off previously. I figured I'd open them up and quiet the howling. I step on a piece of 3/4" pine that was straddling the joists. I've stepped there countless times in the past. This time the pine snaps and down through the ceiling I go. Up to my waist in the celing.

I knew I fell into my son's room since I could hear him screaming in terror. I could also see that the giant pieces of sheetrock had fallen to the floor and not on his bed. He was just panicked over something falling through the ceiling and thus waking him from a dead sleep.

I tried to calm my son by yelling down to him that it was just me and that everything was okay. Naturally this had no effect. I scurried down the attic stairs to try to calm him down before he woke everyone else up. Too late. By this time my wife and daughter were awake and standing in the hall. My son had run out to my wife.

Now at this point my wife thinks that the only problem was that I was walking around in the attic and the noise scared my son. But no. I flipped on the light and brought into focus the true carnage of my fall. There were some angry words exchanged and now everyone is sleeping in my daughter's room.

I am in the proverbial dog house. And have a big drywall repair job, a busted up right knee and a sore left thigh.

I'm going to bed.

Jim
 
  #33  
Old 06-22-06, 07:57 PM
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Is your dog house air conditioned?
 
  #34  
Old 06-23-06, 02:56 AM
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Originally Posted by mdtaylor
Is your dog house air conditioned?
Fortunately yes!

Jim
 
  #35  
Old 06-25-06, 11:21 AM
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Well, I had to cut a 4' x 6.5' section of sheetrock out of the ceiling. My fall took out one of the return grates as well as the smoke detector so I had to cut the new 'rock around those areas. I put the first coat of spackle on it and it's looking much better.

The good news is that between sealing the filter with duct tape and sealing the broken elbow on the exhaust side the humidity is acceptable. Upstairs/downstairs are within 5% of each other. No longer do you go upstairs and feel like it's hotter (the humidity used to hit you like a ton of lead about half-way up the stairs).

Jim
 
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