Lennox system not removing enough humidity

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Old 07-15-12, 12:11 PM
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Lennox system not removing enough humidity

I started a thread on this last year.... http://www.doityourself.com/forum/ai...dity-high.html

I wanted to update what was going on. Instead of posting the model#'s I snapped a pic of the tags on both units to ensure I didn't leave anything out. I had someone come by last year that was very reputable and honest, he said the charge was good and likely an airflow issue. He also said the units listed are not usually paired together, while they are compatible on paper, he has never really seen them together.

What was originally inside had a larger footprint and the ducting has been stepped down slightly to accomodate this current air handler. I'm currently running filters in the returns....(1) 20x20 upstairs and (1) 12x12 downstairs.

Currently today it's 92 deg ambient with the heat index of 100, it's the heat of the day and the sun is fully showing it's face. I have the stat set at 71 and fan on AUTO. I'm getting 58 deg at the register near the end of the run, humidity is around 54-55% and there is a slight trickle of water down the drain tube.

Could the fan speed be too high? I have a 3-speed fan and the 3 wires on the motor are orange, black and yellow.
 
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Old 07-15-12, 03:04 PM
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You may want to knock the speed down one notch.
 
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Old 07-16-12, 09:22 AM
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I wanted to update what was going on. Instead of posting the model#'s I snapped a pic of the tags on both units to ensure I didn't leave anything out. I had someone come by last year that was very reputable and honest, he said the charge was good and likely an airflow issue. He also said the units listed are not usually paired together, while they are compatible on paper, he has never really seen them together.

What was originally inside had a larger footprint and the ducting has been stepped down slightly to accommodate this current air handler. I'm currently running filters in the returns....(1) 20x20 upstairs and (1) 12x12 downstairs.

Currently today it's 92 deg ambient with the heat index of 100, it's the heat of the day and the sun is fully showing it's face. I have the stat set at 71 and fan on AUTO. I'm getting 58 deg at the register near the end of the run, humidity is around 54-55% and there is a slight trickle of water down the drain tube. (71F Return air - 58F supply air is only 13F drop normal temp-drop/split with those conditions is around 17F.)

Could the fan speed be too high? I have a 3-speed fan and the 3 wires on the motor are orange, black and yellow.
Blower CFM needs to be checked &, reset if needed, to 350-CFM Per Ton of Cooling. What is the tonnage of your A/C?

If U want me to run a ballpark analysis of how your system is performing in respect to its 'system efficiency ratio' we need at least the following numbers:

Performance Data Collection – Best Time to collect data is Late afternoon around 4:30 pm; also when outdoor temps are around 85; 95; or 105F or, anywhere in between.

1) Helpful, Tonnage of Unit or outdoor condenser model number: ________ Only if you can find it.
2) TXV or, orifice metering device? _______ If you know.
--------
3) Outdoor condenser’s discharge-air-temperature _____
4) Outdoor air temperature: _______
5) Outdoor Condenser air-temp-split ____F
6) Need the percent of humidity - away from Supply-Air outlets ___
7) Indoor Return-Air Temperature ____ Supply-Air Temperature ____

I need all the above data for performance analysis to consider whether it is operating near its normal Rated Range of Performance.
=======================
Performance Data Collection – Best Time, Late afternoon around 4:30 pm
 

Last edited by HVAC RETIRED; 07-16-12 at 09:25 AM. Reason: Left out: with those conditions...
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Old 07-28-12, 05:25 PM
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1) Helpful, Tonnage of Unit or outdoor condenser model number: ________ Only if you can find it.


Inside unit:






Outside unit:





2) TXV or, orifice metering device? __Not sure where to look for this_____ If you know.
--------
3) Outdoor condenser’s discharge-air-temperature __87.4___
4) Outdoor air temperature: _75.8______
5) Outdoor Condenser air-temp-split _11.7___F
6) Need the percent of humidity - away from Supply-Air outlets _72__
7) Indoor Return-Air Temperature _67.8___ Supply-Air Temperature _54.5___


I measured the air temp inside the air handler and just above the coils, temps were 67.8 in and 51.4 out. The readings in red were at the farthest from the coils at the far end of the house and being upstairs, air handler is in the center of the house.

The large line at the outside unit was 59 deg and the small line was 78.6 deg.

The large line at the inside unit was 54.5 deg and the small line was 80 deg.


When I measured the split, I took the temp right at the base of the coils in the center so it differed by a tenth or so from the ambient.


I moved the fan to the lower speed for the AC. We came back from vacation tonight and I could smell a slight musty odor through the house, i'm always keeping an eye out for mold and there is nothing I can find. Sometimes we come home and there is no odor so could possibly be a foundation issue and there is a small amount of moisture wicking inside but there's no areas of moisture in the basement.

Currently it's very humid outside and there has been rain earlier today. Despite the readings at the registers the RH in the house right now is 48%, and that's about as low as the system can get right now. My mom's house is in the mid to high 30% and granted it's a night and day difference.
 
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Old 07-28-12, 08:58 PM
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TXV or, orifice metering device? __Not sure where to look for this_____ If you know.
--------
3) Outdoor condenser’s discharge-air-temperature 87.4
4) Outdoor air temperature: _75.8
5) Outdoor Condenser air-temp-split _11.7-F
6) Need the percent of humidity - away from Supply-Air outlets _72% appears to be vent outlet humidity reading?
7) Indoor Return-Air Temperature _67.8___ Supply-Air Temperature _54.5___ 13.3-F temp-split

I measured the air temp inside the air handler and just above the coils, temps were 67.8 in and 51.4 out.
The readings in red were at the farthest from the coils at the far end of the house and being upstairs, air handler is in the center of the house.

The large line at the outside unit was 59 deg and the small line was 78.6 deg.

The large line at the inside unit was 54.5 deg and the small line was 80 deg.

When I measured the split, I took the temp right at the base of the coils in the center so it differed by a tenth or so from the ambient.

I moved the fan to the lower speed for the AC. We came back from vacation tonight and I could smell a slight musty odor through the house, i'm always keeping an eye out for mold and there is nothing I can find. Sometimes we come home and there is no odor so could possibly be a foundation issue and there is a small amount of moisture wicking inside but there's no areas of moisture in the basement.

Currently it's very humid outside and there has been rain earlier today. Despite the readings at the registers the RH in the house right now is 48%, and that's about as low as the system can get right now. My mom's house is in the mid to high 30% and granted it's a night and day difference.
I'm going to use a simpler data sheet:
1) Helpful; Tonnage & SEER of Unit & outdoor condenser model number: 2-Ton

2) TXV or, orifice metering device? __. Only if U know…

3) Outdoor condenser’s discharge-air-temperature 87.4-F
Subtract Outdoor air temperature: 75.8-F
Outdoor Condenser Air-Temp-Split 11.6-F

4) Need the ‘Indoor’ percent of relative humidity - away from Supply-Air outlets 48% - At outlets 72%

5) Indoor Return-Air Temperature 67.8-F
Subtract Indoor Supply-Air Temperature 54.5-F
Indoor temperature-split 13.3-F

Your % RH from the supply air outlet may not have been accurate; if it was: I ran the enthalpy & it would be delivering only 13,212-Btuh.

At those light load conditions & at 800-CFM it should deliver 20,000-Btuh so with those conditions & WB temp figures it is 6,788-Btuh short or little over halt a ton.


I have a lot of variables in that equation, I even figured the WB at 500' elevation & the enthalpy was figured at sea level; won't make much difference though.

The condenser 87.4-F while the split was at 11.7-F; but that is also a very light load.

The indoor split was only 13.3-F it should be around 18 to 19-F. (I measured the air temp inside the air handler and just above the coils, temps were 67.8 in and 51.4 out); that is 16.4-F. Losing too much in duct system!

For one thing you are running very low indoor temp settings; you should be comfortable at close to 73 to 75-F & 50% RH with some exterior floor fan or ceiling fan air circulation.

It is late & I got to hit the sack & let someone else work the other numbers...
 
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Old 07-29-12, 01:56 AM
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First off, thank you for the help and all the number crunching. Had to get the sis-in-law off to the airport so I will try to add some more info..

Sorry for the misunderstanding of some of the figures..., I was thinking away from the coils as much as possible on the supply, my bad.

It will be warm today as well so I will get some readings closer to the heat of the day. My elevation is roughly 350' and we try to keep the AC at 73 but it's just on the cusp of not being comfortable humidity-wise.

This unit was installed about 10 years ago and replaced the original unit. The original used a larger footprint and there is a reduction in the ductwork above the air handler to match them up. The system uses two return openings, one 20x20 and one 12x12. The return duct while housing both 20x20 and 12x12 opening measures 8x20, the 20x20 is the farthest away and is on the top floor, roughly 17' from the basement floor where the 12x12 is located.

Here's the blower and while the wire tap is hard to see on the right, I have the black AC wire in the #4 slot for LOW speed, this also the 3-speed version.



The temp/RH gauge I'm using is a Fluke 971, not sure of the RH accuracy but the temp is in check with my other probe. Filters are clean and I just recently cleaned the indoor coil but haven't touched the outdoor coils. The filters are the Flanders and have the white cotton-like material, not the 3M Ultra style filters.

I wanted to add that the Lennox tech that came out to assist in the heating portion of this unit, mentioned that he hasn't seen these two units paired together, while compatible on paper they are not often matched up. Someone also mentioned a possible expansion valve being faulty, not sure how to check but wanted to pass that along.

Hope this helps, any more info needed I will do my best to provide, take care.
 
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Old 07-29-12, 07:21 AM
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The temp/RH gauge I'm using is a Fluke 971, not sure of the RH accuracy but the temp is in check with my other probe. Filters are clean and I just recently cleaned the indoor coil but haven't touched the outdoor coils. The filters are the Flanders and have the white cotton-like material, not the 3M Ultra style filters.

I wanted to add that the Lennox tech that came out to assist in the heating portion of this unit, mentioned that he hasn't seen these two units paired together, while compatible on paper they are not often matched up. Someone also mentioned a possible expansion valve being faulty, not sure how to check but wanted to pass that along.

Hope this helps, any more info needed I will do my best to provide, take care.
To perform the enthalpy Btuh numbers, I need the wet bulb temps of both the Supply Air & the Return Air plus a close ballpark of the CFM going through the evaporator coil. I had to convert %humidity to wet bulb temps losing some WB accuracy...

That good Fluke 971 can also provide wet bulb & dew point temps; given time to adjust, its WB temps should be accurate enough; it is great you have that instrument. Lowest price I've seen is 220, usually 265 bucks.

Well, that does appear to be the correct speed tap to use. However, the CFM needs to be measured two ways.

Not pertinent here however, where pertinent; way too low an airflow won't allow it to keep up with higher temp & much higher grains of moisture per lb of that much warmer infiltration air.


Are those filter grille sizes or, just RA grille sizes?
 

Last edited by HVAC RETIRED; 07-29-12 at 07:53 AM. Reason: Clarity...
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Old 07-29-12, 08:29 AM
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The WB temp under the coils is 62 deg and directly above is 48 deg, WB temp in the rooms away from the supply is 59.5 deg.

Air temp outside of the condenser coil is 76.2 deg and discharge temp is 88, this is ambient temp not WB.

Not sure of the CFM but that meter is next on the B-day list.

The small line temp on the small outside line before the dryer/filter is about 2 tenths warmer nearest the compressor compared to after the dryer.
 
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Old 07-29-12, 10:02 AM
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i6pwr
The WB temp under the coils is 62 deg and directly above is 48 deg, WB temp in the rooms away from the supply is 59.5 deg.

Air temp outside of the condenser coil is 76.2 deg and discharge temp is 88, this is ambient temp not WB.

Not sure of the CFM but that meter is next on the B-day list.

The small line temp on the small outside line before the dryer/filter is about 2 tenths warmer nearest the compressor compared to after the dryer.
Well, that is a whole new ballgame.
That gets 29,721-Btuh; well above 2-Ton.

It would have to be pulling hot moist air from the attic or garage to ever get to that high a Btuh number.

There is a 3.5-F WB difference between room air & air right before going into the coil.

using the room WB of 59.5F I get 21,465.6-Btuh; a big difference!
 
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Old 07-29-12, 12:14 PM
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48% RH is fine. Your in a green grass state so if you have a basement a dehumidifier would be wise.
 
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Old 07-30-12, 06:43 PM
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Providing I can keep it at 48% then I guess I can live with it, just seems that another 10% could be had but i'm only speculating.

I have an airflow meter hopefully coming home with me tomorrow and I will get some CFM figures then.
 
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Old 07-30-12, 07:05 PM
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Repeating some:
Well, that is a whole new ballgame.
That gets 29,721-Btuh; well above 2-Ton.

Using the room WB of 59.5F I get 21,465.6-Btuh; a big difference!

It would have to be pulling hot high grains of moisture air from the attic or garage to ever get to that high a Btuh number with a 2-Ton unit.

There was a 3.5-F WB difference between room Return air at the grille & the air right before the coil.

Take both the WB & DB of those two temps, right before the coil & at the Return Air Grilles to see how much heat gain there is.

Hopefully we'll be able to get a ballpark accurate CFM.
Let me know ahead of time what instrument you got & how you're going to take the CFM readings
 
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Old 07-31-12, 09:06 PM
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Wasn't able to pick it up tonight, definately Wednesday. Won't be the most accurate but should give me a very close CFM number based on velocity and duct size. Meter is a Speedtech SM-28 SKYMASTER and also has barometric measurement.

When I test the velocity, I will get the dimensions of the ducting. Does it matter if the reading is above or below the coils?

I wanted to add that when I place the filters in the return, it really draws them in when the unit is running. I know this should be normal to some degree but seems there is an awful lot of suction. When the filters are partially dirty they are caving into the ducting.

Is it normal for a 15x20 airhandler dimension just under the coils, to have an 8x20 return feeding it 2-3' from the coils?
 
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Old 08-01-12, 01:06 AM
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Estimating operating capacity using indoor wetbulb temps is tricky unless you know how much air the system is actually moving.

The following method is better:

1. Find the hp26 spec sheet online to see how much air the condenser is supposed to move
2. Measure the temperature difference between the air going into and leaving the outdoor unit
3. Calculate capacity

Capacity = (cfm x temp difference x 1.08) - (power watts x 3.4 btus / watt)

Your unit is 13 seer, most likely 11 eer...

SEER is efficiency at a lower outdoor temp with an adjustment factor applied; eer is efficiency at 95F outdoor, 80F 50% humid indoor

Therefore...

Power should be between 1846 watts and 2181 watts (80s - 95f outdoor temp) if the system is working correctly

You can measure amp draw with a clamp on meter if you're comfortable doing so.

If the capacity is within 10% of 24000 btus yet the split is too low, you're moving too much air.

If the capacity is low, the refrigerant charge needs to be checked -> pressures, wetbulb temp, line temps
 

Last edited by user 10; 08-01-12 at 01:24 AM.
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Old 08-01-12, 01:14 AM
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Generally air handlers with 1/3 hp motors are designed to move 1000-1200 cfm if the ductwork is decent.

A 2 ton a/c needs 800 cfm, so the fan speed shouldn't be on high unless the duct system is particularly bad.
 
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Old 08-01-12, 01:21 AM
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output = 11.7 x 1860 cfm x 1.08 - (1846 watts x 3.4)
= 17 200 btus give or take a couple thousand

That's pretty bad

Specs: http://www.hvacpartsshop.com/HP26%20Series.pdf

You could have a combination of insufficient indoor airflow and improper charge.
 

Last edited by user 10; 08-01-12 at 01:36 AM.
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Old 08-01-12, 06:44 AM
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Checking airflow CFM

Wasn't able to pick it up tonight, definitely Wednesday. Won't be the most accurate but should give me a very close CFM number based on velocity and duct size. Meter is a Speedtech SM-28 SKYMASTER and also has barometric measurement.

When I test the velocity, I will get the dimensions of the ducting. Does it matter if the reading is above or below the coils?

I wanted to add that when I place the filters in the return, it really draws them in when the unit is running. I know this should be normal to some degree but seems there is an awful lot of suction. When the filters are partially dirty they are caving into the ducting.

Is it normal for a 15x20 airhandler dimension just under the coils, to have an 8x20 return feeding it 2-3' from the coils?
The diffusers will usually change the sf free-air-area or (Ak) as Hart& Cooley calls it.You'll need to measure the grilled area of the diffusers & we'll figure a percent of the sq.in. (to sf) area.

Measure the average FPM Vel., from each diffuser; I believe you can set that meter so it will register FPM velocity readings.

Seems like there needs to be more filter area so the velocity is reduced through the filtering area. I get around 417-fpm velocity through the filter which is above the desirable 300-FPM manual D calls for with a cheap fiberglass filter. What type filters are you using?

Muggle, I appreciate your math work. However, I like the enthalpy chart method for its simplicity. I agree, it's not easy to get a good ballpark CFM reading...
 

Last edited by HVAC RETIRED; 08-01-12 at 06:48 AM. Reason: Clarity...
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Old 08-01-12, 01:08 PM
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One thing I forgot to mention is that it's possible to determine airflow very accurately if the system has electric strip heat.

*The blower tap normally used for cooling must be connected to the heating terminal to do this test

Airflow = (heating watts x 3.4)/ temp rise x 1.08



---------------------------------------
It's better to measure airflow at the air handler since all systems leak to an extent.
 
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Old 08-01-12, 07:56 PM
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Muggle:

The system does have strip heaters. I tried to get a FPM reading just above the heaters and the values were all over the place due to all the hardware in-line with the air flow.

So I removed the filter panel just under the coils and I realize the airflow should rise slightly with the panel removed, I blocked as much of the opening as best I could.

Seems the average reading was roughly 1200-1300 FPM in the center of the ducting. Granted this is just above the 15x20 opening then there is a gradual taper just under the coils I suppose to direct the air into the coils.

I opened the 12x12 return and placed the meter in a good distance and I recorded around the same values.

I do have a clamp meter so if there is another way to verify these readings let me know how to go about this.

HVAC, I did measure the airflow going into the return filters and i'm getting roughly 290-320 FPM at each of the 2 return filters and they are just partially dirty. The higher readings were near the corners and obviuosly in the areas possibly less populated with dust.

Filters are Flanders Precision Aire.
 
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Old 08-01-12, 08:08 PM
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One thing I could do is shut the fan off, place the meter against the coils and close the panels up, then record the MAX in 2-3 locations on each coil.

Not sure if this looks out of place but here's the return entering the AH and the trunk line just inside the top of the AH through the humidifier opening.
 
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Old 08-01-12, 09:17 PM
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I do have a clamp meter so if there is another way to verify these readings let me know how to go about this.

Read more: http://www.doityourself.com/forum/ai...#ixzz22MIcSV4q
1. Change the blower speed so that the speed normally energized in cooling mode is energized on heating mode (switch the wires on the board or otherwise)

2. Turn on the emergency heat (or regular heat + shut breaker to outdoor unit) for 20 minutes - many strip heat kits have sequencers which don't bring all the elements on at once

3. Measure the temperature difference between supply and return. The thermometer shouldn't be in direct line with the heat strips on the supply side

4. Measure amp draw of heat strips at your own risk (alternatively, look up the heat kit model number to determine the kw rating)

Airflow cfm = (240 x heat strip amperage x 3.4)/(1.08 x delta-t)
 
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Old 08-02-12, 04:23 AM
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I may be able to get the readings from the heater tonight. I did however place the meter against the coils and measured both sides with the panels sealed back up and the numbers were more respectable.

I had 556 FPM on the left coil and 553 FPM on the right coil, this was in AC mode not just FAN ON mode. Coil dimensions if my measurements are correct are 15" x 15". Coils are mounted vertically also, like a roof top.

When I measure the heat away from the strips, how far away should I measure? Should it be a supply register or maybe 2-3 feet from the strips?

I can get simultaneous readings just under the coils and above, i'm assuming the same distance would be more accurate?
 
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Old 08-02-12, 08:15 AM
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I had 556 FPM on the left coil and 553 FPM on the right coil, this was in AC mode not just FAN ON mode. Coil dimensions if my measurements are correct are 15" x 15". Coils are mounted vertically also, like a roof top.
Well, 15X15 is 225*.69% free-air-area (maybe a bit high%) is 155.25/144= 1.078-sf * 554.5-fpm velocity is 579-CFM; barely enough for a 1.5-Ton A/C which is normally 600 to 675 or with the usual 2-Ton evaporator coil even 700-CFM.

The minimum CFM for a 2-Ton A/C is 700-CFM, normal is 800 top is 900-CFM.

Kind of appears it's low on airflow through the cooling coil...

Airflow through the Evap-Coil for a 2-Ton condenser needs to normally be, IMO, 750 to 850-CFM, depending on indoor humidity conditions.
 
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Old 08-02-12, 11:00 AM
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The system was removing more moisture when I slowed the fan down. Almost 10% more.
 
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Old 08-02-12, 12:42 PM
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When I measure the heat away from the strips, how far away should I measure? Should it be a supply register or maybe 2-3 feet from the strips?

Read more: http://www.doityourself.com/forum/ai...#ixzz22Q3y0mYd
-----------------------
The thermometer shouldn't be able to "see" the strips. (not in direct line of sight)

The distance otherwise doesn't matter.

Right off the batt, I can tell you that your system isn't providing anywhere near 2 tons of cooling based on the split off the condenser and temp drop across the coil.
 
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Old 08-04-12, 10:07 AM
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I set everything up to measure amps from the strips and my Fluke i410 clamp used inconjunction with my DMM didn't want to cooperate.

Regardless of which wire I clamped I could only get .2-.4mV, not a true reading. Everything was set properly... DC mV and the 9V battery for the clamp was fresh. I clamped every wire basically into the strips and even the hots to the sequencers.....nothing. Something is wrong with the clamp I presume.

I could measure the wires individually if they are less than 20A and feed the meter directly.
 
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Old 08-04-12, 10:45 AM
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When I reconnected the wire tap, I moved the cooling to the MED speed.

I went out and took measurements again and I noticed the temps vary at the top of the outside unit, max was 104 deg and lowest was 99 and the low readings were taken near the front and the higher was towards the rear.

What is the correct position for the temp probe? How far above the fan?

I measured about 1' above the fan and sometimes closer, bulk of the readings were 103-104. The temp entering the coils was 89.8-90...slightly better numbers.

Air temps measured about 6' before the coils and at the closest register from the coils..about 10' downstream...this was after 5 min of running.

Inlet air 73.2 F, 62.2 WB

Outlet air 60.4 F, 55.1 WB Basement register

Temp split outside 14 deg


20 min later:

Inlet air 71.2 F, 62.4 WB

Outlet air 59.3 F, 54.7 WB Basement register

Outlet air 61.3F, 55.1 WB Upstairs register

Temp split outside 15-16 deg.... 89-90 in and 105-106 out

Windows being open for awhile and EM Heat on warmed the house a little, how much does this play a factor?
 
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Old 08-04-12, 12:24 PM
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20 min later:

Inlet air 71.2 F, 62.4 WB

Outlet air 59.3 F, 54.7 WB Basement register

Outlet air 61.3F, 55.1 WB Upstairs register

Temp split outside 15-16 deg.... 89-90 in and 105-106 out
Well, I get a 5.1 enthalpy difference basement.
At 900-CFM that's 20,655-Btuh;
at 800-CFM that's 18,360-Btuh;
at 700-CFM that's 16,065-Btuh.

At those conditions a 13-SEER, 2-Ton Goodman with indoor airflow at 900-CFM, gets 20,600-Btuh: 70 indoors; 63-F WB; 105-F outdoors.

At 900-CFM airflow yours got 20,655-Btuh, that would appear to be on target. Wish we could get a better airflow CFM reading; I hope it is around 900-CFM...if airflow is a lot less, then it's under-performing

Upstairs: 4.92 enthalpy difference;
At 900-CFM 19,926-Btuh; 800-CFM 17,712-Btuh; 700-CFM 15,498-Btuh. Not as good.

The basement must be closer to the coil with less duct run; right? Therefore, a higher delivered Btuh output.
 
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Old 08-04-12, 01:16 PM
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What is the correct position for the temp probe? How far above the fan?

I measured about 1' above the fan and sometimes closer, bulk of the readings were 103-104. The temp entering the coils was 89.8-90...slightly better numbers.
It shouldn't be directly above the heat strips, as to not pick up radiant heat.

Otherwise, take it as close to the air handler as possible.

How many kw is the heat kit?

Which speed is being used for electric heat?

Here's the blower performance chart for your air handler: http://webmanuals.lennoxeurope.com/O...%20install.pdf

Page 13 - table 8.

Unless the static pressure (total pressure drop of the system - including grills, ducts, coil, diffusers) is in excess of 0.8" or so, it should be on low.
 
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Old 08-04-12, 04:16 PM
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Yes, shorter ducting downstairs.

The 105 deg outside was the high end of the outdor coil temp split, 105 from the top of the unit, 90 deg ambient temp.
 
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Old 08-04-12, 05:05 PM
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Before, you said the split outside was 11.7F? Has it increased?

A 15F difference across the condenser coil is okay (a little low, but still okay), given that your outdoor unit moves around 1860 cfm. (source of spec: lennox hp26 manual I think I posted a link to)

qBTUs = (15 x 1860 x 1.08) - 1800-2200 watts x 3.4
= 21 780 - 20 420 being removed



I think your blower is just moving too much air.
 
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Old 08-04-12, 11:29 PM
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Yeah, I was surprised at the increase...could this be the fact it was warmer inside? Only thing I did different was increase the blower speed from low to medium just to try it out....was on high before.

Now that the inside has evened out, I will test the outside split again during the day.
 
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Old 08-05-12, 02:15 AM
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The greater the load on the coil (wetbulb/enthalpy determine that, along with airflow), the greater the cooling capacity.

Based on what you've posted it's still not possible to know if the system is working properly - got to find out how much air the system is moving.
 
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Old 08-11-12, 02:56 PM
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Had some time today to re-test the airflow via the heat strip method. Chalk a duh moment up for me, last test I had the DMM on DC mV instead of AC...No Beer 4U.... Force of habit since I use the DC setting on that clamp alot.

I let the EM Heat run for 20-25 min, I measured the temp from about 10' from the strips on 2 outlets. The 971 won't register tenths above 100 deg but it switched back and forth from 100-101 so I assume it was right at or just before 101 deg, did however spend the most time at 101 though. The WB temp at same locations was 73.6 deg.

Inlet temp 8' from the strips was 76 deg and the WB temp was 62.6 deg.

Fan was on low and outside unit de-energized.

VAC at the strips was measured from another Fluke meter but didn't have hundredths, was a steady 120.0

Amps on each strip was 18.7 after 20 min.

Prior to all this, I used 2 airflow meters and placed them against the evaporator coils in 3 locations...bottom, middle and top. 15x15 coils

Bottom 460 FPM
Middle 540 FPM
Top 630 FPM


Just something to compare to but seems like the strips are the most accurate.

Edited to add, interior space measures 2400 sq.ft
 
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Old 08-11-12, 07:13 PM
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Well, it's strange but I was looking at those Btuh numbers in my last post as tough it were a 1.5-Ton system.

A 6.67 Enthalpy difference will get U close to what that 2-Ton system should be delivering:
At 700-CFM * 4.5 is 3150 * 6.67-enthalpy difference is 21,010 Btuh; 800 * 4.5 is 3600 * 6.67 is 24,012-Btuh; 900 * 4.5 is 4050 * 6.67 is 27,013-Btuh.

Upstairs: only 4.92 enthalpy difference;
At 900-CFM 19,926-Btuh; 800-CFM 17,712-Btuh; 700-CFM 15,498-Btuh. Not as good. Enthalpy difference is too low!

Can't find my 13-SEER 2-Ton Expanded Cooling Data...
 
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Old 08-11-12, 07:19 PM
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Just to be clear on the current, there are 2 strips, each strip has a red lead on one end and a black on the other, each lead registered 18.7 amps.

I'm not 100% on 240V but would that total 18.7 amps x 4 or 18.7 amps x 2?
 
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Old 08-11-12, 07:27 PM
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You just measure the amp draw of one conductor leg of power going to he 240-volt load; then multiply by the measured voltage to get the watts.

Everything in the outdoor condenser is 230-Volts or, actually what voltage you measure; indoors if it's a gas or oil furnace is usually 120-Volts, or what you measure.

Electric furnaces are usually all 230-Volts.
 
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Old 08-11-12, 08:34 PM
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That's what has me slightly unsure, each 120V leg branches to about 4 seperate hot leads, 2 of which go to one side of each strip.
 
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Old 08-12-12, 07:06 AM
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Both legs going to a 230-volt load carry 115-Volts of opposite phase so that the load receives 230-Volts of power/Watts.

You multiply the amps times the volts which is 230-Volts. The amp draw will be half that of a 115-Volt circuit load to obtain the same wattage power draw. Say; 6 amps * 230 volts is 1380-watts

A 115-Volt load has only one leg of power going to it, the other leg is the common or neutral. 6 amps * 115 volts is 690 watts.
 
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Old 08-12-12, 10:22 AM
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I'm still missing something though.

I understand the 230V delivery, actually 240 in this house...both meters read 120V...just mentioning that to be precise on the CFM.

This is what I have:

There is a 60A double breaker in the main panel, feeding a disconnect outside the air handler. This is the only device this breaker in the main panel feeds.






The leads from the main panel are black, then after the disconnect there is one black and one white, I also understand white is typically the neutral. After the disconnect, the UF-B goes straight to the air handler to this 60A breaker.








What has me confused is, this is a double-pole breaker correct? Would the white lead also be a hot? The black and the white both register 120V to ground.

Here's the fan and the fabric on each side of the fan is moist and growing mold.



Whatever the case, I definately need to get the moisture under control ASAP.
 
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