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#4136784 - 06/27/16 09:51 PM HVAC Evaporator Cleaning Results
sleddriver Offline


Registered: 02/06/10
Posts: 4599
Loc: Central Texas
Took time to attend to this Sat. evening, as it had been about 2yrs. (I think). I usually do it once/yr. My unit is an upflow, located in the living-space closet, so access is easy.

There was a bit of mold on it, as well as some dirt that had balled up due to being wetted. Completely sealing the return air plenum decades ago means only filtered air now gets to the coil.

I sprayed down both inner sides of the A-frame evaporator coil with TuffStuff, then let it soak for 15 min. TF works great as it foams up inside the coil, thoroughly wetting all inner surfaces. Plus it contains the same ingredients as the other "pro" canned cleaners...at 1/4 the price. I then pulled the residue down to the bottom with a stiff brush.

I then rinsed it down with a couple gallons of softened water as I was clean out of distilled. The squirrel cage looked fine: Just a very thin layer of dust on it.

What's interesting is the difference in indoor humidity removal. Before, it was fine as the house stays at about 44% Rh, despite the high humidities of late.

Post cleaning though, the indoor Rh has dropped even lower to 35%! As I type, these are the conditions:

Outdoor ambient: 84F
Outdoor Dew Point: 75F
Outdoor Rh: 73%
Heat Index: 93F
Indoor temp: 78F
Indoor Rh: 35%
Delta-T across the coil is about 20F

Early evening until mid-morning, the t-stat = 77F. Then it's raised to 82F. I've noticed that the indoor temp will rise about 1/hr or so later on, then level off. Indoors it feels very comfortable and dry, compared to outdoors, even with the higher temp setting during the day.

When I walk in from outdoors, I can really feel the humidity just fly off my skin, hair, clothes, etc. as it immediately begins to evaporate.

This level of performance from a now 26yr old Janitrol unit!

I doubt it would have lasted this long without removing the flow rater and upgrading to a Sporlan TXV back in the mid-90's, as a TXV is just a superior refrigerant metering device. I also had a sight glass installed just before it so I could keep an eye on refrigerant levels.

I also designed & installed a new duct system based on both Man J & D calculations. The unit has become a bit oversized due to the "tightening" of the house + additional insulation + new shingles. The former duct system was woefully inadequate, far too restrictive and created too much turbulence. Plus it couldn't be properly balanced.

The fan is currently set on LOW as it creates to much suction on the return side, bowing in the 20x24 filter. Even a new filter bows a bit on LOW. I cut in an additional 144 sqr. in. of return air to allieviate this, but now think I'll go with a 20 x 30 x 2" return air filter. (The original installers must have run out of 20x25 grille frames and found the x24 somewhere. So I got stuck with it).

Here, latent heat removal is just as important as sensible, due to our high dew points. Humidity removal depends on a cold, clean evap. coil and sufficient airflow through it.
_________________________
1998 Volvo V70 T5 226,808 mi. Original Owner.
M1 10W-30 HM
"It's never a mistake to buy tools, defined broadly. They're not a cost, they're an investment." - J.B. Peterson

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#4136807 - 06/27/16 10:15 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
Reddy45 Offline


Registered: 08/15/08
Posts: 2963
Loc: USA
Impressive stuff. Are you a tradesman?

I redid my ductwork one year and after that project gained a ton of respect for the HVAC industry. I only managed to step/fall through the ceiling 3 times.....I'm pretty [censored] good at patching drywall now.

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#4136952 - 06/28/16 06:33 AM Re: HVAC Evaporator Cleaning Results [Re: Reddy45]
JC1 Offline


Registered: 11/29/08
Posts: 3001
Loc: Oshawa, Ontario Canada
Originally Posted By: Reddy45
Impressive stuff. Are you a tradesman?


+1, sounds like you have that AC unit running like a champ.
_________________________
2015 Grand Caravan SXT Plus 5w-20 PPPP/Wix Filter
1997 Honda Civic CX 5w-30 PPPP/Mahle Filter

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#4137253 - 06/28/16 12:32 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
sleddriver Offline


Registered: 02/06/10
Posts: 4599
Loc: Central Texas
Thanks guys!

Not in the trade. Wanted to maximize its efficiency to remove humidity and keep the bills low and prevent it from dying a short death as the previous system did.

So I bought a used HVAC textbook and began reading, then a gauge set to read the pressures myself. The refrigeration cycle is very interesting and necessary down here.

Stay Cool!
_________________________
1998 Volvo V70 T5 226,808 mi. Original Owner.
M1 10W-30 HM
"It's never a mistake to buy tools, defined broadly. They're not a cost, they're an investment." - J.B. Peterson

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#4138093 - 06/29/16 10:02 AM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
Smokescreen Offline


Registered: 05/25/05
Posts: 3356
Loc: Alberta, Canada
Sounds great. Now you know what to do a yearly maintenance schedule will keep it running like a top for as long as possible.
_________________________
09 Corolla 1.8L-370Kkms(231Kmi)-PP,Denso
05 LeSabre 3.8L-210Kkms(131Kmi)-Sopus,Wix
03 Sierra 2500 6.0L-204Kkms(127Kmi)-Sopus,Wix

All with mpg > EPA

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#4138262 - 06/29/16 01:16 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
HTSS_TR Offline


Registered: 04/17/06
Posts: 19528
Loc: Lake Forest, CA
Originally Posted By: sleddriver
Thanks guys!

Not in the trade. Wanted to maximize its efficiency to remove humidity and keep the bills low and prevent it from dying a short death as the previous system did.

So I bought a used HVAC textbook and began reading, then a gauge set to read the pressures myself. The refrigeration cycle is very interesting and necessary down here.

Stay Cool!

You're sounded like an expert. I read your post more than once and I didn't know what you are talking about.

If I think my HVAC is needed some maintenance I will contact a pro in my area.


Edited by HTSS_TR (06/29/16 01:17 PM)
_________________________
'00 MB E430
'04 Honda S2000
'06 Volvo V70
'14 Honda Accord LX
"Throwing food away is like stealing it from the poor and hungry" Pope Francis

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#4138421 - 06/29/16 05:18 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
LoneRanger Offline


Registered: 07/02/07
Posts: 4055
Loc: Midwest USA
Wish my evap coil was as easy to access.
_________________________

'09 Subaru Forester ...................(QSED DEXOS1 5W30)
'16 Moto Guzzi Stelvio 1200 .....(ENI i-Ride PG 10W60)

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#4138430 - 06/29/16 05:32 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
spasm3 Offline


Registered: 05/30/10
Posts: 8642
Loc: North Carolina
My coil is 20 years old, would there be any risk of causing a leak by using a coil cleaning spray? I see you used tuff stuff. Are the self rinsing coil sprays ok?


Edited by spasm3 (06/29/16 05:34 PM)
_________________________
13 elantra 68k 5w30 QSUD
03 chevy avalanche76k synpwr 10w30
01 saturnsc1 185k synpwr rebuilt
17 mazda cx-5 3900 miles m1 0w20/0w40 mix

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#4139198 - 06/30/16 02:12 PM Re: HVAC Evaporator Cleaning Results [Re: spasm3]
sleddriver Offline


Registered: 02/06/10
Posts: 4599
Loc: Central Texas
Originally Posted By: spasm3
My coil is 20 years old, would there be any risk of causing a leak by using a coil cleaning spray? I see you used tuff stuff. Are the self rinsing coil sprays ok?

Cleaning causing leaks???

TS contains 2-butoxyethanol, surfacants, and sodium metasilicate. Same thing I found in the "pro" stuff in cans.
_________________________
1998 Volvo V70 T5 226,808 mi. Original Owner.
M1 10W-30 HM
"It's never a mistake to buy tools, defined broadly. They're not a cost, they're an investment." - J.B. Peterson

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#4139369 - 06/30/16 05:00 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
SHOZ Offline


Registered: 06/28/03
Posts: 5744
Loc: Illinois
I need to clean mine off and level it. Last summer I opened it up and it looked clean but water stays pooled on the bottom of the coil drain. Only way I can see to change the level is to level the whole furnace. It is a downdraft and goes though the cement garage floor then under the hose in the crawl space.
_________________________
2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual

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#4139621 - 06/30/16 09:36 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
spasm3 Offline


Registered: 05/30/10
Posts: 8642
Loc: North Carolina
Originally Posted By: sleddriver
Originally Posted By: spasm3
My coil is 20 years old, would there be any risk of causing a leak by using a coil cleaning spray? I see you used tuff stuff. Are the self rinsing coil sprays ok?

Cleaning causing leaks???

TS contains 2-butoxyethanol, surfacants, and sodium metasilicate. Same thing I found in the "pro" stuff in cans.


Thanks, I think mine could use cleaning.
_________________________
13 elantra 68k 5w30 QSUD
03 chevy avalanche76k synpwr 10w30
01 saturnsc1 185k synpwr rebuilt
17 mazda cx-5 3900 miles m1 0w20/0w40 mix

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#4139873 - 07/01/16 07:28 AM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
SHOZ Offline


Registered: 06/28/03
Posts: 5744
Loc: Illinois
The stuff I have is made by Nu-Calgon and is called Evap Foam No Rinse. I got it from Amazon. The foam bubbles break down and then the condensate will rinse it off. Unless there is physical debris no water washing is needed.
_________________________
2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual

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#4180751 - 08/18/16 06:09 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
sleddriver Offline


Registered: 02/06/10
Posts: 4599
Loc: Central Texas
Update:

A neighbor recently came over and noted "It's freezing in here. Why do you keep it so cold?" I looked at him in puzzlement for a moment, then pointed to the Davis Vantage Pro weather system display located in the kitchen:

Indoor temp: 79F
Indoor Rh: 33%

I said it's not that it's cold in here. It's just very dry. He'd been outside where around 9pm it was still 91F and probably 60% Rh. All the moisture he carried inside, quickly evaporated thus giving him a chill.

He stared at the display for a few minutes while I replied "I haven't even turned it down for the evening yet. Just got out of the shower, started cooking and it didn't even feel warm." I encouraged him to get his evap. coil cleaned (3 of them) and be sure his return air ducts are all sealed up and only drawing conditioned air from within the building envelope, instead of warm, moist air down an open stud cavity, attic, etc.

Another experience:

Local community library. Running about 8 residential A/C units. Two story building. Main entrance uses a double door, separated by about 25' between them. Thus, minimizing outdoor air coming into the main area & vice-versa.

Immediately noticed the humidity one day. T-stat read 76F, but it was just DAMP and Muggy. The director happened to be in, so I asked how it felt to her. After messing with a t-stat in her office, we displayed the humidity: 60%!! In a library...with lots of paper books!

I said something is seriously wrong for it to be that high, indoors. She said they had yearly services & regular filter changes. I asked when the last time the evap coils (all 8) were cleaned. Response? TILT. I replied it should be no higher than 50% and preferably in the mid-40's...after all, it IS a library. She made a note and said "We'll look into it."

The mold & fungus count is ALWAYS HIGH here in this "humid, sub-tropical climate". Lots of people walking in over time, deliver spores on their clothes, hair, shoes, where they are let loose. Since paper is cellulose, M&F consider it a food source. Add plentiful moisture and indoor environment turns into a Petri-dish.

I wish more people took this seriously. They'll pay the high electric bills and get taken for SEER > 25 systems @ $3000/ton, but not get the duct work checked, nor the coils cleaned.

Geesh....I ought to go into that business!
_________________________
1998 Volvo V70 T5 226,808 mi. Original Owner.
M1 10W-30 HM
"It's never a mistake to buy tools, defined broadly. They're not a cost, they're an investment." - J.B. Peterson

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#4428733 - 06/11/17 04:51 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
sleddriver Offline


Registered: 02/06/10
Posts: 4599
Loc: Central Texas
UPDATE:

Due to a lack of both availability & choices regarding 20" x 24" AC filters, and needing to upsize the return air filter, I chose a 20x30" new return air grille & filter. This results in a 25% increase in surface area, and will prevent the filter from bowing in with the blower set on HIGH (which is necessary to move sufficient CFM across the evap. coil).It will also result in a lower pressure drop and stop occasional 'whistles'.

Increasing the width was easily done by removing two 2x4 criples with the Sawzall and trimming back some drywall.

A plus with the new grille is that the hinged portion is removable for access and outdoor cleaning, unlike the older one.

Next I thoroughly foamed the evap core with TuffStuff and let it work for 15min. Then I brushed the face from top to bottom, sprayed again, waited another 15min., then rinsed with soft water + some bleach to clear the coil & rinse out the drip pan.

My final task is to form some sheet-metal into arcs to reduce turbulence across the rough cut-outs made in the 3/4" plywood decades ago by the original installers. I thought of using HVAC mastic, but wasn't sure it would hang-in-place without falling/slumping while setting up. I also thought about making a quick air guide from 2" dia very-thin-walled clear plastic tubing to straighten the air flow across this rough junction, reducing swirling and turbulence.

Time to clean the condensor coil next and clean out any ants from the electrical box...
_________________________
1998 Volvo V70 T5 226,808 mi. Original Owner.
M1 10W-30 HM
"It's never a mistake to buy tools, defined broadly. They're not a cost, they're an investment." - J.B. Peterson

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#4428787 - 06/11/17 06:05 PM Re: HVAC Evaporator Cleaning Results [Re: sleddriver]
SHOZ Offline


Registered: 06/28/03
Posts: 5744
Loc: Illinois
When I cleaned mine last year I could not get a direct spray on the face of the coils. The access opening is on the front and there was very little room. I though at the time what i need is a spray wand with a 90* end.

Well I found this for the next time. It has both a water wand and air wand with squeeze handles for control. The head is about a 45* angle.

Radiator Genie
_________________________
2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual

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