Thread: White Powder From Vents Maytag Furnace

I have a Maytag 95% condensing furnace model PGFITE120CVC that is 1year old and has
about 100 hours on it. It was installed in basement with new metal ducts (exterior fiberglass insulation), metal lined return air and lined output plenum - horizontal furnace.
When starting up this year it is producing fine white dust out of the vents layering
on the floors and furniture.and the A/C installer ( well qualified ) is baffled. There is layering of the fine white powder in the output plenum. The PVC flue is to a masonry chimney
ceramic lined used only for it and the hot water heater. I am thinking the heat
exchanger is defective. Every vent is producing this white powder.
Aluminum or zinc oxide ????
I really need some expert knowledge on this one. I have asked for CO check
but it has not been done.

Thanks Al

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Originally Posted by Al Hendry

I have a Maytag 95% condensing furnace model PGFITE120CVC that is 1year old and has
about 100 hours on it. It was installed in basement with new metal ducts (exterior fiberglass insulation), metal lined return air and lined output plenum - horizontal furnace.
When starting up this year it is producing fine white dust out of the vents layering
on the floors and furniture.and the A/C installer ( well qualified ) is baffled. There is layering of the fine white powder in the output plenum. The PVC flue is to a masonry chimney
ceramic lined used only for it and the hot water heater. I am thinking the heat
exchanger is defective. Every vent is producing this white powder.
Aluminum or zinc oxide ????
I really need some expert knowledge on this one. I have asked for CO check
but it has not been done.

Thanks Al

I would take a sample of the powder to a local analytical laboratory and have it tested to see what I'm dealing with. Next I would most likely open up a duct to see what the inside looks like.

Everything outside of the above would be SWAG.

Thanks for your reply. I will have it tested. We have looked at the ducts
and they look OK. The return air side is clean. There is some
white powder coming out of the holes for the high and low
pipes for the A/C evaporator which would seem to indicate that
the furnace is the problem.. No white dust on A/C useage.
or fan only.

First approach is to check the HE (still sealed), combustion analysis, condensate drain, etc causing corrosion. Seems strange to have vented PVC in abandonded tile chimney chase from the basement and not out a side wall, plus sharing with a WH vent, what efficiency WH/vent type is sharing the chase?

Any signs of leaking down the outside of the PVC? The Pan? - how is the pvc entering the chimney structure?

Although....

How does the air handler filter look? The fan? Any signs of this white dust? Any plaster or gyp sheet work done in the house recently?

Do you have a humidifier, and if so where - return or supply - pad, mist type, etc.? (thinking it could be blown scale and might not have been shut down and cleaned since the last heating season).

Originally Posted by Al Hendry

I have a Maytag 95% condensing furnace model PGFITE120CVC that is 1year old and has
about 100 hours on it. It was installed in basement with new metal ducts (exterior fiberglass insulation), metal lined return air and lined output plenum - horizontal furnace.
When starting up this year it is producing fine white dust out of the vents layering
on the floors and furniture.and the A/C installer ( well qualified ) is baffled. There is layering of the fine white powder in the output plenum. The PVC flue is to a masonry chimney
ceramic lined used only for it and the hot water heater. I am thinking the heat
exchanger is defective. Every vent is producing this white powder.
Aluminum or zinc oxide ????
I really need some expert knowledge on this one. I have asked for CO check
but it has not been done.


Thanks Al

I just re-read the quoted post.

If I'm reading this correctly you are using the tile lined chimney to vent the exhaust of both the high efficency furnace and WH to outside air, PVC is connecting from the furnace to the chimney, and that the PVC does not continue to the outdoors, but transitions to the tile lined chimney which vents to the outdoors...is that the condition/situation?

Is this also your post (where you indicated these deposits were all over the AC coil before you cleaned it) Maytag High Efficiency Furnace problem

Originally Posted by Al on December 3, 2009, 3:44 pm

I have a Maytag High Efficiency [COLOR=blue! important][COLOR=blue! important]Furnace[/color][/color] model PGFITE120CVC (condensing)
It is one year old and is 95% efficency. Worked fine last year
but after starting up this Fall it is producing a fine white
material that is blowing out of the vents. You can only notice as
it is layering out on tables etc. My A/C installer came to see it
and looked at the plenum after the A/C coil and you can see a fine
white powder(looks like dandruff ). [COLOR=blue! important][COLOR=blue! important]Vacuumed[/color][/color] it out and it is still
coming out.
Does not do this on A/C are fan only so it seems that it has
to be related to the furnace. The intake plenum is clean Any ideas my
A/C installer who is very is baffled so far. he is coming back
next week. I asked for a CO check but I think he did not do it.
I am worried that the burner could have a break

Originally Posted by Al on December 4, 2009, 3:48 pm

In addtion it is a basement installation - horizontal with new [COLOR=blue! important][COLOR=blue! important]metal[/color][/color] ducts

I don't recognize the supplied model number as a maytag gas furnace. Don't know of a recent model "horizontal" unless you have a gas-pack HP with air handler in the basement - still doesn't make sense.

Call Maytag and get info to identify your product. 1-800-4AC-HEAT or Nordyne who made/makes Maytag Residential and lt. commercial branded HVAC equipment.

There was plaster work before the last heating season but not this one.
The fan chamber is clean.
The chimney is dual chambered one side for water heater
the other for the furnace.
The 15 year old 80 % Lennox in the attic works just fine thank goodness.
The A/C contracter has installed many of these and he states this
is the first to have this problem. Several of the ducts have been vacuumed as well as the return duct with no improvement.
Odd that it worked well the first season. It seems that if it
were some house dust or debris that it would have lessened after
a month it has stayed the same. Since the white powder is
coming out of the holes for the A.C evaporater and the
fan is clean - it would seem to indeed point to the furnace
heat exchanger.I hated to give up that trusty 1965
Carrier 160,000 BTU furnace never gave a problem.
Attached photo shows layering on wood table near vent.

Al Hendry,

There are significant differences between the venting requirements for a lower efficiency (the 60s Carrier ) higher temperature exhaust furnace and that of a Cat. IV DV or Condensing furnace.

The model number prefix for your furnace would be PGF1 (one) not PGFI ("i") followed by TE (if you've read & typed that part correctly)

Failure to properly vent a high efficiency gas fired condensing furnace can and often will result in corrosive conditions upon the HE.

Please contact an Authorized Nordyne/Maytag rep. As I understand the more recent announcements both Nortek & their Warranty Underwriter are under Chapter 11. If your original installer is ka-put then you'll likely be out of pocket for the inproper installation and its negative effects. If it is found to be a proper installation then supposedly the warranty may be backed up by Nordyne although you might be required to pay out of pocket and hope for a warranty reimbursement claim to be in your favor. Since the Nortek/Nordyne financial situation post-dates my retirement I couldn't say for sure.

On another board a fella claiming to be a NORDYNE employee posted this:

I represent NORDYNE, the manufacturer of the Maytag iQ Drive systems. It's true that Equiguard filed Chapter 11 (which affected more companies than just Maytag), but dealers are getting paid now for warranty work. If you contact us, we can work with you to find another Maytag dealer in your area to service your system. Your warranty is ultimately backed by NORDYNE and it is still good. Please call 1-800-422-4328 and press 4 for warranty. We'll take care of you.

The post was about a month old, hopefully it is correct and perhaps that number will help you.

Since you seem to have missed or ignored the question requesting clarification as to the venting - using the tile chimney chase - and not knowing the path/height of the vent path, am unable to help you further, as it seems you may have a significant problem with how the appliance (condensing furnace rated 95.1 AFUE) has been vented (exhausted).

Perhaps Bob Harper or DavidR or another may be able to help you understand the question's importance and consequences of incorrect venting and its negative effects on the furnace, further.

The installer an authorized Frigidaire Maytag etc. dealer
did the install and it was his decision to go to the chimney not directly out the basement wall. The chimney is about 30 feet from the pvc input
to the chimney opening.
You are correct the model number is PGF1TE120CVC
I am a bit confused as to who is or was chapter 11
Nortek Equiguard and how does that affect Maytag - do they
farm out the warranty?
The furnace has a 10 year warranty from Maytag and is 1 year old
The HVAC installer has checked it 3 times and he just says I have never seen anything like this.

Thanks for all of the input

Maytag is a branded name, used under a license, not a manufacturer of HVAC equipment.

"Maytag HVAC" (NORDYNE, Inc.) has NOTHING TO DO WITH Maytag appliance dealers/manufacturer - and neither does the one appliance authorized service or dealer have anything to do with Maytag-HVAC (Nordyne).

Don't know why you're bringing Frigidaire into the discussion, but it too (HVAC Residential & light commercial) is a branded name manufacturered by NORDYNE).

The Maytag branded HVAC equipment is made by NORDYNE, Inc. which IIRC correctly just filed Ch. 11 in October '09 (held by NTK Holdings also in reorganization - ch. 11 bkrpcy, owned by Nortek, Inc. which is also in Ch. 11 Bkrpcy) under a license to use the trademarked brand name "Maytag". NORDYNE is the manufacturer. The Maytag name for smaller appliances was purchased by whirlpool. Neither Maytag nor Whirlpool (IIRC Whirlpool window/portable Airconditioners were made by Fedders, also in bkrpcy) make/made HVAC and neither is responsible for it. NORDYNE (owned by Nortek) IS regarding manufacture. According to a news report on 12/18/09 Nortek, Inc. emerged from Bankruptcy on that date. THL Partners was somewhere in the ownership chain. I do NOT know if Nordyne, Inc. has also emerged from bankrupcy.

Equiguard (also under Chap. 11 Bkrpcy, as far as I know is still in Ch. 11) is/was the warranty underwriter/administrator for NORDYNE, Inc. manufacturered HVAC equipment branded with the MAYTAG name.

Get a different HVAC person. Call NORDYNE for an AUTHORIZED rep. Gather the Model and serial numbers for the furnace, the AC coil, the AC condenser, the HRV if applicable, etc. and your original invoice and contract from the installation, and call NORDYNE (Maytag branded HVAC)them. Check credentials not only of the company but of the individual HVAC tech. Get a list of OTHER authorized WARRANTY/SERVICE providers for your equipment. Be prepared to send NORDYNE digital photos and copies of your Invoices/contract.

You should have installation and user manuals left by the original install.

If NORDYNE blames the inproper install they will not help you and your 10 or 12 year HE warranty will be useless. If your AC guy didn't install properly do you think he's going to admit it even if he knows he did it wrong (to help you win a suit against him)?

NORDYNE Residential

Cat IV vents are not allowed in masonary chimneys,,where is intake air from?,,combustion air is very important,,Return air could be pulling flue gasses back thru a cleanout in masonary chimney,,

"white Powder" is also a by product of galvanic corrosion seen usually when an acid is introduced to galvanized material

Originally Posted by David Bell

"white Powder" is also a by product of galvanic corrosion seen usually when an acid is introduced to galvanized material

galvanic corrosion has nothing to do with acid it has to do with contact between dissimilar metals on the galvanic scale and the creation of a DC circuit/electron exchange between the metals (cathodic vs. anodic).

Galvanized is zinc treated to inhibit the oxidation of the metal.

Where do you get your information from and how do you form your conclusions from Mr. Bell?

you have never applied acid to galvanized material before? I have to fabricate watertight galvanized products,,I/E pans ,,tubs,, There are many ways that the zink can be corroded

And by the way,,I form my conclusions as everyone does,,from experience,,and listening to others,,although the latter has been less fulfilling lately

Originally Posted by David Bell

"white Powder" is also a by product of galvanic corrosion seen usually when an acid is introduced to galvanized material

I suggest you avail yourself of a search engine and find out just what galvanic corrosion IS.

Because you're mixing applies and bacon and its obvious you don't know what you are talking about.

Originally Posted by David Bell

you have never applied acid to galvanized material before? I have to fabricate watertight galvanized products,,I/E pans ,,tubs,, There are many ways that the zink can be corroded

Sure have - what do you think white vinegar is? What's your point, and what does that have to do with what galvanic corrosion is?

Originally Posted by H.G. Watson, Sr.

I suggest you avail yourself of a search engine and find out just what galvanic corrosion IS.

Because you're mixing applies and bacon and its obvious you don't know what you are talking about.

for the sake of argument I will assume you mean apples,, Have you never seen galvinized smoke pipe with a corrosive powder on it?,,that was not caused by disimilar metals,,it was caused be acidic reaction to flue gasses and moisture

Originally Posted by David Bell

for the sake of argument I will assume you mean apples,, Have you never seen galvinized smoke pipe with a corrosive powder on it?,,that was not caused by disimilar metals,,it was caused be acidic reaction to flue gasses and moisture

Yes apples and bacon (not apples and oranges).

YOU HAVE NO CLUE AS TO WHAT GALVANIC CORROSION IS and more importantly, WHAT GALVANIC CORROSION IS NOT.

General corrosion is NOT Galvanic Corrosion. You were already given "clues" as to what Galvanic Corrosion is (dissimilar metals, anodic/cathodic, current, etc.) and been pointed in a direction for you to acquire the information should you care to.

Mr. Bell you are either innocently or intentionally ignorant. Only YOU can choose to change that condition.

Originally Posted by H.G. Watson, Sr.

I suggest you avail yourself of a search engine and find out just what galvanic corrosion IS.

Because you're mixing applies and bacon and its obvious you don't know what you are talking about.

Originally Posted by H.G. Watson, Sr.

Yes apples and bacon (not apples and oranges).

YOU HAVE NO CLUE AS TO WHAT GALVANIC CORROSION IS and more importantly, WHAT GALVANIC CORROSION IS NOT.

General corrosion is NOT Galvanic Corrosion. You were already given "clues" as to what Galvanic Corrosion is (dissimilar metals, anodic/cathodic, current, etc.) and been pointed in a direction for you to acquire the information should you care to.

Mr. Bell you are either innocently or intentionally ignorant. Only YOU can choose to change that condition.

I find it somewhat funny that you are so quick to assume a persons ignorance. I'm sure being a legend in you're own mind has it's drawbacks,,but please feel free to medicate

Originally Posted by David Bell

I find it somewhat funny that you are so quick to assume a persons ignorance. I'm sure being a legend in you're own mind has it's drawbacks,,but please feel free to medicate

David,

If you are going to get into a pi$$ing match with HGWS make sure you don't misspell any words.

you're is short for 'you are'. The word you wanted to use is your.

it's is short for 'it is'. The word you wanted to use is its.

Humidity – Can affect the electrolytic resistance and transport ions.
Temperature – Temperature can affect the rate resistance of metals to other chemicals. For example, higher temperatures tend to make steels less resistant to chlorides. ,,, Hmm chlorides,,,moisture,, all from a galvanic corrosion site

My inability to spell sometimes does not change the fact that you are not qualified to get in a pi$$ing match without the appropriate weapon

David Bell,

Your posts bring to mind a conversation at the Kiddie table last evening involving my six year old greatgranddaughter, her four year old brother, and my 13 year old granddaughter.

The four-year-old asked for some more "spa-ged-die" (he is having trouble with his "t"s, and had been practicing its pronounciation as he aided his great grandmother in its preparation earlier in the kitchen while perched on a stool).

His six-year-old sister immediately jumped on him verbally (calling him "stoo-pid") and insisted it was properly called "BAH-SKET-TEE".

Causing the four-year-old to burst into tears.

When my granddaughter came around the to console the four-year-old and serve him, she explained to both of them that it was pronounced "SPA-GET-TEE": to which the four-year-old parroted perfectly, smiled and thanked her for the "Spa-get-tee; and the six-year-old called the 13-year old a "stoo-pid" "poopie-head" and that everybody knows its called BAH-SKET-TEE 'cause she'd always called it BAH-Sket-tee!

There is a point there somewhere, does it ring a "bell"?

Kinda reminds me of a guy that calls someone ignorant ,,then doesn't admit that the persons post confirms the original thought

Originally Posted by David Bell

Kinda reminds me of a guy that calls someone ignorant ,,then doesn't admit that the persons post confirms the original thought

No David Bell. YOU and my six-year-old great granddaughter have something in common. The difference is, she has learned many things since I last posted and is now having pleasant dreams and will process what she has learned throughout the day. We cannot say the same for you.

We still do not have a direct answer to the issue about PVC venting into a masonry chimney. Al, can you clarify if this PVC terminates into a masonry chimney flue or if it uses the masonry flue as a *chase* but is fully lined up to the top of the chimney and properly terminated with PVC or not?

If the PVC is just stubbed into a masonry chimney, it is a carbon monoxide hazard since masonry chimneys are designed and approved for negative vent pressure only. Another issue is massive condensation. Masonry chimneys suffer from condensation even with 80% furnaces---a 90+ would be a death sentence for sure to any masonry chimney. I would expect to see condensation issues in the walls and ceilings next to the chimney. The third issue is proper venting. A CAT IV furnace relies on mechanical exhausting to the atmosphere. However, a cold masonry chimney is full of cold dense air. Atmospherically vented appliances have a tough time warming these flues and getting them 'primed' so they draw rather than backdrafting. Until you push that slug of cold dense air up out the chimney, it will create a lot of backpressure. It may not prove to be enough to trip out the pressure switch or high limit switch on the furnace. A scary thought would be that the positive pressure is finding a bypass into the home. Even if the furnace does not trip out, the retarded venting cannot be good for the furnace and puts it outside the design limits.

The improper venting voids the warranty and listing and is a code violation if indeed this is how it is vented. Even correcting the venting would probably void the warranty since damage has probably been done.

Without a lab test, all you can do is speculate what the white particulate matter is. It would be interesting to open the furnace and see if this same matter is in both the venting and the warm air system and closely inspect the HXs for defects. Then, fire the unit, & perform combustion analysis.

Perhaps we can get DavidR to comment, if he isn't out chipping ice.
Bob

Al,

It sounds to me like you've got a venting problem. I'm making some assumptions here though. It sounds like your Maytag furnace is installed in the basement. The pvc vent runs 30 feet to the chimney. If this is a direct vent furnace the maximum you can vent with 3" pvc is 40 feet. I'm assuming this is a two story house with an attic as you have another furnace in the attic. Therefore I can safely assume that the distance from the basement to the top of the chimney is over 10 feet. Chimneys should only be used as a vent chase if they are sealed at the top and insulated.

Now if your furnace is set up as an indirect vent (no pvc supply air duct) then your maximum length of the vent moves up to 57 feet if you have two 90 degree elbows and goes down with the addition of more elbows. Using 30 feet across your basement leaves you a maximum of 27 feet. The top of your chimney is probably higher than that.

Galvanic corrosion can also form on a single type of metal when an electrolyte is heavily concentrated in one area of the metal.

What are some factors that can influence the formation of galvanic corrosion?

• Higher temperature and humidity tend to make steels less resistant to the electrolytes that cause galvanic corrosion
• Strong acids= strong electrolytes

That will be my last post on the subject of galvanic corrosion. I hope this clears things up on what is and what is not galvanic corrosion.

As I said in the first post! Everything else will just be a SWAG. Folks are really guessing on what is going on. Have the powder tested and then decide on a course of action.

Re-reading some of your post, I wonder if the evap coil is clogged with plaster or drywall dust and it is now working free. Have you have he A/C coil cleaned?

Again, have the powder tested and then decide.

Originally Posted by David Bell

Galvanic corrosion can also form on a single type of metal when an electrolyte is heavily concentrated in one area of the metal.

No that's just not true.

Galvanic corrosion (dissimilar metal corrosion) is the process by which the materials in contact with each other oxidizes or corrodes. There are three conditions that must exist for galvanic corrosion to occur.

1.) There must be two electrochemically dissimilar metals present,
2.) There must be an electrically conductive path between the two metals (for the metal ions to move from the more anodic metal to the more cathodic metal), and
3.) The metals must be exposed to an electrolyte.

If any one of these three conditions does not exist, galvanic corrosion will not occur.

Definitions:

Galvanic Corrosion - Electrochemical corrosion associated with galvanic cell current resulting from the potential (emf) between dissimilar metals in an electrolyte. Dissimilar Metal Corrosion.

Galvanic Cell - A cell created by electrically connecting dissimilar metals or alloys in contact with the same body of an electrolytic solution such as seawater. A current then flows, accelerating the corrosion of the more active metal and preventing the corrosion of the less active metal until the more active metal is consumed.

Galvanic Protection - (1) The protection of a metal from deterioration by the selective use of galvanic corrosion in which the metal is connected to another, more active, sacrifical metal. Both metals must be in contact with the same body of an electrolytic solution such as seawater. Zinc, magnesium, or aluminum can be used as sacrifical metals for the galvanic protection of steel. (2) Protection of a metal in contact with an electrolytic solution from corrosion by the use of an impressed direct electrical current,

Sacrificial Protection - The protection of metal from corrosion by using a coating or metal anodes. In the case of the former, a metallic coating is used, such as galvanizing or zinc-rich paint, to protect steel. In the presence of an electrolyte, such as salt water, a galvanic cell is set up and the sacrifical metallic coating corrodes instead of the steel. In the case of the latter, sacrificial metal anodes are used to protect immersed metals such as ship bottoms.

Galvanized Steel - Steel that is coated with a zinc layer to protect it from corrosion. Galvanized steel is remarkably corrosion-resistant, because even if a scratch appears on its surface, the zinc coating will nevertheless protect the steel beneath.

Electrochemical Corrosion - The corrosion of an alloy or metal caused by the flow of current in an electrolyte.

Concentration Cell - A voltaic cell in which a difference in concentration causes the electromotive force. The difference in concentration may refer to a difference in electrode concentration (metal or gas) or to a difference in electrolyte concentration.

Concentration Cell Corrosion - Electrochemical corrosion which takes place in a concentration cell.

Voltaic Cell - A cell in which chemical reactions occur at the surfaces of the two electrodes, which dip into an electrolyte thereby producing a voltage. Voltaic cells can be thought of as a combination of two half-cells.

Potential Difference - The potential difference between two points is quantitatively equal to the difference in the values of electric potential at the two points. Equivalently, potential difference equals the amount of work necessary to move a point charge from one point to the other. A potential difference may also refer to the voltage difference between two points in an electric circuit.

Anode - The electrode to which electrons move in a completed circuit.

Cathode - A negatively-charged electrode, such as in a storage battery. The electrons flow from the cathode in a completed circuit.

Sacrificial Anode - An anode consisting of a layer of a metal that is more reactive than another preferred metal electrically connected to it. The sacrificial anode will then corrode in lieu of the desired metal.

Galvanizing - A metal finishing process in which zinc is deposited on a metal's surface by means of hot dipping, sherardizing, or electroplating.

Again thanks for all of the information.
To answer a few questions
The chimney is double chambered ceramic lined on the furnace side
The PVC line from furnace to the chimney is about 4 feet
The installer sent the line to the chimney at the bottom only
Thanks to the advice here I have notified the installer of the error
He is in New York but will come by next Tuesday and inspect the
evaporator coil
He said that he will run the PVC to the outside wall a run of about 20-25 feet
Bad news about Nordyne and their "Brands" and the insurer
If worse comes to worse I will have to eat this furnace and
get a Lennox or Trane furnace ( they would seem to be stable
but who knows these days )
Frankly I would refer a basic 80% after this experience and I live in
a warm climate Louisiana ( no Chinese dry wall in this 1920 house )
To be fair the furnace does heat very well . Went to the top of the
chimney (about 35 feet up from the PVC input ) and the warm air is
emerging but worried about the corrosive fumes. With less than 100 hours
on the furnace I think it is too soon for significant damage to the chimney.
Will keep you informed on the outcome.
And yes if necessary will get the white powder tested
Al

Originally Posted by Al Hendry

Again thanks for all of the information.
To answer a few questions
The chimney is double chambered ceramic lined on the furnace side
The PVC line from furnace to the chimney is about 4 feet
The installer sent the line to the chimney at the bottom only
Thanks to the advice here I have notified the installer of the error
He is in New York but will come by next Tuesday and inspect the
evaporator coil
He said that he will run the PVC to the outside wall a run of about 20-25 feet
Bad news about Nordyne and their "Brands" and the insurer
If worse comes to worse I will have to eat this furnace and
get a Lennox or Trane furnace ( they would seem to be stable
but who knows these days )
Frankly I would refer a basic 80% after this experience and I live in
a warm climate Louisiana ( no Chinese dry wall in this 1920 house )
To be fair the furnace does heat very well . Went to the top of the
chimney (about 35 feet up from the PVC input ) and the warm air is
emerging but worried about the corrosive fumes. With less than 100 hours
on the furnace I think it is too soon for significant damage to the chimney.
Will keep you informed on the outcome.
And yes if necessary will get the white powder tested
Al

The installer should be liable/responsible. It would be very unsafe (possibly deadly) to continue to operate this furnace as you describe its installation.

Personally I wouldn't trust this installer to correct. I recommend you get at least one (preferably two) independant party in to examine, inspect and memorialize the improper installation. I would also recommend you contact NORDYNE and go through the procedures for their review which would 1) memorialize the situation and confirm improper installation and its effets upon the equipment, and 2) put NORDYNE on notice that one of their "distributors/servicers" is doing such work. Such negligence is actionable and without excuse.

The integrity of the Heat exchanger/sealed combustion chamber may be irreversibly compromized, i.e. corrosion fatigue. Gosh only knows if this installer has jumped safetys or if the boards have been damaged, etc.

Stainless Steel +galvanized metal screws a reported complaint on this line.

FYI:

Corrosion Fatigue - Fatigue in metal due to fluctuating fatigue stresses combined with corrosion. Corrosion fatigue may lead to failure of a metal part.

I just happened across this posting. Not sure if a solution has been found. Let me lend what little experience I have to the situation. With the powder showing on the coil, but the blower being clean it seems the furnace is making the powder. When the condensate from the products of combustion dries it leaves a white powder (I don't care what type of corrosion it is). This furnace will condense, however, under no circumstance, regardless of how the furnace is vented, should any products of combustion (vapor or liquid) contact the conditioned air stream. I suspect that there is some breach in the heat exchanger allowing moisture into the air stream where it dries and leaves behind the powder. Hope this helps.

"Re: White Powder From Vents Maytag Furnace
Quote:

Originally Posted by David Bell
I find it somewhat funny that you are so quick to assume a persons ignorance. I'm sure being a legend in you're own mind has it's drawbacks,,but please feel free to medicate


David,

If you are going to get into a pi$$ing match with HGWS make sure you don't misspell any words.

you're is short for 'you are'. The word you wanted to use is your.

it's is short for 'it is'. The word you wanted to use is its."


Bruce, did it make any difference that the wrong words were used?Did you not understand the make up of the sentence?I'm sure everyone understood what David wrote regardless of a few wrong words.Are you so perfect?

Here is the latest on the Maytag Furnace. The evaporator coil was removed
and the white dust was coming from the furnace. Here is a photo of
the plenum and the furnace heat exchanger. I was told that the furnace heat exchanger
is aluminized steel. Other than knowing that the dust is coming from the furnace no one
knows what it is. Frigidaire is replacing the coil, furnace and plenum. The old units
will be returned to the factory.

Sure looks like sheetrock dust to me. Not a big fan of duct liner either, it's very rarely installed correctly.

The house is all plaster. The ducts are unlined metal , that is just the outlet plenum.
The intake plenum was absolutely free of the white material. The furnace was
run without the evap. coil and dust was pouring out.

Scarfaces' crib?

From what we have been able to draw out of the OP, this furnace was improperly vented from day one. You cannot vent a CAT III or IV gas appliance into a masonry chimney unless it has been relined with a liner listed to UL 1738. PVC does not meet this std. In fact, as we speak we are working on adding a separate portion to the UL 1738 listing for plastic venting. The Canadians have it under B149.1/ S-626

Since this unit has been exhausting into a masonry chimney that required natural draft, there has been back pressure on the furnace exhaust from day 1. This probably has resulted in a shortened lifespan of the appliance as well as the masonry chimney.
I recommend a professional inspection and testing of the appliance by a third party and a Level II inspection of the chimney.
The furnace should have a two pipe vent system per the listed instructions.

Originally Posted by Bob Harper

From what we have been able to draw out of the OP, this furnace was improperly vented from day one. You cannot vent a CAT III or IV gas appliance into a masonry chimney unless it has been relined with a liner listed to UL 1738. PVC does not meet this std. In fact, as we speak we are working on adding a separate portion to the UL 1738 listing for plastic venting. The Canadians have it under B149.1/ S-626

Since this unit has been exhausting into a masonry chimney that required natural draft, there has been back pressure on the furnace exhaust from day 1. This probably has resulted in a shortened lifespan of the appliance as well as the masonry chimney.
I recommend a professional inspection and testing of the appliance by a third party and a Level II inspection of the chimney.
The furnace should have a two pipe vent system per the listed instructions.

Well said.

But an abandoned masonry chimney can be used as a chase for a properly piped direct vent appliance.

Al, you are the only person I have found that ALSO has this problem. If I took pitures of my ducts it would look very similar. Has the replaced unit fixed your problem? I did not for me.
Jeff