Drywall dust and Furnaces

[rsisson]

I am a Home inspector working in Maryland.

I have read posts by individual installers saying that they won't warranty furnaces if they are run prior to drywall being done...

Is there any INDUSTRY source of anything stating that drywall dust can/does cause damage...etc...

As it has gotten cold, more builders are starting furnaces before the drywallers are done...

MOST builders protect floor registers, but returns and wall/ceiling registers are left unprotected.

I routinely open the fan compartments and can clearly write my name in the dust covering everything. I provide a picture and tell my clients to ask for a PROFESSIONAL cleaning (not just sweeping out the compartment).

In one recent case, the blower was caked with drywall and saw dust, there was a coke can in the compartment and bits of drywall...Oh yes, there was a new clean filter in place....

What can I give my clients that will arm them to ask for a proper cleaning, a new furnace, or an extended warranty in these cases. The Installing company's are out of the area when the development is done and they won't offer any help as it would be cutting of their nose to spite....

There is only ONE builder in the area who stuffs ALL ducts with fiberglass bats prior to drywalling and pulls the fuses on the furnaces. When the drywallers are done, they p vacuum, pull the plugs and fire up a CLEAN furnace... but they are very unique...

Again, what I am looking for is some backup from a industry source that can help my home buyer clients get a clean furnace with all of its expected life...



[Edited by rsisson on 12-10-2005 at 01:23 PM]

[drk]

Unit should not be turned on tell a week before closing on the home. Contractors should provide temp heat

[t527ed]

not sure about all manufacturers but LENNOX states in their installation manual that heater is NOT to be used as a construction heater.

[MikeJ]

What's worse than that is to have a homeowner looking over your shoulder of a unit that your company put in a year ago and you have to explain......tell the truth and they are on the phone demanding a new unit and you are on the boss's **** list forever. To avoid that, you have to be a politician very fast.


**** (just checking to see if I typed **** if it would spell out the word I really used. Kewl tool boss.)

[Edited by MikeJ on 12-10-2005 at 11:11 AM]

[smokin68]

That dust is in more than the blower compartment......ductwork too.

[amickracing]

We turn ours on around half of the time, and I cringe every time we do. We haven't had any problems yet... that's thier reasoning behind it, but that one problem could really bite us in the tail.

We generally cover return openings with panning or cardboard, supplies with metal covers. When we start them we bend the metal up so there's an opening but not all the way open to prevent dirt from getting swept into it. The returns generally stay covered. But 99% of the time the basement isn't finished, and the panning is left open down there until we finish, so it draws return from down there where there's not as much dust.

I wouldn't have any problem running the furnace for anyone but the drywallers and painters (if they are spraying) since they make the most mess. Tile guys, carpet guys, us, plumbers and electricians, they are all pretty clean.

[rsisson]

The problem that I see a lot is that the installing contractor is NOT the one being called back for Maintenance or Repairs.

The low bid installing contractor does NOT leave a sticker on the unit, so the client is left to the "open Market" when they have problems past the initial "warranty" period.

The new incomming contractor opens the unit, sees the mess left behind and informs the owner that the blower and controller (and more) are a mess and they won't warranty it... OUCH!

That is what I am trying to prevent.

Do any of you have generic wording, or better yet, a link to an industry page that describes the problems drywall dust can cause?

What I have also been seeing, is that the "punch out" guy is told "clean it" and he sweeps the blower compartment... the fan, the controlls, and the (unseen) A-coil and heat exchanger are still covered in dust.

I know YOU guys want to do the right thing, and need to keep the builders happy, but it is my client who ends up with a degraded or shortened life furnace. I am looking for something that works for everyone...

[docholiday]

The only solution is to not run the system and have the ductwork cleaned before you use it. The builder needs to know that the furnace is not to be used for temporary heat. The drywallers, just like any other contractor can provide their own heat. If they're too cheap then the gc can provide it.

You can install the unit, stuff all registers and returns with insualtion (so you can remove it later) and then remove the main board. If the GC insists it be made to run he can sign off on a form that says he understands the unit has no waranty.

[wisc]

The major component of drywall is gypsum (calcium sulphate - sulpher) along with potassium sulphate, boric acid and in some cases lime, all natural enemies of copper windings and aluminum coil fins. All thats needed is some humid air to start the corrosion process. Add to that the reduced heat/cool transfer caused by a layer of dust, plus a possible out of balance blower wheel, other drywall components like silica, mica and paraffin wax (see your MSDS) and some time - your furnace / air conditioning system just won't be what it could have been.

These components mentioned above are just in the drywall. Each joint compound manufacturer has a dozen or so blends with other additional components to add to the mix.

Running a furnace with cold return air temperatures can cause the flue gases to condense inside the heat exchanger, by itself a problem with out any dust.

Even with warmer return temperatures, those furnaces not using outside air for combustion would be drawing construction dust into the burners and through the heat exchanger. In addition to the buildup of dust in the burners causing improper combustion / sooting, we have a potential corrosion process starting inside the heat exchanger caused by elements in the dust.

As far as I know, furnace and fireplace warranties are void if they are used for temporary or construction heat.

[rsisson]

"As far as I know, furnace and fireplace warranties are void if they are used for temporary or construction heat."

This is exactly what I am trying to find the source of....

If I can make a builder buy a few new furnaces it won't be long before he changes his proactices...

Then there is the battle as to what is "construction or temporary heat"

[pecmsg]

Contact the manufacture via E-Mail and ask them directly.
Every warranty I have ever read states something to the effect of “Normal operating condition”

[ryan_the_furnace_guy]

I have actually heard of contractors shrink-wrapping the furnace with a note that says "removal of shrink wrap will void warranty". The drywall dust gathers on the windings of the motors, among other places, and causes them to overheat and the mixture becomes acidic...and well...the rest you can imagine. As for any publications on the subject I don't know of any.

[wisc]

From Lennox G50/51 warranty:
WARRANTY LIMITATIONS

2 − This warranty does not cover damage or defect resulting from:

e − Operation of furnaces or AM30 or AM61 air handler with return air
temperatures of less than 60°F (16°C) or operation of a furnace or
AM30 or AM61 field installed downstream from a cooling coil.

[cem-bsee]

bearings, bearings
my sad experiences with sheetrock dust are with bearings -- especially of a shop vac -- vac lasts 3 months after cleaning a bunch of sheet rock dust --

just having the blower motor windings blocked with dust will cause the windings to be hotter because of the lack of air flow --

getting sheetrock dust into electrical contacts will cause arcing & quick failures.

go after the general contractors -- they get the big $ -- they set the tone | standard | criteria

being an engineer, I would advise HO to not buy the house; if bought would sue because of bad workmanship!

BTW, some of the installation manuals should be by the furnace --

[ryan_the_furnace_guy]

Originally posted by cem-bsee
BTW, some of the installation manuals should be by the furnace --

By code.

[contactor]

You can find in the installation instructions of every furnace I sell { Furnace not to be used for temporary heating of buildings or structures under construction }
I read this out of a frigidaire instruction manual.Have seen it in Rheems,Comfortmaker,Goodman,etc.
Your not only dealing with drywall, but paint and varnish mist,sawdust, debris swept into return air vents,lunch garbage,pop @ beer cans,and paper and plastic bags that often end up in the squirrel cage. The motor,squirrel cage,primary @secondary heat exchanger,burners,ignitors and sensors are all compromised.
The best duct cleaning company will not clean it 100%,nor reverse the damage done,but they will the closest solution after the damage is done followed by a service done on the furnace.
We always tell this in writing and personally to the builder when he calls in for temp heat.He is told this before the job starts actually.
The problem Ive seen over the years is temporary heat is achieved by propane salamanders that produce moisture and wont allow paint,drywall mud etc. to dry quickly. The gen.contractor calls the heating Co. to start the furnace.
We have a couple of old unit heaters that we set up for temp heat and charge extra for that setup.

[ek]

This problem can be solved with 2 words.

MEDIA FILTER

Protects the equipment against sheetrock dust every time.

"Pigs get fat, Hogs get slaughtered"

[amickracing]

Not always.. granted a good filter is better than a crappy filter if they are going to run it anyway. But on an 80% furnace that draws combustion air from the front of the furnace (louvered door), it gets filled with dust too, and it's kinda hard to get a filter to stay on the front door :-)

[neophytes serendipity]

No one has addressed the real issue yet- the builder that demands the heat, and the contractor that will lose the work when he says "no" to a temp heat furnace start up.

Once again, the homeowner gets screwed. Actually, screwed twice- once on the low bid crappy install and again on that system choked with drywall dust.

I read in Snips a while back that there is supposedly a SMACNA "white paper" being worked up concerning early equipment start up.

[MikeJ]

Originally posted by ek
This problem can be solved with 2 words.

MEDIA FILTER

Protects the equipment against sheetrock dust every time.

"Pigs get fat, Hogs get slaughtered"

Not quite. The more efficient the filter, the more easily and quicker it gets plugged up, and, in the situation described, no one of the tradesman gives a pigs ask about changing the filter. So now you got a unit cycling on limit as well as collecting harmful byproducts of construction in every nook and cranny possible. I believe the filter only filters incoming return air thru the duct, no?

Does the filter keep the dust out of the inducer motor, the inshot burners, the wire contacts, etc? I don't think so.

also found this by typing in Construction dust "hvac" in a search enging:

http://www.smacna.org/pdf/management...up_Summary.pdf

[Edited by MikeJ on 12-11-2005 at 11:15 AM]