HVAC work = dusty film on everything?

[churchmouse]

OP.... Any attic work done recently? I have had way too many calls after the cable/phone company clown was in the attic and pulled/knocked return flex ducts off letting the system suck loose insulation into the system. Just asking for the poor sucker that usually has to fix the damage the other guys cause.

That makes some sense.

 

[GLOCKMAN23C]

That makes some sense.

It does. I told you about my dust issue, always had a grey dust on everything in the house. Well the air return is 3' away from my dryer. We always used decent filters, and always had grey dust. After you did my new install, I've noticed less dust. You did a better job sealing the ducts than the previous installer did 25 years ago.

 

[Dead Duck]

I am not an HVAC guy but I did work for a home builder for a time.
I was the guy that checked the progress of the homes from slab to the owners walk-thru and any valid repairs for a year after move in. I was always the first to start-up all the units in my homes.

Every single one had oil residue covering the components inside and they all needed to burn off.

Start-Up procedure -
-Open all the doors and windows.
-Turn on the downstairs heater.
-Turn on the upstairs heater.
-Warn any workers in the house that the detectors will be going off and you will smell something burning briefly.
-Climb up and watch the fire-up steps physically in the attic units.
-Make sure they installed proper exhaust duck through the roof. (Had a couple houses they missed. Popped my head up to a flame blasting my face)

Point is, new units can blow an oil layer all over the house and some smoke so it usually sets the detectors off. I've also had it happen after the HVAC guys finish doing repairs. Do they spray the components down with oil? I don't know but I've never had complaints of residue or film on anything. Repairing units after the owners are living there with all the furnishings was rare for us. First start-ups of course is a newly finished home with no furniture.

 

[Ingomike]

and if the fan switch was set to 'ON' and not to 'AUTO' as it should be......

And just why should the switch be set to "AUTO". It should not be. It should be set to "ON". Modern HVAC systems are built to recirculate the air in the home to even out the temperature in the home by reducing hot or cold spots. It should also reduce energy consumption while making the home more comfortable, particularly two story homes. My fan has not been off, other than for service, in 27 years.

 

[GREEN607]

And just why should the switch be set to "AUTO". It should not be. It should be set to "ON". Modern HVAC systems are built to recirculate the air in the home to even out the temperature in the home by reducing hot or cold spots. It should also reduce energy consumption while making the home more comfortable, particularly two story homes. My fan has not been off, other than for service, in 27 years.

I never said a word about OFF, Mike.

The fan switch on anything but a digital T-stat unit has a 3-way fan switch, OFF is in the center, AUTO is (usually) up or left, and ON is down or right. If you have the switch for the fan set to 'ON'....... the units fan will run 24/7. It has ALWAYS been that way!

That will run up a helluva electric bill.

 

[churchmouse]

I never said a word about OFF, Mike.

The fan switch on anything but a digital T-stat unit has a 3-way fan switch, OFF is in the center, AUTO is (usually) up or left, and ON is down or right. If you have the switch for the fan set to 'ON'....... the units fan will run 24/7. It has ALWAYS been that way!

That will run up a helluva electric bill.

OK this is getting deep now. No need to shout...
We run our fan in the on position when the temps get critical outside to even out the house and we heat with wood in the winter when temps fall to below 35*s.
In the years I have done this I have noticed that yes there is oil of the new units heat exchanger. It will burn off and it is gone quickly. Years ago this would set off the alarms from the smoke but these days it is just a slight odor. No detectable smoke of any kind. Just a smell. It dissipates very rapidly. We do 10 to 15 new systems a year so we see it all the time.
No we do not apply any oils to anything.

As to the fan. In discussing this with people who are far smarter than I am it is a wash. The fan draws its highest current at start up. 3 to 4 times the draw as to steady running. If you cycle the fan as to just running it in some of the new units it is a wash on the usage. An older belt drive I can see it costing maybe another $10 on the bill but again.....where does your daily driver get the best mileage.....stop and go or out on the highway running steady on the cruise control...???? Pretty much the same thing. Energy consumption. I get this argument all the time from folks. Once they try it, see the comfort gains, see very little if any increase in the energy bill.........

I have a cheese burger riding on this...

 

[churchmouse]

It does. I told you about my dust issue, always had a grey dust on everything in the house. Well the air return is 3' away from my dryer. We always used decent filters, and always had grey dust. After you did my new install, I've noticed less dust. You did a better job sealing the ducts than the previous installer did 25 years ago.

If you will remember we found a huge gap in the RA duct left there when the last up-grade was done. Glad it improved with the proper use of materials...

 

[churchmouse]

And just why should the switch be set to "AUTO". It should not be. It should be set to "ON". Modern HVAC systems are built to recirculate the air in the home to even out the temperature in the home by reducing hot or cold spots. It should also reduce energy consumption while making the home more comfortable, particularly two story homes. My fan has not been off, other than for service, in 27 years.

It is something I have preached especially 2 story homes with poor duct design. It does work.
My initial experience in the trades was Industrial/commercial with a bit of residential for the customers I serviced. Huge equipment on the industrial side. Some of it mind boggling. The residential came to be when I retired.... as that never seemed to happen. WE have seen it all. Some of my opinions are scaled down from that work. Smaller equipment but the applications and expected results are the same.

 

[Ingomike]

I never said a word about OFF, Mike.

The fan switch on anything but a digital T-stat unit has a 3-way fan switch, OFF is in the center, AUTO is (usually) up or left, and ON is down or right. If you have the switch for the fan set to 'ON'....... the units fan will run 24/7. It has ALWAYS been that way!

That will run up a helluva electric bill.

Ok, I'll fix it for you, my fan has been on the "ON" setting for 27 years, other than for service. As CM explained it does not result in noticeable differences in electric bills.

 

[churchmouse]

Ok, I'll fix it for you, my fan has been on the "ON" setting for 27 years, other than for service. As CM explained it does not result in noticeable differences in electric bills.

There is a school of thought as to prolonging the life of the blower motor as well. Up to temp and cruising not coming from locked rotor/static to speed pulling the wheel up with it multiple times a day. Les heat in the winding's.

A single phase 115V blower drive has to use a capacitor to generate a ghost 3rd phase to give the motor a boost off of static and direction. With out this "Jump" start so to speak the drive would just hum, get hot, trip out on the internal. When the capacitors fail this is the result and so many blower drives are replaced at expense not needed to the customer when a simple $10 capacitor would get it back on line. Also lack of maint. as to filters etc cause the wheels to load up with dirt and the cooling holes on the drive get blocked. Less air over the drive and the A/C coil will half life the equipment.

 

[JeepHammer]

NOT an HVAC guy,
We had a blower motor replaced and got dust all over the house for a couple months.
Finally cleaned the OLD duct work out and the dust stopped.

Turns out, the new motor wasn't damaged, and simply moved more air picking up the existing dust from decades of accumulation in the ducts.
Rattling things around changing motor probably didn't help the situation.
Ducts are some NASTY places, you won't believe the crap that comes out of them...

 

[Hoosierkav]

Ok--I called the HVAC company and their puzzler was puzzled, but offered to send out a tech to check the system.

We brainstormed some more and he asked, "Do you have a humidifier? One that uses tap water? Because those can get a mineral deposit on everything..."

So I looked up the humidifier's owner's manual, and, "ABOUT WHITE DUST: Use of high mineral content hard water may cause a white mineral residue to accumulate on surfaces
in the room near the humidifier. The mineral residue is commonly called “white dust.” The higher the mineral content (or, the harder your water is), the greater the potential for white dust. The white dust is not caused by a defect in the humidifier. It is caused only by minerals suspended in the water. The cartridge should be replaced every 30 – 40 fillings. The cartridge may need to be replaced more often if you are using very hard water. Replace the cartridge when you notice an increase in white dust build-up." We've had them for 2 years and haven't ever changed the cartridges, and the one downstairs runs 24/7 from the start of winter.

Occam's razor. Let's shut off the humidifiers and see what happens.

As for the rest of the discussion, you're mirroring discussions I've had with multiple HVAC folks over the years. Nearly verbatim

EDIT: I talked with my daughter and told her what I had discovered. "Oh, I knew that a while ago--the bedroom with the humidifier had the film but mine, without one, didn't. I just didn't tell anyone".

 

[ChristianPatriot]

Well there ya go.

 

[churchmouse]

Ok--I called the HVAC company and their puzzler was puzzled, but offered to send out a tech to check the system.

We brainstormed some more and he asked, "Do you have a humidifier? One that uses tap water? Because those can get a mineral deposit on everything..."

So I looked up the humidifier's owner's manual, and, "ABOUT WHITE DUST: Use of high mineral content hard water may cause a white mineral residue to accumulate on surfaces
in the room near the humidifier. The mineral residue is commonly called “white dust.” The higher the mineral content (or, the harder your water is), the greater the potential for white dust. The white dust is not caused by a defect in the humidifier. It is caused only by minerals suspended in the water. The cartridge should be replaced every 30 – 40 fillings. The cartridge may need to be replaced more often if you are using very hard water. Replace the cartridge when you notice an increase in white dust build-up." We've had them for 2 years and haven't ever changed the cartridges, and the one downstairs runs 24/7 from the start of winter.

Occam's razor. Let's shut off the humidifiers and see what happens.

As for the rest of the discussion, you're mirroring discussions I've had with multiple HVAC folks over the years. Nearly verbatim

Well looky looky.......That makes sense as I have heard of this in the past "BUT" the farther out I get from the past the harder it is to remember the past so the past stay as it was. The past.

 

[DoggyDaddy]

NOT an HVAC guy,
We had a blower motor replaced and got dust all over the house for a couple months.
Finally cleaned the OLD duct work out and the dust stopped.

Turns out, the new motor wasn't damaged, and simply moved more air picking up the existing dust from decades of accumulation in the ducts.
Rattling things around changing motor probably didn't help the situation.
Ducts are some NASTY places, you won't believe the crap that comes out of them...

I had a Groupon deal for duct cleaning last year, and I knew it had to have been years (probably 20 or more) since our ductwork was cleaned. The guy showed me the dirt that he got out of the ducts. I was expecting a LOT. It was less than I get just from vacuuming the carpets once a week. I'll never have that done again. Wasn't worth it, even with the "deal" from Groupon.

 

[JeepHammer]

I had a Groupon deal for duct cleaning last year, and I knew it had to have been years (probably 20 or more) since our ductwork was cleaned. The guy showed me the dirt that he got out of the ducts. I was expecting a LOT. It was less than I get just from vacuuming the carpets once a week. I'll never have that done again. Wasn't worth it, even with the "deal" from Groupon.

There was at least an inch of pet hair, dirt, coins, dead bugs, and everything else you can think of in ours.
That house was built in 1950 and the ducts were cleaned about 2001.
Apparently they didn't believe much in filters in 1950...

When we built, I used radiant floor heat, no duct work & no blower, warm floors in the winter.

 

[churchmouse]

I had a Groupon deal for duct cleaning last year, and I knew it had to have been years (probably 20 or more) since our ductwork was cleaned. The guy showed me the dirt that he got out of the ducts. I was expecting a LOT. It was less than I get just from vacuuming the carpets once a week. I'll never have that done again. Wasn't worth it, even with the "deal" from Groupon.

If you maintain a well fit filter the only real dirt you should ever see is in the return. The filter should be between the blower and the return.
When we fab up a proper return air box for a new unit the filter is well fit. Easy enough to access and the size is written on the cover.
The new Hi-Eff unit will move more air. It is part of the design. Like JH said, if the system is dirty you will see the results on the counter and table tops.