Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 05-07-2024, 02:47 PM   #1
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Is your furnace as dangerous as mine?

If you have relatively new AS and a digital air quality sensor (e.g., Mila, AirThings, etc.), please help me figure out if there is something wrong with my 2022 Flying Cloud furnace or if we are all being exposed to terrible air when our furnaces are running.

Like you, my CO sensor is NOT going off when I run my furnace. However, I have run some tests with three different air quality meters, and I find that running the furnace creates dangerous air quality. In one test, in an empty trailer with windows/door closed, I see:

1. PM10 - goes from 0 and continues to climb as long as the furnace runs. In one test, it exceeds 200 (ug/m3) in 30 minutes.

2. PM2.5 - goes from 0 and continues to climb as long as the furnace runs. In one test, it exceeds 150 (ug/m3) in 30 minutes.

3. PM1.0 (the most damaging PM type as it enters the bloodstream) - goes from 0 and continues to climb as long as the furnace runs. In one test, it exceeds 100 (ug/m3) in 30 minutes.

4. CO2 (**tested in empty trailer**) - goes up from background of 430ppm and continues to climb as long as furnace runs. In one test, gets to 530ppm in 30 minutes.

5. VOC - This also goes up, but since increasing temperatures also increase the VOC off-gassing of furniture, I don't want to get into how to differentiate combustion VOC from furniture VOC just yet.

All of the above are byproducts of propane burned with sufficient oxygen. So, is combustion air leaking into my trailer? In any case, none of this is good for you and according to the literature the PM levels are very unhealthy.

There is no CO produced when propane is burned with sufficient oxygen, so that explains no CO alarm.

If you have relatively new AS and a digital air quality sensor (e.g., Mila, AirThings, etc.), what do you see?

Thank you so much!!



Edit:
Other notes:
1. Running the above test with the heat pump to same temperatures does not increase CO2, PM1, PM2.5, PM10 at all. (I understand that the duct work is different.)

2. Running the above furnace test with a HEPA air filter running full blast does not change the PM results much while the furnace is running, but the PM goes down a lot faster once furnace is turned off with the filter on vs. off. In other words, the furnace PM creation overwhelms the HEPA filter.

3. If you are broadly in the Albany, NYC, Philly area, I am happy to come to you to test your late model AS for you with three different digital sensors!
rufusd7 is offline   Reply With Quote
Old 05-07-2024, 03:36 PM   #2
Rivet Master
 
Al and Missy's Avatar
 
2002 30' Classic S/O
Fleming Island , Florida
Join Date: Nov 2013
Posts: 4,708
First thing I would do is ensure that the intake area for the furnace is clean. Mine is just an open area under the galley sink cabinet and it collects all kinds of dirt, dust, and pet hair.


The CO2 reading is disconcerting. The propane is burned in, and the combustion products are vented through, one side of a heat exchanger. Cabin air is pushed through the other side by the fan. Older exchangers can rust and leak. If you could pressurize it with a compressor from the exhaust fitting you could check for leaks into the ducts. Barring that, there could be a leak drawing the exhaust back into the cabinet and into the cabin air stream. Make sure the intake to the furnace blower is well sealed to the inlet area (under the cabinet if like mine).
__________________
ďYou cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
Al and Missy is offline   Reply With Quote
Old 05-07-2024, 03:55 PM   #3
Rivet Master
 
Wayne&Sam's Avatar
 
2014 25' Flying Cloud
Cuddebackville , New York
Join Date: May 2007
Posts: 4,395
Images: 21
We've been using our 2007, and then our 2014 Flying Cloud for 18 years. I'm now dead, so I can't post a comment.
__________________
2014 25' Flying Cloud Rear Twin
2019 Ford Expedition Platinum
Wayne&Sam is offline   Reply With Quote
Old 05-07-2024, 04:00 PM   #4
Rivet Master
 
2002 19' Bambi
Lafayette , California
Join Date: May 2005
Posts: 1,585
Under the assumption that PM is particulate matter, increases when the furnace is running are to be expected. The furnace is forced air and the circulating air will stir up almost anything on the various inner surfaces of the trailer.

I suggest making sure your trailer is well ventilated when you are inside it.

Tim
Tim A. is offline   Reply With Quote
Old 05-07-2024, 04:04 PM   #5
Rivet Master
 
2019 22' Sport
High River , Alberta
Join Date: Aug 2006
Posts: 1,236
The CO2 level by itself is not an issue. Ambient is 430, hazardous is 4,000 plus. However, it does point to combustion air being drawn back into the trailer.

The real concern is particulate matter which is going to be the amount of soot - carbon - created by combustion. Why is it being drawn in?

Also, how does this compare to using the stovetop or oven?

I would expect a rusted out or leaking heat exchanger to create measurable CO due to an uncontrolled air-fuel ratio.
AlbertF is offline   Reply With Quote
Old 05-08-2024, 06:36 AM   #6
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by Al and Missy View Post
First thing I would do is ensure that the intake area for the furnace is clean. Mine is just an open area under the galley sink cabinet and it collects all kinds of dirt, dust, and pet hair.


The CO2 reading is disconcerting. The propane is burned in, and the combustion products are vented through, one side of a heat exchanger. Cabin air is pushed through the other side by the fan. Older exchangers can rust and leak. If you could pressurize it with a compressor from the exhaust fitting you could check for leaks into the ducts. Barring that, there could be a leak drawing the exhaust back into the cabinet and into the cabin air stream. Make sure the intake to the furnace blower is well sealed to the inlet area (under the cabinet if like mine).

Thank you for the great response. The CO2 is disconcerting. While the CO2 levels are not unsafe, it points to combustion air making its way into the cabin along with the other unsafe stuff. Dometic says no combustion air should make its way into the unit, so I shouldn't just accept this. I will check into items you say and report back.
rufusd7 is offline   Reply With Quote
Old 05-08-2024, 06:37 AM   #7
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by Wayne&Sam View Post
We've been using our 2007, and then our 2014 Flying Cloud for 18 years. I'm now dead, so I can't post a comment.

I hate to break it to you, but I have some bad news. You aren't dead.
rufusd7 is offline   Reply With Quote
Old 05-08-2024, 06:40 AM   #8
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by Tim A. View Post
Under the assumption that PM is particulate matter, increases when the furnace is running are to be expected. The furnace is forced air and the circulating air will stir up almost anything on the various inner surfaces of the trailer.

I suggest making sure your trailer is well ventilated when you are inside it.

Tim

Thank you! I agree with the particulate matter comment - one should expect a PM increase when starting the fan, but the PM continues to climb linearly even with a beefy HEPA filter running. The air should get cleaner over time, not worse. (If I put the filter in a room with high PM, it clears it relatively quickly. So, I know it works.) So, it appears to me that PM is being generated, not just moved around. I will try to run just the furnace circulation fan with no combustion. If the PM doesn't go up, would you agree that it is combustion air making its way into the living space?
rufusd7 is offline   Reply With Quote
Old 05-08-2024, 06:44 AM   #9
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by AlbertF View Post
The CO2 level by itself is not an issue. Ambient is 430, hazardous is 4,000 plus. However, it does point to combustion air being drawn back into the trailer.

The real concern is particulate matter which is going to be the amount of soot - carbon - created by combustion. Why is it being drawn in?

Also, how does this compare to using the stovetop or oven?

I would expect a rusted out or leaking heat exchanger to create measurable CO due to an uncontrolled air-fuel ratio.

I agree that the CO2 levels are not dangerous, but it seems to prove that combustion air is coming into the living space along with the PM, etc.

I like your idea of comparing to stovetop. I will do that and report.

The heat exchanger looks good by visual inspection.
rufusd7 is offline   Reply With Quote
Old 05-08-2024, 06:56 AM   #10
4 Rivet Member
 
2019 28' Flying Cloud
Broward , Florida
Join Date: Feb 2023
Posts: 417
CO2 concentrations are typically higher indoors. One reason is that when humans exhale, their breath is about 4% CO2 (compared to 0.04% outside). There is no cause for concern. NASA has set the limits for CO2 in the International Space Station at 5250 PPM.

The particulate matter is likely coming from dust in the ductwork.
Andy543 is offline   Reply With Quote
Old 05-08-2024, 08:03 AM   #11
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by Andy543 View Post
CO2 concentrations are typically higher indoors. One reason is that when humans exhale, their breath is about 4% CO2 (compared to 0.04% outside). There is no cause for concern. NASA has set the limits for CO2 in the International Space Station at 5250 PPM.

The particulate matter is likely coming from dust in the ductwork.

Thank you for the response!

As I outlined, the CO2 concentration *increased* in an empty trailer (no humans) when the furnace was activated. I agree that these levels aren't a concern, but it suggests that combustion air is entering the unit (a concern given everything else that comes with it).

As I outlined, the duct work can have PM that gets kicked up on activation, but they should not indefinitely and continuously generate more in a way that overwhelms the HEPA filter indefinitely until the moment the furnace stops.
rufusd7 is offline   Reply With Quote
Old 05-08-2024, 09:37 AM   #12
Rivet Master
 
2012 23' FB International
Woodstock , Ontario
Join Date: Aug 2014
Posts: 1,440
I hav had a propane alarm go off when running a furnace with Lowe battery voltage. The plastic duct work gassed off with the hotter air being delivered due to slower fan speed
I wonder if the additional CO2 was due to you in the enclosed trailer. Test again without the furnace running
JCWDCW is offline   Reply With Quote
Old 05-08-2024, 03:49 PM   #13
Half a Rivet Short
 
2017 30' Classic
2022 Interstate 24X
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 15,908
Hi

When the furnace is running, it's pulling air in from "over there" and blasting it out "over here". In a lot of cases the intake is close to the floor. Like it or not, the floor is dirty. The same is true of the inside of the ducts and the rest of the trailer. They are dust magnets. The longer you blow air, the more dust you get flying around.

Simple answer (if this really bugs you): do a deep clean of the whole trailer *and* the ducts. Then repeat the test.

Bob
uncle_bob is offline   Reply With Quote
Old 05-09-2024, 05:41 AM   #14
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by JCWDCW View Post
I hav had a propane alarm go off when running a furnace with Lowe battery voltage. The plastic duct work gassed off with the hotter air being delivered due to slower fan speed
I wonder if the additional CO2 was due to you in the enclosed trailer. Test again without the furnace running

Thank you for the response! As I mentioned in the post, I was not in the trailer during testing. If the particulate matter is from the plastic duct work, we should all replace our duct work. I haven't measured air this bad since the smoke wafted down from the Canada fires.

I will try the fan only. Thanks!
rufusd7 is offline   Reply With Quote
Old 05-09-2024, 05:47 AM   #15
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by uncle_bob View Post
Hi

When the furnace is running, it's pulling air in from "over there" and blasting it out "over here". In a lot of cases the intake is close to the floor. Like it or not, the floor is dirty. The same is true of the inside of the ducts and the rest of the trailer. They are dust magnets. The longer you blow air, the more dust you get flying around.

Simple answer (if this really bugs you): do a deep clean of the whole trailer *and* the ducts. Then repeat the test.

Bob

Thank you for the response! The door was closed and the HEPA air filter was was running. The air is from "over there" and blasting "over here" when things are working, so it could be a compromised combustion chamber or something wrong with the duct work pulling outside air near the exhaust inside. I don't see how this explains the increase in CO2 in an empty trailer. In any case, I will try fan only to rule out duct work dust. Thanks!
rufusd7 is offline   Reply With Quote
Old 05-09-2024, 01:44 PM   #16
3 Rivet Member
 
2021 16' Caravel
Fullerton , California
Join Date: Dec 2020
Posts: 118
Quote:
Originally Posted by Wayne&Sam View Post
We've been using our 2007, and then our 2014 Flying Cloud for 18 years. I'm now dead, so I can't post a comment.
Bummer!
NeahBay is offline   Reply With Quote
Old 05-10-2024, 06:35 AM   #17
2 Rivet Member
 
Kingston , New York
Join Date: May 2021
Posts: 63
Quote:
Originally Posted by JCWDCW View Post
I hav had a propane alarm go off when running a furnace with Lowe battery voltage. The plastic duct work gassed off with the hotter air being delivered due to slower fan speed
I wonder if the additional CO2 was due to you in the enclosed trailer. Test again without the furnace running

Exploring this further: We may have a design flaw. The furnace literature explicitly says that the ducts must be rated for 200 degrees F or better. Most plastic ducts I have seen are only rated to 180 degrees F. I haven't had a chance to check the make/brand of the ducts in my unit, but if not rated for these temps, it could be a fire hazard in addition to a health issue.
rufusd7 is offline   Reply With Quote
Old 05-10-2024, 07:36 AM   #18
Site Team
 
richard5933's Avatar

 
1994 25' Excella
Waukesha , Wisconsin
Join Date: Sep 2020
Posts: 5,865
Images: 5
A couple of outside the box thoughts on this...

When you run the furnace, the electrical side of it is powered by the 12vdc system. In other words, power is drawn from the batteries to spin the fan and power the controls. At the same time, the battery converter/charger is going to ramp up charging to keep the batteries topped off. It is possible that the rise in CO2 is being caused by the batteries if they are housed inside the trailer or are in some way sharing the air inside the trailer. Not likely to be the problem on newer trailers with outside battery boxes but there are older trailers like mine with battery boxes sitting inside the nose of the trailer as well as owner-modifications bringing the batteries inside.

There are other things that can create an increase in CO2, like cooking dust, bugs, and other things which might be on/in the furnace. Have you checked the furnace to see if it's in need of cleaning? The outside as well as the inside?

Has the trailer been to a high-dust event, like Burning Man?

Has the furnace flame been inspected for color and carbon buildup on the burner? Has the combustion chamber been checked for leaks?
__________________
Richard
11018
1994 Excella 25 'Gertie' Follow the build on Gertie!
1999 Suburban LS 2500 w/7.4L V8 'Bert'
1974 GMC 4108a - Custom Coach Land Cruiser 'The Bus' (Sold)
richard5933 is online now   Reply With Quote
Old 05-10-2024, 08:06 AM   #19
Half a Rivet Short
 
2017 30' Classic
2022 Interstate 24X
Carlisle , Pennsylvania
Join Date: May 2017
Posts: 15,908
Quote:
Originally Posted by rufusd7 View Post
Thank you for the response! The door was closed and the HEPA air filter was was running. The air is from "over there" and blasting "over here" when things are working, so it could be a compromised combustion chamber or something wrong with the duct work pulling outside air near the exhaust inside. I don't see how this explains the increase in CO2 in an empty trailer. In any case, I will try fan only to rule out duct work dust. Thanks!
Hi

Did you change the temperature in the trailer as part of the process? Adsorption and desorption of CO2 is temperature dependent. You have a lot of "stuff" in the trailer that is quite happy to lock up or release CO2. Since the rates for each process can be vastly different, working out all those details .... yikes .....

These trailers are *far* from air tight. Start looking here and there. You have a *lot* of holes in the floor. None of them are "air sealed". That's a good thing if you turn on vent fan .... It does mean that you are alway going to have some air exchange between the trailer and the outside world. It's not an "air tight jug".

These furnaces are not a very complex sort of thing. In the amount of time we've all spent typing about this, a quick eyeball inspection would go a long ways towards a "confirm or deny" of a problem with your unit.

Bob
uncle_bob is offline   Reply With Quote
Old 05-10-2024, 08:08 AM   #20
Site Team
 
richard5933's Avatar

 
1994 25' Excella
Waukesha , Wisconsin
Join Date: Sep 2020
Posts: 5,865
Images: 5
Did the CO2 ever get above 530?
__________________
Richard
11018
1994 Excella 25 'Gertie' Follow the build on Gertie!
1999 Suburban LS 2500 w/7.4L V8 'Bert'
1974 GMC 4108a - Custom Coach Land Cruiser 'The Bus' (Sold)
richard5933 is online now   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Are your insurance rates going up like mine? djb75 Insurance & Claims 36 10-04-2023 10:18 AM
Is using the furnace while we sleep dangerous? cantdrv55 Our Community 39 12-17-2014 09:57 AM
dangerous tongue jack kooblekidz Jacks, Stabilizers, Lifting and Leveling 4 08-15-2005 02:31 PM
Dangerous for Dogs? Edie The Pet Forum 11 05-20-2004 12:28 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 02:05 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.