More air flow in bathroom

[Bill and Nancy]

I switched the supply lines around. The red line is now connected to the defuser under the bed from the right side of the furnace. It is a very short line about 3 feet in length from the furnace directly to the defuser. I disconnected it from the left side of the furnace and re connected it to the right side of the furnace. Then I shortened the other blue line by almost 2 1/2 feet and connected it to the left side of the furnace so that runs to the bathroom. The red line makes a tight 180 degree turn more than I would have liked  but that’s the amount of line that I had and it may provide a little resistance to the air flow which is a good thing. I’m  amazed at the difference  it made in the bath room. Its hard to calculate the difference but It’s at least 3 time as much heat coming  out of the bathroom defuser than before.  And the other two defusers seem to be putting out just as much air.  See video.

Bill

[John E Davies]

Cool! I mean warm! Is there enough room at the rear connection to use one or even two adjustable hard elbows? I fear for your flimsy flex duct…

https://www.homedepot.com/p/Master-Flow-4-in-90-Deg-Round-Adjustable-Elbow-B90E4/100033952

Do you have enough return air from the bathroom?

John Davies

Spokane WA

[Bill and Nancy]

8 hours ago, John E Davies said:

Cool! I mean warm! Is there enough room at the rear connection to use one or even two adjustable hardc elbows? I fear for your flimsy flex duct…

https://www.homedepot.com/p/Master-Flow-4-in-90-Deg-Round-Adjustable-Elbow-B90E4/100033952

Do you have enough return air from the bathroom?

John Davies

Spokane WA

Yes my original plan was to do that. But I wanted to see if it would even make a difference before I went through the extra effort . This took me about 10 minutes to swap the piping around to try it and it worked better than anticipated. Next step will be to clean things up a bit and  most likely run rigid pipe where possible.

Bill

[Mainiac]

Think we have to remember that the heat loss, from long pipes in the basement area, are what keeps pipes and tanks from freezing?

[Mainiac]

As you can see from the candle flame the return vent increases air flow. The inverse is true when the bathroom vent is on, with the door closed.

[Bill and Nancy]

 I would have never thought of putting it there. I would think it would be low to get the cold off the floor rather than the heat off the ceiling. But I also think its a tiny trailer and it doesn't make much difference its not like we are trying to efficiently heat and cool a 4,000 square feet house. The only reason I did what I did is it took me literally 10 minutes and I was curious to see  if it would make a difference.

I like the vent it looks like art, Nice Job

Bill

[CnC]

2 hours ago, Mainiac said:

Think we have to remember that the heat loss, from long pipes in the basement area, are what keeps pipes and tanks from freezing?

Maybe not so much if the air isn't moving through the pipe?

Charlie.

[GAP]

2 hours ago, Mainiac said:

As you can see from the candle flame the return vent increases air flow. The inverse is true when the bathroom vent is on, with the door closed.

Where did you source that vent?  It's exactly what I was looking for.  In my case, I vented the bathroom into the space below the front dinette seat.  Also added a 4" return in the rear face of the same seat which I use to tweak air flow coming from the bathroom as too much would reverse exhaust venting from my composting toilet.  That same adjustable vent cover would be great for the return vent under the seat.

[Mainiac]

Where did you source that vent?

think it was a "Sea Dog" 4" SS butterfly vent. Vent Master,  if I remember right. In my application I used the same vent inside and out. I was going to use a non adjustable inside, but the holes did not match up. Didn't want moisture able to get into a wood core wall, which that wall is (at least in a 2017 model).

[Mainiac]

9 hours ago, Bill and Nancy said:

 I would have never thought of putting it there. I would think it would be low to get the cold off the floor rather than the heat off the ceiling. But I also think its a tiny trailer and it doesn't make much difference its not like we are trying to efficiently heat and cool a 4,000 square feet house. The only reason I did what I did is it took me literally 10 minutes and I was curious to see  if it would make a difference.

I like the vent it looks like art, Nice Job

Bill

Thanks. We put it up high so that any chance of stray water wouldn't get into it. In our year the wall is wood core. We did seal the core before screwing them together...

[Mainiac]

Our original thought for the vent, was the bathroom exhaust fan. If you go into the bathroom, turn on the exhaust, and then close the door you can hear the fan struggle hard to work. Open the door and you can literally hear the fan relax. If this is the case there must be a negative pressure (vacuum) situation going on.

So, thinking the inverse might also be true, came the idea for the vent. Thinking that with the door closed, like when using the bathroom, there would be a positive pressure when the heater fan was blowing. So the vent would allow the heat duct to "relax" and allow the air to get out and to the return air vent, hence increasing the heat flow to the bathroom. As you can see by the candle flame movement there certainly is air flow.

We did restrict the air flow to the duct opening under the bed so that that air did not go out and immediately go into the return. We think the bathroom is a lot warmer in cool weather. We could have done the same thing by leaving the bathroom door open, as some do, but find that inconvenient while using the dinette.

[Chukarhunter]

I swapped my supply flex ducts around at the furnace exactly as you did.  I also improved on the 180 degree "crushed" flex duct turn at the same time.  I could not find any adjustable hard elbows that would work as John suggests so I used a hard flexible dryer duct that is very short from the package, almost like rigid duct, but is expandable and bendable.  I used all of it without expanding it beginning with a large 15 inch diameter 180 degree turn at the furnace then ran it as far forward as it would go without expanding it.  It almost reached the diverter and then like you, I shortened the existing flex duct and clamped it and taped it to the new aluminum duct.  As you discovered, switching the duct runs around at the furnace increases the air flow to the bathroom but adding the lazy aluminum duct for the hard turn made for a noticeable additive increase in air flow forward as well.

 

[Bill and Nancy]

2 hours ago, Chukarhunter said:

I swapped my supply flex ducts around at the furnace exactly as you did.  I also improved on the 180 degree "crushed" flex duct turn at the same time.  

I plan to do something like you suggest I was just trying it out to see what effect it would have before I got carried away. If and when I change out the duct I may also put the splitter in the line feeding the two vents under the bed rather than the duct that feeds the bathroom. Providing  a straight shot to the bathroom, I think that will also improve the overall air flow. I’m also thinking of putting a butterfly vent in the upper left corner of the bathroom door like mainiac did not so much for heating but  to improve ventilation when using the shower, I like his idea. We tend to camp in colder weather and opening the window when using the shower tends to get rather chilly when it’s below freezing out side. 
 

Bill

[Geronimo John]

This is why I like our Owner's Forum, different ideas on how each owner has improvements for their trailer.

I am 100% in the "Increase air flow to the Bathroom" team.  I like both Maniacs' high adjustable vent, and the low vent to the basement proposed by Rivernerd. 

I really like the idea of adjustable vents for both.  Summer, use only the high vent to avoid putting mosture into the basement.  Cold conditions use only the low vent to help heat that area a bit.

GJ.     

[Chukarhunter]

14 hours ago, Bill and Nancy said:

I may also put the splitter in the line feeding the two vents under the bed rather than the duct that feeds the bathroom. Providing  a straight shot to the bathroom, I think that will also improve the overall air flow.

I am a fellow cold weather camper and considered doing that as well but decided that doing so would result in insufficient total free air flow from the furnace likely leading to furnace heat exchanger overheating and short-cycling of the furnace.  To work properly, the manual says the furnace needs a minimum of 25 sq. inches of unobstructed supply duct airflow.  A 4 inch flex duct has 12.56 sq. inches of airflow as it leaves the furnace.  Since there are only two supply ducts from the furnace, both must be completely unobstructed to achieve 25 sq. inches of unobstructed airflow.

All duct work creates friction and turbulence which reduces the free flow of air.  Rigid duct minimizes restriction of airflow but the flimsy flex duct used in the Oliver really reduces airflow in anything but short absolutely straight runs.  Dedicating one 4 inch duct to a long run to to the bathroom would cause such a restriction that the furnace would be subject to short cycling and poor heating performance.  I am sure that is why Oliver put the splitter into the long duct run to the bathroom so it feeds two registers, one being closer to the furnace.  To further complicate things, in my LE II, Oliver put a reducer behind the bathroom register that necks it down from a 4 inch duct to a 3 inch duct further restricting airflow into the bathroom.  They may have done this to make it feel like there was more air blowing into the bathroom (higher velocity but lower volume).  I don't thing changing this from a 3 inch to a 4 inch would make much difference though, given the long duct run to the bathroom.

I really wanted to turn my bathroom run into a straight, untapped duct run to the bathroom (i.e., eliminate the splitter) but determined it would not be acceptable without adding a third duct run off of the furnace, but that is next to impossible to do in my LE II, given the way Oliver installed the furnace in a vertical orientation.  The furnace can be installed vertically or on its side.  If Oliver had installed the furnace on its side, it would have been easy to run a third duct off of the furnace. It is not feasible to make that change now.

I think probably the best that can be done now is to add a return air vent to the bathroom and add ventilation between the bathroom and main cabin as you are planning.  I am getting ready to add a return vent to the bathroom in my LE II.  I will probably put it in the recessed front of the vanity behind the towel bar, so that return air will directly warm the plumbing under the bathroom sink. 

 

[bhncb]

What's interesting is why Oliver changed the duct routing, apparently when they reversed the furnace and hotwater heater locations. The routing changes Bill and Nancy made, as described and shown in the two pictures, is exactly how it used to be.

]

 

[Rivernerd]

1 hour ago, Chukarhunter said:

I am getting ready to add a return vent to the bathroom in my LE II.  I will probably put it in the recessed front of the vanity behind the towel bar, so that return air will directly warm the plumbing under the bathroom sink. 

I encourage you to place your new return air vent in the wall between the toilet and the front dinette seat, as shown in the attached photo.  This location enables return air to flow through the street side bottom of the trailer, under the battery box and eventually back to the furnace on the curb side.  To be most effective, return air vents need a minimally-obstructed path back to the furnace.  A return air vent in the recessed front of the vanity would have a quite a tortuous path back to the furnace. 

[Geronimo John]

7 hours ago, Geronimo John said:

I like both Maniacs' high adjustable vent, and the low vent to the basement proposed by Rivernerd.

Yep.  That sounds exactly like the wonderful idea you posted previously.  🙂

GJ  

[CnC]

21 hours ago, bhncb said:

What's interesting is why Oliver changed the duct routing, apparently when they reversed the furnace and hotwater heater locations.

I would be VERY interested in knowing WHY they made the change.

Charlie.

[Jason Essary]

I requested that production swap the furnace & water heater locations because the furnace ducting was running right over the top of the water heater bypass valve. This made locating the valve difficult for new owners as well as having to move the duct aside with the potential to tear it. Hopefully this change has made it better for access and does not cause any issues. 

I have also requested the return air vents as well and they did start putting a return vent in the bath where the air can return below the dinette about a year ago. They are still working on getting one placed in the closet which should be one on the top & one on the bottom for better air circulation through that area. The return air vents is something that can be easily added on older models if you choose to. 

 

[mossemi]

Jason,  Thank you for the update and clarification!  It is always good to hear explanations concerning changes to Oliver Travel Trailer production from the service department.

Mossey

[SeaDawg]

6 minutes ago, mossemi said:

Jason,  Thank you for the update and clarification!  It is always good to hear explanations concerning changes to Oliver Travel Trailer production from the service department.

Mossey

👍👍👍

[Mainiac]

2 hours ago, JEssary said:

They are still working on getting one placed in the closet which should be one on the top & one on the bottom for better air circulation through that area

The vents in the closet, will it be vented to the bath or the main cabin? The main purpose of venting the closet? Is it to warm it up in there? To change the air is a commendable goal, just have never heard any one say that to vent that space would be nice. Is it thought to accomplish this, with one high and one low, by using the thermo siphon principle? Or to take advantage of the forced air from the bathroom heat duct?

I would love to see a small waste basket installed half in/half out of the closet door. That would make it accessible from both inside and outside. Maybe the vent could be combined with this goal?

[2008RN]

On 1/18/2023 at 8:37 PM, John E Davies said:

Cool! I mean warm! Is there enough room at the rear connection to use one or even two adjustable hard elbows? I fear for your flimsy flex duct…

https://www.homedepot.com/p/Master-Flow-4-in-90-Deg-Round-Adjustable-Elbow-B90E4/100033952

Do you have enough return air from the bathroom?

John Davies

Spokane WA

  John ,et. al.

I bought two of the suggest elbows and they are little bit of a tight fit getting by the water line once past the line everything slid in easily. The only problems I had was the vent tube from the defuser under the bed was a couple of inches short to make it to the rear outfit with the elbows on.  I have to get a replace the tube and make it about 4-6 inches long.   I hooked everything up above the access panels and then just slid them in place. This is a picture before I slid it in.  

[Patriot]

Jason,
Thank you for the updates on the new  model Olivers changes and how some of these updates can be retrofit on older models as well. 
We look forward to seeing you in May when we swap out our Dometic AC for the Truma Aventa,

Patriot 🇺🇸