Reply
 
Thread Tools Display Modes
Old 08-09-2016, 08:29 AM   #11
Head Rambler
 
Join Date: Mar 2008
Location: Southwest Alabama
Posts: 3,481
Do you mind doing a little work to see if we can figure this out?

1) Measure from the bottom of the bottom vent to the top of the top vent.

2) Take a picture from the bottom vent looking up toward the fans.

3) If you see a baffle of any sort measure the distance between the edge of it and the absorber coils. It should be about an inch.

4) If you can, measure the distance from the floor to the vent fans. it should be 44". You may have to go about it backwards by measuring up to the top vent and back down to the fans and subtracting.

I see no where in the service manual that says anything about blocking off part of the upper vent. I'm not sure that's hurting you much, but it certainly could be.

I do see on page 35, an air channel that extends up about half way or a little more above the top vent opening. Maybe that's what they were trying to accomplish.
__________________

__________________
Salem 29RKSS Pushing a 2500 Mega-Cab CTD!
Gotta go campin!
Bama Rambler is offline   Reply With Quote
Old 08-09-2016, 08:35 AM   #12
Senior Member
 
5picker's Avatar
 
Join Date: Aug 2015
Location: South Western PA
Posts: 2,916
Quote:
Originally Posted by jstaffon View Post
What are the boards for in the upper vent? They must have some function. I was thinking of removing them but didn't want to ruin the original installation. Is the relay you wired the fans to in the lower vent area? Do you have the model numbers or pictures of the fans you installed?
I never got a good answer from the factory for their purpose of the boards.
A fellow who I consider 'in the know' said they help prevent cavitation of the air at the top of the box from the factory fans. Your guess is a good as any.

Yes, the relay attached to the right rear lower of the refrigerator is where I got 12v. It supplies the voltage for the factory fans.

I didn't take pictures as there are LOTS of discussions (here and elsewhere) about adding fans to a slide-out mounted refrigerator with photos. I could take some if you feel necessary.

The objective with the fans in a slide-out mounted refrigerator is to create enough air flow to simulate the natural air flow (heat rises) obtained when a refrigerator has a roof mounted top vent. You don't want too much though where it disturbs the flame mixture when on propane.

One fan at the bottom blowing up and one at the top, blowing out the upper side vent, does the trick.

With this set-up it should be able to hold a sheet of paper to the outside of the lower grill when they are on.

There are TONS of fans available on the 'net. Pick your favorite flavor.
**HERE** is one I used.
__________________

__________________
_________________________________________
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel
Ford F-Series SCREW 4x4
TST Tire Monitor - Sinemate 3500w Gen.
2016 Nights Camped = 46
5picker is offline   Reply With Quote
Old 08-09-2016, 08:49 AM   #13
Senior Member
 
Join Date: Jun 2012
Posts: 4,919
Air doesn't cavitate; water does.

"Cavitation is the formation of vapour cavities in a liquid – i.e. small liquid-free zones ("bubbles" or "voids") – that are the consequence of forces acting upon the liquid."

Maybe he meant "stagnate?"
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybid (2012-2015)

2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
rockfordroo is online now   Reply With Quote
Old 08-09-2016, 09:14 AM   #14
Senior Member
 
5picker's Avatar
 
Join Date: Aug 2015
Location: South Western PA
Posts: 2,916
Quote:
Originally Posted by rockfordroo View Post
Air doesn't cavitate; water does.

"Cavitation is the formation of vapour cavities in a liquid i.e. small liquid-free zones ("bubbles" or "voids") that are the consequence of forces acting upon the liquid."

Maybe he meant "stagnate?"
Just using his words.
Maybe I should have just kept my mouth shut.
__________________
_________________________________________
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel
Ford F-Series SCREW 4x4
TST Tire Monitor - Sinemate 3500w Gen.
2016 Nights Camped = 46
5picker is offline   Reply With Quote
Old 08-09-2016, 04:38 PM   #15
Junior Member
 
jstaffon's Avatar
 
Join Date: Feb 2016
Location: Idaho
Posts: 27
Quote:
Originally Posted by Bama Rambler View Post
Do you mind doing a little work to see if we can figure this out?

1) Measure from the bottom of the bottom vent to the top of the top vent.

2) Take a picture from the bottom vent looking up toward the fans.

3) If you see a baffle of any sort measure the distance between the edge of it and the absorber coils. It should be about an inch.

4) If you can, measure the distance from the floor to the vent fans. it should be 44". You may have to go about it backwards by measuring up to the top vent and back down to the fans and subtracting.

I see no where in the service manual that says anything about blocking off part of the upper vent. I'm not sure that's hurting you much, but it certainly could be.

I do see on page 35, an air channel that extends up about half way or a little more above the top vent opening. Maybe that's what they were trying to accomplish.
I'll have to take those measurements the next time I bring the camper home. It's in storage right now and I can't access that side of the camper.

Regarding the boards, I think I understand. The boards are forcing all of the air upward through the fins instead of letting some of the air short-circuit the path and exit the upper vent before passing through the fins. I also think I can install a baffle above the fins that curves and directs the air out through the vent. Right now it's a 90 degree angle at the top of the vent. I'm also talking to Dometic to see what they recommend. I would hate to void any warranty at this point.
__________________
2013 GMC Sierra 2500 HD, Duramax
2016 Forest River Rockwood 8299BS
jstaffon is offline   Reply With Quote
Old 08-09-2016, 05:02 PM   #16
Junior Member
 
jstaffon's Avatar
 
Join Date: Feb 2016
Location: Idaho
Posts: 27
Quote:
Originally Posted by rockfordroo View Post
Air doesn't cavitate; water does.

"Cavitation is the formation of vapour cavities in a liquid i.e. small liquid-free zones ("bubbles" or "voids") that are the consequence of forces acting upon the liquid."

Maybe he meant "stagnate?"
Yeah, I knew what he meant though. He meant to say turbulent air flow as apposed to laminar air flow. I think if I install a baffle at the top, I'll get laminar air flow all the way up through the fins from the boards and then directed out the vent by the baffle. Thanks!
__________________
2013 GMC Sierra 2500 HD, Duramax
2016 Forest River Rockwood 8299BS
jstaffon is offline   Reply With Quote
Old 08-09-2016, 05:05 PM   #17
Junior Member
 
jstaffon's Avatar
 
Join Date: Feb 2016
Location: Idaho
Posts: 27
Quote:
Originally Posted by 5picker View Post
I never got a good answer from the factory for their purpose of the boards.
A fellow who I consider 'in the know' said they help prevent cavitation of the air at the top of the box from the factory fans. Your guess is a good as any.

Yes, the relay attached to the right rear lower of the refrigerator is where I got 12v. It supplies the voltage for the factory fans.

I didn't take pictures as there are LOTS of discussions (here and elsewhere) about adding fans to a slide-out mounted refrigerator with photos. I could take some if you feel necessary.

The objective with the fans in a slide-out mounted refrigerator is to create enough air flow to simulate the natural air flow (heat rises) obtained when a refrigerator has a roof mounted top vent. You don't want too much though where it disturbs the flame mixture when on propane.

One fan at the bottom blowing up and one at the top, blowing out the upper side vent, does the trick.

With this set-up it should be able to hold a sheet of paper to the outside of the lower grill when they are on.

There are TONS of fans available on the 'net. Pick your favorite flavor.
**HERE** is one I used.
Would you recommend attaching the fans to the vent covers on both the upper and lower? ... I've seen drawings with a fan attached to the upper vent cover but not seen pictures of where to attach the fan. Sorry to be so inquisitive..
__________________
2013 GMC Sierra 2500 HD, Duramax
2016 Forest River Rockwood 8299BS
jstaffon is offline   Reply With Quote
Old 08-09-2016, 05:07 PM   #18
Junior Member
 
jstaffon's Avatar
 
Join Date: Feb 2016
Location: Idaho
Posts: 27
Quote:
Originally Posted by 5picker View Post
Just using his words.
Maybe I should have just kept my mouth shut.
I knew what you meant...
__________________
2013 GMC Sierra 2500 HD, Duramax
2016 Forest River Rockwood 8299BS
jstaffon is offline   Reply With Quote
Old 08-09-2016, 07:25 PM   #19
Senior Member
 
5picker's Avatar
 
Join Date: Aug 2015
Location: South Western PA
Posts: 2,916
Quote:
Originally Posted by jstaffon View Post
Would you recommend attaching the fans to the vent covers on both the upper and lower? ... I've seen drawings with a fan attached to the upper vent cover but not seen pictures of where to attach the fan. Sorry to be so inquisitive..
You could, I chose not to but have read where many have. The down side would be you'd almost need to put a connector in the wiring so if you wanted to remove the vet cover you could unplug the attached fan. Simple enough.

I cut a hole and mounted mine to the boards. (see modification of your photo for placement)

I figured the extra couple inches away from the vent surface would allow more air flow than mounting directly to the vent cover since there is a considerable amount of blockage to the fan from the solid horizontal bars molded in the vent cover if the fan was mounted directly to it.

I mounted it off to the side instead of centered in case I needed to mount a second one. Once installed and seen how well it worked, I didn't feel the need for two at the top.

I placed my lower fan flat on a couple 1" standoffs so the air blows up the back side of the fridge pulling in air from the lower vent cover.
The top fan is vertical so it blows out the vent cover.

I'd snap you some photos but my slide is currently out and is only about 8" from the side of my garage outside wall and I can't squeeze in there to take pictures. I will do it next time I put the slide in.
Attached Thumbnails
Click image for larger version

Name:	upper vent.jpg
Views:	31
Size:	312.2 KB
ID:	116768  
__________________
_________________________________________
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel
Ford F-Series SCREW 4x4
TST Tire Monitor - Sinemate 3500w Gen.
2016 Nights Camped = 46
5picker is offline   Reply With Quote
Old 08-09-2016, 07:30 PM   #20
Senior Member
 
5picker's Avatar
 
Join Date: Aug 2015
Location: South Western PA
Posts: 2,916
Quote:
Originally Posted by jstaffon View Post
I knew what you meant...
I figured most would.
__________________

__________________
_________________________________________
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel
Ford F-Series SCREW 4x4
TST Tire Monitor - Sinemate 3500w Gen.
2016 Nights Camped = 46
5picker is offline   Reply With Quote
Reply

Tags
dometic, fridge

Thread Tools
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




» Virginia Campgrounds

Reviews provided by




ForestRiverForums.com is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 09:32 PM.