Furnance Vent Return Under Steps

[Clemson1881]

Just got back from Disney's Fort Wilderness. Before we left I decided to try the closing off the furnance returns under the steps to aid the air conditioners. It has been posted before this really helps, so I did it. I wanted to report the difference is amazing. 90 degree plus weather with 80% plus humidity posed no problems even in the middle of the day with the sun beating down on the rig. I ran the front unit on low and the back unit on auto fan. Both are ducted. The back unit cycled off often, and never got above the low fan speed on auto. Temp inside maintained at 74 degrees and humidity measured around 33% inside with it at 80% outside. I was very pleased. Now to try it at Myrtle Beach in a couple of weeks parked right on the Ocean.

[wingerphil]

Greg, what type of material did you use to block it off?

[The Old Fogies]

I'm interested also. Headed to the State Park in Myrtle Beach the weed after the 4th. Could you post what you did?

[1retired06]

Sounds like a smart idea for us to try.

[dieselguy]

I'm just adding to the discovery of what is or isn't behind the grill below the steps. Here's an old post of mine ... after adding the insulation I don't really need to block off the grill anymore as the cold air doesn't flow into the storage compartment (cargo doors don't seal 100%) or on down into the belly pan and onto the ground anymore. I was amazed at the difference it made both summer and winter!! http://www.montanaowners.com/forums/...ad.php?t=44580

[swanny]

Yes this works great, I started doing this about five years ago. I was getting stuff out of my basement and it was very cool in there so i sealed off the return. I used the stuff you put on the inside of a windshield. Also don't forget to do your registers in the floor, they also send air back to to the underbelly. And while your at it you might as well seal off all the larger holes under the cabinets. We also used the same silver bubble material to cover to inside of the windows on the sunny side of the monty. Bought a roll at Lowe's and cut it to fit attached with velcro.

kevin

[Art-n-Marge]

I imagine this is a great idea! The biggest concern is that the vent covering needs to be very obvious and easy to remove so that I remember to remove the thing when I start running the furnace. However that cover would sure prevent the coldest air from exiting the rig and improving the efficiency of the A/C.

[Clemson1881]

I removed the wooden grills, attached a piece of cardboard on the backside with insulation on the backside of the cardboard, and used velcro to re-install the grills to the steps. That way it is easy to pull them and remove the covers to operate the furnance. I also thought about the heat registers, but I got such great results from blocking the step returns I don't think blocking them off is necessary. I'm telling you this makes a huge difference!

[PackerFan]

I am getting ready to do this mod to our 3100RL. Sounds like you guys are getting good results and it works well. Thanks for adding to my work load.

[01RAMer]

Has anyone with a 3400RL tried this? I would like to know if it works for ours also.

[dieselguy]

If you have a 3150 and are contemplating blocking off the grill under the steps ... you might as well block of the grill under the fridge ... it's way bigger than the grill under the steps and connects to the same air pocket. 4 screws hold it in place.

[bighornram]

This is an interesting post. Recently I was under the steps on my 3400RL as I considered putting my EMS under there. I was quite shocked at how open it is to the storage area. There is a vent line running from the heater right into a hole in the floor. Goes nowhere, just blows into the underbelly. I'm hoping this isn't just a loose piece of duct material. The one to the bathroom floor came off and I had to ziptie around it for it to stay on the plastic vent. The space under the steps is completely open to the storage area with a simple panel screwed on. The whole top section has a 5 or six inch gap.

[Rob Walters]

Holy crap! I blocked off the vents under the steps today to see if my A/C would be more efficient......100 degrees out in the Texas Heat.....71 degrees inside. Yesterday it was even hotter outside and the temp inside prior to the modification was 86 degrees. My A/C is actually cycling off. Thanks guys.

[wingerphil]

quote:Has anyone with a 3400RL tried this? I would like to know if it works for ours also

Did ours this morning using cardboard wrapped in a plastic trash bag, not sexy but was the only materials I had handy at the moment.

This afternoon had record temps of 105 degrees and had both a/c's running. The inside kept a steady temperature at a comfy 73 degrees. All I can say is WOW! This mod is great.

Phil

[CORattler]

A good thought. Important to unblock before using the furnace tho. Any idea if there would be an impact to the refrigerator by blocking the vent beneath?

quote:Originally posted by dieselguy

If you have a 3150 and are contemplating blocking off the grill under the steps ... you might as well block of the grill under the fridge ... it's way bigger than the grill under the steps and connects to the same air pocket. 4 screws hold it in place.

[dieselguy]

Jay, I doubt if the decorative vent below the fridge on a 3150 has anything to do with the fridge operation. They had to install the fridge high enough to clear the furnace so the wooden grill fills in the gap. The air exchange on the fridge coils all takes place behind the fridge thats why there are two vents on your sidewall. If you remove both grills you'll find they both cover the same void underneath the steps continuing on to underneath the fridge. See my reply earlier in this thread about filling in the storage compartment wall and also just above the aluminum frame next to the upper floor. If you are inclined to folow my instructions for a 3150 anyways ... you'll not have to cover and uncover the grills depending on the season. My insulation mod fills in the big gap on the storage compartment wall that causes our fivers to leak air sooooooooooooooo bad.

[1retired06]

The heater feed going nowhere in the belly is intentional. That is Keystone's way of saying the underbelly is heated.

[bighornram]

quote:Originally posted by 1retired06

The heater feed going nowhere in the belly is intentional. That is Keystone's way of saying the underbelly is heated.

Thanks Mike for the confirmation. I thought that was probably the case but reaching into the hole and not being able to see what was down there.

[1retired06]

Just a thought, wonder if blocking those vents has any impact on the converting cooling properly? Our converter is located about 18 inches away from those stair vents.