Question about insulation around furnace

[DP]

I have a double wide with a Coleman EvCon model #DGAA070BDTA. I can feel heat coming in around the edges of the unit.

Let me explain it's layout.

The home has cathedral ceilings except over the master bedroom's closet and bathroom and utility room/wash room (which the furnace is in). This is one end of one section of the the home. Where the unit is mounted in the wall, behind it is the closet for the master bedroom. Beside it is the water heater (accessed through the Master bedroom's closet). The closet is always hot with no air vents.

Here is a basic diagram of how it's layed out:


The walled areas around the furnace/AC are always hot (the cabinets, closet, water heater, etc.

My question is would it be ok to insulate around the two sides of the furnace? I know not to insulate around the top without special insulation, but what about along the sides of the case where it mounts in the wall?

[tnt17]

wow, looking forward to some great replies on this..your layout/diagram is almost exactly as mine. Just add a 4th bedroom in between bath and br on the left and utility room after that.
out of curiousity, how big is your return air grill on the furnace? or if you can take a picture and post, even better.

[DP]

Here's a pic of the furnace with it's cover (air intake). Where I'm wondering about putting insulation is along the crevices on the sides of the case (you can see the gaps).

[tnt17]

Looks close to mine. I'd imagine the foam expand stuff would be just fine as well...let it get hard then trim the excess with a sharp cutter.
I also added another return (cut into the wall just to the adjoining wall side) as i heard 'the more air the better to return'.

[Robert]

Hi,

Every furnace has set space dimensions required around it. Look at your manual to see what they are for yours.

IF you can place something there, it would need to be fire rated.


Every furnace-a/c system has a set amount of cfm airflow required for that unit.

You cannot go under or over. More air for return is never better
except in cases where you have too little.

Increasing airflow can/will damage your system IF you go over.


Your louvered doors are designed for your furnace and the set size of a/c your furnace can handle.


If you feel surrounding walls are too hot, have a Tech inspect and service/clean furnace.


Be sure filter is clean and is not obstructing airflow by being a non-recommended filter.


Thanks,
Robert

[DP]

Robert, this is a complete coleman unit. The grills shown pop off the front and the whole unit is in a case (about the dimensions of the grills). The gaps along either side are outside the furnace case. What I'm asking is could these air gaps be filled with insulation and then a small trim piece be added to the front to cover these gaps or should I just leave the air gaps and add the trim? Here is a pic with the grills removed:

[DP]

BTW Robert, we have just moved into this trailer and have no manual for the furnace. Does coleman or someone else make the Owner's Manuals for this furnace available online?

[tnt17]

Yours isn't on this link is it?

http://www.dgatprogram.com/index.asp

[DP]

Yours isn't on this link is it?

http://www.dgatprogram.com/index.asp

No, mine is a DGAA model. I found a technical guide at http://www.acdirect.com/xcart/images/pr ... rnaces.pdf, but have been unable to find a owners manual that covers operation, etc.

In the technical guide it does list under features: "ZERO CLEARANCE FEATURE allows these furnaces to be installed where space is a premium."

I'm wanting to block off any warm air making it's way around the edges of this case and into the air intake. My thermostat is mounted on the wall just to the side of the unit (you can barely make out it's side profile in the above pictures). It is a programmable thermostat that also has humidity features that will run the A/C if a humidity threshold is crossed. I have seen this humidity level over 80% after the A/C has been running for hours. I believe that it's mounting location, and the warm air making it's way beside the furnace case, has a lot to do with this.

[DP]

I just had an A/C tech install a new outdoor unit and inside A-coil that the previous owner provided in the sale. This weekend I got under the trailer and replaced the flex that was water saturated and laying on the ground snaking around (too long) connecting the two trailer halves.

I noticed my humidity level get to 94% a little while ago so I removed my thermostat and set it in the family room against the wall at the level it sits at when mounted and it dropped to 60%.

I took the wall cover off above the furnace and this is what I found. What are my options here for sealing this up?

[DP]

This is my solution. Please let me know if I'm doing something wrong or endagering myself.



The attic has blown-in insulation, but is missing a little above and to the sides of the hole which I filled in with the insulation alone from duct flex (in between a couple joist you can see in previous pictures that had none). I broke the old ceiling back around the hole so that I could get to the vapor barrier at parts it wasn't sticking out. I then used the foil backing from flex duct and alum. A/C tape to seal the outer exhaust stack to the vapor barrier. I then went back over it with that same tape to the old ceiling to provide extra support.

It's a while until I'll need the heat here in Savannah (very hot and humid here), so if I need to change something, I have plenty of time. I just want to make sure it's done right and will not pose a safety risk.

As for the original question, instead of insulating along the sides I plan on just using the A/C tape to seal the sides of the case to the surrounding drywall. I'll then install trim to cover it where the gap is shown above. This should stop warm air inside the wall from being pulled around and into the air intake.

[Robert]

Hi,


I understand how the door panels and units work and fit into wall casement, this makes 29 years in HVAC service field.

By dimensions, I meant the gap around unit.


Some units require a certain gap, others don't.


IF the walls and such are hot as you stated, sealing gap will make them hotter.

At the top should be repaired with fire retardant board and a ceiling ring around roofjack to seperate pipe from board.

Then tape around ring with foil tape.


The roofjack can seperate and expose hot vent piping, so you don't want anything not designed for that to be around it that can burn.


Since you just moved in, a service/clean/inspection by a Tech would be wise.


Thermostat should be moved, not best location.


Will give furnace manual's we sell link in a few.


Mark(owner of site) handles that and is away until end of week.


An inspection will answer all questions and find any safety flaws in system due to malfunction or poor maintenance.



Thanks,
Robert

[DP]

Thank you Robert. I will have a tech come look at it and see what they recommend doing.

[Robert]

Hi,

You're very welcome , happy to help.


Here is the link to purchase a furnace manual if we have it:

http://www.hvacmanuals.com/



Take care and best wishes,
Robert