Cold air

[DoubleWideDrama]

We can feel very cold air coming out of the heat vents when the furnace is off, also we have an indoor cold-air return and can feel cold air there too. Our furnace is an outside unit that was installed in 2008 by the previous owner.

Is this normal? Does it mean we should re-insulate the ducts in the spring when we can get under there? Or is this part of living on a slab?

Thanks
Tara

[Robert]

Hi Tara,

Where is furnace located outside ? What is brand and model number ?

Clarify living on a slab ?


Can you take and send me pics to robert@mobilehomerepair.com ?


Thanks,
Robert

[DoubleWideDrama]

The furnace is located outside near our bedroom. I sent a picture to your email. We live on a cement slab with tie downs and skirting. I'm not sure if that's what you were asking???

The furnace is a Nordyne brand and I have NO idea what the serial number is. lol. Maybe it's an Intertherm... check out this website.

http://www.intertherm.net/

That's what our unit looks like. If you have other questions I'll try my best to answer them.

Thank you guys soooo much!
Tara

[Robert]

Hi Tara,

Will be back after I have some supper to give you the info you need to resolve this.


Thanks,
Robert

[Robert]

Hi Tara,

What you have is a packaged heat and cool unit where the a/c condenser, evap. coil, cond. fan, blower motor and heat source are all inside the one unit.

With what you described, I would guess your return and supply ducts from main home duct to the outside unit have been compromised and either come loose or have been torn open.

Inspect them from outside unit to home duct and ensure they are not kinked, loose or torn.

Using all metal duct wrapped with foil backed insulation is best for this. Flex duct will need more inspections and maintenance due to ease of tearing and kinking/collapsing.


Thanks,
Robert

[DoubleWideDrama]

So basically what you're saying is that some of our hot air is getting out of damaged ducts and into the area beneath our home? Then when the furnace is off, the cold air is getting in the damaged ducts and coming in?

If we find holes in the ducts, how do you patch them?

Is this what you're talking about? http://www.lowes.com/pd_179375-1410-SP5 ... 0$y=9$x=23

[Robert]

Hi,

Yes. You most likely have flex ducts and only way to repair if torn is to replace. If just loose at the connections, reconnect, secure with screws, foil tape, zip ties.


Best way to eliminate though is with all metal duct wrapped with what you showed from Lowe's.

Then wrap that with chicken wire IF rodents are a problem where you live.


Also, you can have a plenum box built to cover the pipe outside home from unit until it goes underneath.

An hvac company could do it and that protects the ducts from weather and animals.

Then seal good around skirting where it goes underneath home.


Thanks,
Robert

[DoubleWideDrama]

The more we dig in this project the more upset I become. We definetely got what we paid for.

We will have to wait until spring, get into the underbelly (which only seems to have 2" of really CRAPPY isulation in it) and revamp most of the underneath.

Thanks for your help. I'm sure I"ll be back.

Tara

[Robert]

Hi Tara,

The problem most likely lies in one or both of the two ducts running from outside unit under the home and connecting to a collar at the main home trunkline ducts.

Wouldn't need to enter the underbelly to repair that or replace with all metal ducting.


IF you change the insulation in underbelly, ensure it stays even, hangs down somewhat and is not compacted.

It is the way it is in order to allow even airflow throughout the underbelly from the transfer of heat from the the trunklines to ensure the waterlines do not freeze.

The main thing is to have a tightly sealed underbelly and also a completely sealed skirting with no holes and insulating back of skirting goes a long way in helping also.

IF the insulation is compacted, too thick or not allowing even airflow, you will have hot and cold spots that will create condensation and moisture which the insulation will absorb and then you have mildew and mold and rot problems.


Keep coming and asking here and in the mobile home repair forum and others and we'll help all we can.

Thanks,
Robert

[DoubleWideDrama]

We are currently at the stage where we ripped up the floor. We were planning on insulating between the 2x6s between the underbellly and the new floor (I think they might be called trusses?)... is this a good or bad idea? Initially I thought it was a great idea until you just said there needs to be space between the underbelly and the floor to allow air flow.

[Robert]

Hi Tara,

It can have its advantages and disadvantages. problem lies in how trunkline is ran and how the insulating is done.

IF done incorrectly or trunkline is not run exact, then it will backfire big time.

Trunkline would have to be ran below the floor joists and the insulation would have to remain in between the joists and not fall down.


IF you seal skirting and insulate back of it and seal underbelly and stuff some loose insulation into any holes beforehand, shouldn't have any problems.

IF your underbelly is in bad shape and tru nklines exposed, good time to seal any openings with foil tape and mastic duct sealant. Do not get the mastic on your hands for prolonged periods.


Thanks,
Robert

[DoubleWideDrama]

Forgive me for not knowing but what is the trunkline again?

[Robert]

The two main ducts running down length of home, one in the center of each half of the doublewide.



Thanks,
Robert

[DoubleWideDrama]

Ok, thank you!!! I should probably already know some of this stuff but I just can't remember everything!!!


Tara

[Robert]

Hi Tara,

You're very welcome, happy to help.



Thanks,
Robert