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Author Topic: Older furnaces output temp issues?  (Read 279 times)

PancakeBill

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  • Bill & Jolene/USA 97 Southwind 35P
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Older furnaces output temp issues?
« on: November 21, 2017, 07:40:45 PM »
Our 1997 Fleetwood Southwind has 2 furnaces, the front is 35k but.  Rear is a 20k but.  Both Atwood 8900 lll.  We had it in at Lazy Days today, the tech tells me the rear is performing properly, DW feels that it is not producing enough heat.  I checked with a thermometer made for purpose, right about 120 deg.  Is this correct? 

I had to replace the relay for the front furnace and their rules say they can't work on anything modified.  Sure it isn't the original, but it is the same function.  Anyway, that one I am ready to just replace, right now it won't stay lit, you can hear it try, but doesn't stay lit.  Sounds like the flame is missing the sensor, or sensor bad, but I can't seem to get at it.  The new Atwood 8500 lV is supposed to be the replacement, but some dimensions concern me, although the specs make me like it a lot. 

Anyone ever do this swap?
Bill & Jolene W & Koda

Old Faithful, Yellowstone Association Bookstore
1997 Southwind 35P
Toads: 1997 Honda Accord & 1986 Westfalia
FMCA F-401354
1995 OMI Dobro F-60
WA1RI

DearMissMermaid

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Re: Older furnaces output temp issues?
« Reply #1 on: November 22, 2017, 06:40:05 AM »
Lots of heat options to consider, my favorite being I have a mattress warmer so that no matter what, I sleep warm and toasty.

When I needed a new overhead AC, I put in a heat pump. So now I have both electric (overhead) and propane (basement) heat.

Most all overhead AC units also have the capacity to install a heat strip which will pump out 1500 watts of electric heat. Typically the part is under $100.

The newfangled ceramic heaters, especially the slender rotating towers can put out amazing amount of heat for minimal cost.

https://www.amazon.com/s/ref=as_li_ss_tl?url=search-alias=aps&field-keywords=ceramic+tower+heater&sprefix=ceramic+tower+,aps,165&crid=3MVWY342BH69Y&linkCode=ll2&tag=recreationalvehicles-20&linkId=31a36bcdbe5c68f387c8d1d95895f715
http://DearMissMermaid.Com

Living, working. playing  in a 1992 Holiday Rambler Imperial 36' 5th Estate, formerly 8 years 24/7 in a Class C, 1994 Tioga Montara, 28'

Pack half the stuff and twice the cash.
http://dearmissmermaid.blogspot.com/

John From Detroit

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Re: Older furnaces output temp issues?
« Reply #2 on: November 22, 2017, 07:04:40 AM »
The correct outlet termp is a complex calculation 120 sounds.. Reasonable.

Factors include Burner size (BTU's produced), Inlet temp, THe Cubit Feet of air the blower blows every unit time (CFM) and how far from the furnace you are measuring.. But 120 is actually warm enough that if you stepped on a floor register barefoot.. You would very quickly move your foot. Some folks might even blister. This is why Water Heaters are normally limited to 120  Do not want to burn you.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

Old_Crow

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Re: Older furnaces output temp issues?
« Reply #3 on: November 23, 2017, 07:03:39 AM »
I went the other direction.  I replaced an 8500-IV with a used 8500-III(8500 and 8900 are very similar, hook up wise).  It was all I could find at Colaw at the time.
I had to swap the plenum chamber on the back of the unit because of the cutouts for the vents, but that was the only difference installation wise between the 2 units.

You'll like the -IV unit, because they are way more quiet than the -III.  If I ever win the lottery, I'm buying a new -IV to replace that noisy old -III.
Wally Crow
Retired 30 year ASE Master Auto Tech
Y2K Bounder 36S F53
'03 Jeep Wrangler Sahara

PancakeBill

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Re: Older furnaces output temp issues?
« Reply #4 on: November 25, 2017, 08:01:24 PM »
Thanks all,  the 120 I finally found some specs and the range is 120-130, so in range.  The 8535 lV sounds like what I want, my only concern is I think I will need to fill a gap.  The width is the same but height is slightly shorter. 

I am awaiting word there will be one for me on Monday.  Hoping to get it in and installed before we start heading north. 

If we can't, we will just tough it out and hit hotel if necessary.

Hoping hooking up will be the same, but I can handle it is not.

Bill & Jolene W & Koda

Old Faithful, Yellowstone Association Bookstore
1997 Southwind 35P
Toads: 1997 Honda Accord & 1986 Westfalia
FMCA F-401354
1995 OMI Dobro F-60
WA1RI

 

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