Furnace floor R&R ?

Post all other heating and cooling questions here.

Moderators: Greg, Mark

jeff

Hello, I was searching the net and found you folks.

I hope there are experienced furnace installers here.

I bought a low milage, three year old, miller down draft oil mobile home furnace. After removing the old furnace I see the floor is badly rotted, from the washing machine leaking.

My question is. When installing the new floor, how much clearance, if any, between the wood, and the "boot" inside the furnace base that directs the warm air from the furnace, to the duct?
User avatar
Yanita
Moderator
Posts: 3369
Joined: Sat Feb 17, 2007 10:16 pm
Location: Eastern N. Carolina

Hi Jeff and Welcome to the site...

I am going to move this thread to the HVAC forums, please follow it there.


Yanita
Last edited by Yanita on Mon Nov 05, 2007 6:42 am, edited 1 time in total.
The difference between success and failure is who gives up first!
User avatar
hvac1000
Posts: 292
Joined: Wed Feb 28, 2007 9:19 am
Location: Cincinnati ohio

There should be a metal/paper tag on the unit that will state clearance to combustibles. It will list the sides back and front and the top and bottom.
God, grant me the serenity
to accept the things I cannot change;
the courage to change the things I can;
and the wisdom to know the difference.
jeff

I felt dumb after not looking there, (used to that old rusty junker with no stickers). I looked and it dose not give the floor opening clearance.

I did see the base it requires, it's cb-200a. I searched the net with that and nordyne and came up with

"Cut the opening for the feeder duct 14-1/8" x 14-
1/8" in flooring (cutting opening 1" larger all the
way will allow the flanges on the underside of the
base pan to fit in the opening)."

I am using the base from the old furnace, and the the "flanges on the underside of the
base ", are the same measurements as noted above.

The throat opening from furnace to duct is 9'x12', thus allowing 1' on 3 sides, and 4+" in front.

So that is what I am going with.

If anyone has comments, please speak up.

And if anyone needs a part from the removed "antique" 1972 miller gun speak up quick as I will soon take great pleasure in kicking it off the back of the truck at the scrap yard.

Thanks, Jeff
jeff

Another question for you furnace guys.

Those transformers from the 70s miller oil furnaces, Is it safe for me to tear those apart for the copper, is there toxic materiel in there?

I have several, and they are not usable on the newer furnace.
jeff

What a job. I do not envy trailer furnace guys one bit.
Tore out old floors and reinforced then three layers of plywood.
Cut out the throat, fit base and screwed it in every corner.
Installed furnace on base and screwed it to base in all corners.
Climbed under the trailer (trolls and spiders live under there) and fed up the fuel line.
Next it's the easy part of wiring and connect fuel line.

I got mad and sawed off the stack pipe because I couldn't get it apart.

Question is. What is the easiest way to remedy that mistake? Do I need a new roof jack or another way? I see someone here sells this stuff, help me out?
Top of furnace cabinet, to ceiling is 22 1/2 inches, about 8" through roof and whatever I need standing above. The existing stack is ruined from 12" above cabinet, down to cabinet.

Nordyne Miller, CMF down flow, 75,000 BTU,
RWB Becket Model AF-15 gun
Exhaust port is 4".
jeff

I just ordered a new jack from a local furnace guy. Will be here in one day. Thanks.
User avatar
Robert
Moderator
Posts: 6413
Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

Hi,

Sorry, was away from pc and very busy over last 4-5 days and just now seeing this.


Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
jeff

No problem, busy time of year for you guys I'm sure. Picked up the jack today and soon as I can get this little gran daughter bedded down I'm going for it.

While I have your ear, I have other thoughts. :D

1 In the area of the burner, with new floor installed, there is no vent or air intake. I mean, it's enclosed area when door is closed.
Is this okay? Should I caulk around the incoming single fuel line?

2 I plan to vent the top area, fan area, like the old furnace was. But the newer unit appears it was not vented there.

3 Will the old 1972 thermostat be ok with the 05 furnace that likely had digital?

I'm sure I will have other thoughts. Anticipating the first burn.

I do plan to read all the paper work, again.
User avatar
hvac1000
Posts: 292
Joined: Wed Feb 28, 2007 9:19 am
Location: Cincinnati ohio

Follow the directions for the new furnace and do not deviate.
Do not enclose any furnace without combustion air.
God, grant me the serenity
to accept the things I cannot change;
the courage to change the things I can;
and the wisdom to know the difference.
jeff

Old jack is in the yard, new one is installed, rain drops made me hurry at the end. I used the old furnace door as the new ceiling escutcheon.

I read all paper work and stickers on the unit they say nothing about combustion air.

On Nordynes website it says 7"x2".
This should have been cut out before base installation and laid out before the sister and extra joists were installed, Grrrrr.

There is no "combustion duct" under this home. I'm thinking I am going to find a way to get 14 square inches of opening from combustion area to under the home.

I could not template or copy from the old as there was no floor there (rot).

Comments are most welcome.
User avatar
Robert
Moderator
Posts: 6413
Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

Hi,


Yes, the combustion air comes in through an approx. 7" opening in bottom from underneath home.


When you say you used old door as an escutcheon, did you get a new Nordyne roof-jack ?

If so, it should have come with flashing/base and nothing else needed.


Thanks,
Robert
Some people are Humbly Grateful, while some are Grumbly Hateful.................... Which one are you ?
jeff

Yes, brand new jack with barrel approved for this unit, it came from Quinn. The original was get this, Double wall like the ones approved for gas only. Only bad thing is the roof flashing is smaller than original, thus not covering the screw holes of the old.
No big deal though, roofers fabric and roof cement cures that. I learned that some jacks allow combustion air feed from the outer wall of the jack, this one is not like that.

I used the door for interior escutcheon at ceiling. The original was 1x4 box and a piece of paneling, that could easily have fallen down onto the furnace.

A two peice escutcheon collar came with jack, I assume it goes on the interior. If I am wrong, please advise.

Combustion air is now going to come from attic area via 2, 3" ducts allowing 7.065 square inches each, with mouse proof ends.

This set up has been heavily scrutinized by a local trusted furnace guy, and Tech named Doug at Nordyne was of great help.

Though I have had most every mechanical part off of the old unit in the last 18 years, and trouble shot others, this is my first total oil furnace R&R, and I learned a lot.

Considering furthering my education as there seems to be a niche market in mobile home furnaces as the older techs shy away from oil mobiles.

I have 452 bucks into this so far, only other things I need (so far) are a new nozzle and a fuel filter. First burn should be soon.

Speaking of nozzles. Do you guys have an online chart for what nozzles are recomended for different units?

Thank you Yanita, hvac1000, and Robert for replying, I know it is touchy replying to these when you can not see what I'm working with, jeff
jeff

Thermostat question

The old furnace had two screws at reset switch area for the thermostat. White wire went to screw labeled T1, red to T2.

New furnace has two screws. One labeled E1, the other not labeled.

What wire goes where? Dose it matter?


Edit, thermostat is 1972 model old style with two wires and controls the furnace only.

Edit again. stat stats,
White-Rodgers
max voltage 30 ac
.15 to 1 amps
E1 type 1030=324
jeff

[/b]HOUSTON, WE HAVE IGNITION
Locked
  • Similar Topics
    Replies
    Views
    Last post