| [GMCnet] COACH FURNACE RECREATION? CAN A LESS POWER HUNGRY FAN BE USED? [message #340859] |
Sun, 10 February 2019 14:26  |
JerryW
Messages: 256
Registered: August 2018
Karma: 1
|
Senior Member |
|
|
I have not researched this issue myself but since the fan powers the burner as well as pushing air across the heat exchanger I would guess the manufacturer has fitted the lowest power draw blower they think would meet both demands in the wide variety of applications where these furnaces are used.
If too little air is supplied to the burner then the furnace will not fire or will burn too rich. If too little air passes over the heat exchanger then the high temp limit switch will open and the furnace will not run.
Meter yours while in use and you will likely find it draws 7 to 9 amps while running. If that is the only power draw then it would take a fully charged 140 to 180 amp hour battery bank to power it for 10 hours.
Best way to keep the air flow where it belongs with the stock fan is to keep the squirrel cage clean and shaft lubed and to use a shorter run of larger wire to supply 12vdc to the furnace and a larger, shorter run to provide good ground. Depending on the upfitter and year the stock wiring may have been marginal from the get go.
Jerry Work
Kerby, OR
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
|
|
| Re: [GMCnet] COACH FURNACE RECREATION? CAN A LESS POWER HUNGRY FAN BE USED? [message #340865 is a reply to message #340863] |
Sun, 10 February 2019 16:26  |
JerryW
Messages: 256
Registered: August 2018
Karma: 1
|
Senior Member |
|
|
8 or 10 amps draw is a lot to ask from a 12 volt battery on a continuous
basis. Even 10 minutes out of 60 is quite a bit. Makes more sense to use
stored fuel to heat the interior of a coach. That, combined with
improvements in heat loss like insulated window coverings and more spray
foam wherever you can put it will help a lot. There might be air handling
fans that draw less than what I have described here, but I haven't seen
them. But, for everyone who says "That can't be done, there is someone who
picks up the challenge and finds a solution".
Jim Hupy
Salem, Or
On Sun, Feb 10, 2019, 1:54 PM Jim Kanomata via Gmclist <
gmclist@list.gmcnet.org wrote:
> I make sure that the batteries are fully charged by 8:00 pm and keep the
> temp set at 67 degrees so it will not kick on frequently.
> Also turn off all unnecessary electrical.
> I have found that one can run the coach engine to charge the coach battery.
> The new furnace still use lot of power. Muffin fans cannot draw enough air
> and the burner will overheat and burn through the burner or the unit will
> shut down.
>
> On Sun, Feb 10, 2019 at 12:27 PM Gerald Work via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> I have not researched this issue myself but since the fan powers the
>> burner as well as pushing air across the heat exchanger I would guess the
>> manufacturer has fitted the lowest power draw blower they think would
> meet
>> both demands in the wide variety of applications where these furnaces are
>> used.
>>
>> If too little air is supplied to the burner then the furnace will not
> fire
>> or will burn too rich. If too little air passes over the heat exchanger
>> then the high temp limit switch will open and the furnace will not run.
>>
>> Meter yours while in use and you will likely find it draws 7 to 9 amps
>> while running. If that is the only power draw then it would take a fully
>> charged 140 to 180 amp hour battery bank to power it for 10 hours.
>>
>> Best way to keep the air flow where it belongs with the stock fan is to
>> keep the squirrel cage clean and shaft lubed and to use a shorter run of
>> larger wire to supply 12vdc to the furnace and a larger, shorter run to
>> provide good ground. Depending on the upfitter and year the stock wiring
>> may have been marginal from the get go.
>>
>> Jerry Work
>> Kerby, OR
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] COACH FURNACE RECREATION? CAN A LESS POWER HUNGRY FAN BE USED? [message #340876 is a reply to message #340859] |
Sun, 10 February 2019 19:45 |
 |
RF_Burns
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
|
Senior Member |
|
|
I noticed the first time I needed the furnace that there was very little air flow out the 4 floor vents. Each vent has its own duct hose which I checked for blockages. The duct hoses come off the side of the furnace and are ribbed with a spiral spring (not smooth). I suspect the turbulent air and the ribbed duct work was resisting the air flow.
One extremely cold morning the pressure was on to get the coach warmed up! So I opened the bottom access door and removed the front cover of the furnace. The volume of hot air coming out the open front of the furnace was almost overwhelming! The coach quickly warmed up To this day the front cover remains off. I just unlatch the door before turning ON the furnace. The volume of air blows the access door open if it is closed but unlatched.
I'd say the furnace now runs about 1/4 of the time previously required.
I've talked to one of my Clients in the sheet metal business about fabricating a smooth metal duct. Its on my todo someday list.
Just my experience.
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
