COACH FURNACE RECREATION? CAN A LESS POWER HUNGRY FAN BE USED?

S

slc

New member
Jan 24, 2017
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UGH! ! This is a second attempt at posting. The first one disappeared.
Apologies if you get two postings...

The Coach Furnace is a power pig. if you are booning and you turn the furnace on to heat overnight, you will most likely wake to a cold coach and
dead battery.
It is the nature of the beast and the RV market has lived with this problem up to this very day. There has been no improvement.

To counter this RV owners, especially those that boon with no outside power source, have turned to unvented propane heaters, catalytic and blue
flame.
Granted, these all work well, they make the interior toasty warm but can use up the oxygen and infiltrate your interior breathable air with carbon
monoxide.

I am one of those, I have a buddy heater and it puts out a good heat for its size. I liked it a lot, up until the day it made a funny noise and
bursted into
flames.
My heater had an internal fitting fail and it just started to leak propane gas while it was running.
I did post comments about this and I STRONGLY RECOMMEND that you only use this type of heater when you are there to monitor it and not run it when you
are sleeping or away from the coach. It is potentially dangerous.

https://www.youtube.com/watch?v=noAHa0LfNcY

https://www.youtube.com/watch?v=hh11VPUoKXI

https://www.youtube.com/watch?v=c5PA3oP6yJg

So back to the coach furnace. Has anyone attempted to replace the power hungry fans with a lower powered fan, like a computer type muffin fan? Is
it possible?

If it has not been done yet, there must be a reason, hopefully OTHER than making money, as to why the industry has not attempted to remedy this
problem.

Thanks for reading
--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
Have you checked new furnaces? I'd imagine the newer furnaces are very fuel
efficient. I use a small room heater in my RV and it's never failed me or
killed the house batteries. It also has a quiet built in fan. Disclaimer I
can sleep in a rock concert so what I call quiet might not be yours. :)

Sammy Williams
 
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
 
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 <

> 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
http://www.appliedgmc.com
1-800-752-7502
 
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 <

> 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 <

>
> > 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
> 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
>
 
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
 
I've a Suburban the PO installed not long before I got the coach. The battery holds it up overnight without any problems at the two venues I used to
visit which required dry camping.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
 
Not my experience. The new Suburbans are identical to the old, and probably
no better than 80% efficient.

Mine is anything but silent, but it’s no noisier that my CPAP machine (or
my previous snoring).

How much of a hit it makes on the battery depends on how much the furnace
has to run to keep it tolerable in the coach. GMCs were never optimized for
really cold weather. For temps down into the 30’s, I can run my furnace all
night with no worries. With temps in the teens, it might have to run
continuously to satisfy the thermostat. I don’t know where that line is. If
I wanted to use my coach in weather that cold, I’d start with insulation,
including insulated covers for the windows.

Rick “who installed a new suburban in the case of an old Suburban without
modification” Denney

On Sun, Feb 10, 2019 at 2:31 PM Sammy Williams via Gmclist <

> Have you checked new furnaces? I'd imagine the newer furnaces are very fuel
> efficient. I use a small room heater in my RV and it's never failed me or
> killed the house batteries. It also has a quiet built in fan. Disclaimer I
> can sleep in a rock concert so what I call quiet might not be yours. :)
>
> Sammy Williams
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
 
I'd check to see if your motor bearings need oiling and if your house battery is losing capacity with age. I'm sure there is something out there like
a digital brushless motor but that would require some research for proper RPM and sizing.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I just replaced my Sol Aire heater with an Attwood 8531-LD hydroflame 30,000 btu size. The book says it uses 7.8 amps. I selected this furnace because:
(1) similar size to the old furnace, allowing me to use alot of the existing ductwork.
(2) Higher efficiency
(3) Uses a single 3 1/2" hole for both the combustion air inlet and exhaust

As our friendly Jim has in his coach, two 6V deep cycle batteries in ours. It runs about four or five nights without a battery charge. For us, dry camping is something we might do over a long weekend, but no longer, so the run time is just fine for us.
 
Last edited by a moderator:
on the discussion about RV heating...has anyone ditched the furnace for a
propane radiant heater?

--

William D. Weyrowski
Midland, MI and Surfside, FL
73 - 26' Sequoia
 
Radiant heaters have pros and cons. The pro- is they are pretty silent, do not use much in propane, and they do not use any 12v power. Great
for boondocking.

However the cons: You have to be really careful about venting and fresh air, they usually have safety devices, but they can use up oxygen. They
are also a little more of a fire hazzard. Lastly, not a safety issue, but they do can be a real moisture problem, and usually they do not have the
BTU capacity of a furnace, so depending on the temps you are dealing with, and the insulation in the coach, they may not keep the coach warm.

I have both, and depends on situation how I use either a furnace, or a big buddy radiant heater.

--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
> on the discussion about RV heating...has anyone ditched the furnace for a
> propane radiant heater?
>
> --
>
> William D. Weyrowski
> Midland, MI and Surfside, FL
> 73 - 26' Sequoia
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--- ---

The coach furnace is ideal for campground camping when connected to land power. They also are pretty fair if you have a good sized solar system and
battery storage. The single battery that comes OEM is not enough and the coach furnace will run the power out of it. When the power is gone, the
furnace shuts down and it gets cold.

As illustrated in the vids and my own experience, the BUDDY type heaters are fragile and can break some of the interior aluminum connections. When
this happens, the heater can flame up at anytime, IT WILL BURN YOUR COACH DOWN! ! !
This happens if the heater has been put through stress, like being dropped or tipped over hard, thrown and dropped, etc. If this happens even once,
you may have a heater that can fault and flame up. When mine caught fire, all I heard was a funny pressure loss sound, the flame started inside the
heater, caught the foam insulation on fire and then started the outside plastic body on fire. If I were not there, I would have lost the coach.

This is not something to be looked at lightly as this is now a serious concern if you drop or bang the heater even ONE TIME...

On the positive side, as said before, they use less propane because you are not letting heat escape through the exhust system, and they don't use any
12v power, well most don't .

Do you keep the furnace????
Yes and No.
Yes if you plan to use it when in a campground on land power.
If you plan to carry electric heaters, you can plug them in but be aware, electric heaters do not match the output of the furnace in heat measurement.
In a really cold environment, the electric heater will leave you cold because it cannnot keep up with the cold temps. As long as the furnace does
not have a power loss, it will keep the coach warm.

When booning, the ventless heaters are also smaller than the furnace but you don't have a lot of choice, even if you run the generator, you will
eventually run out of fuel for the gen set.

You have to think your heating alternatives out very well and make good decisions.

--
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
UBUNTU VOYAGER - Berzin Auto Center
 
I find that as long as you take care of your batter system it will support
the furnace.
Most of us use two 6 volt Deep cycle Golf cart battery, hooked in series.
I have seen so many use this combination for many years.

On Wed, Feb 13, 2019 at 5:23 PM slc via Gmclist
wrote:

> > on the discussion about RV heating...has anyone ditched the furnace for a
> > propane radiant heater?
> >
> > --
> >
> > William D. Weyrowski
> > Midland, MI and Surfside, FL
> > 73 - 26' Sequoia
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> --- ---
>
> The coach furnace is ideal for campground camping when connected to land
> power. They also are pretty fair if you have a good sized solar system and
> battery storage. The single battery that comes OEM is not enough and the
> coach furnace will run the power out of it. When the power is gone, the
> furnace shuts down and it gets cold.
>
> As illustrated in the vids and my own experience, the BUDDY type heaters
> are fragile and can break some of the interior aluminum connections. When
> this happens, the heater can flame up at anytime, IT WILL BURN YOUR COACH
> DOWN! ! !
> This happens if the heater has been put through stress, like being dropped
> or tipped over hard, thrown and dropped, etc. If this happens even once,
> you may have a heater that can fault and flame up. When mine caught fire,
> all I heard was a funny pressure loss sound, the flame started inside the
> heater, caught the foam insulation on fire and then started the outside
> plastic body on fire. If I were not there, I would have lost the coach.
>
> This is not something to be looked at lightly as this is now a serious
> concern if you drop or bang the heater even ONE TIME...
>
> On the positive side, as said before, they use less propane because you
> are not letting heat escape through the exhust system, and they don't use
> any
> 12v power, well most don't .
>
> Do you keep the furnace????
> Yes and No.
> Yes if you plan to use it when in a campground on land power.
> If you plan to carry electric heaters, you can plug them in but be aware,
> electric heaters do not match the output of the furnace in heat measurement.
> In a really cold environment, the electric heater will leave you cold
> because it cannnot keep up with the cold temps. As long as the furnace
> does
> not have a power loss, it will keep the coach warm.
>
> When booning, the ventless heaters are also smaller than the furnace but
> you don't have a lot of choice, even if you run the generator, you will
> eventually run out of fuel for the gen set.
>
> You have to think your heating alternatives out very well and make good
> decisions.
>
> --
> GatsbysCruise. \
> 74GMC260 Former Glacier Model style. \
> Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS
> FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO -
> UBUNTU VOYAGER - Berzin Auto Center
>
> _______________________________________________
> 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
http://www.appliedgmc.com
1-800-752-7502
 
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