[GMCnet] Anyone with experience on the Coleman Mach 8 AC/Heat pump ?

[Espen Heitmann]

I am thinking of replacing my original roof AC with a new unit that has a heat pump due to the Norwegian climate.

After some research I did find the Coleman mach 8 with the heat pump and the option for a heat strip wich you can not get on the duo therm in combination with a heat pump.

So has anyone any experience with the Coleman ?
--
1973 26' Parrot green Seqouia in Norway
"Loffen" translates to white bread, it is also a nick name for your.. well you know..down there.. and it was my dog's name, but hey you can also call me Espen ;)
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[Rob Mueller]

Espen,

I don't have any experience with heat pumps but there is one thing that no one has mentioned regarding the heat strips or heat pump
and that is that the hot air is supplied at ceiling level vs. the furnace which puts it out at floor level.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

[Espen Heitmann]

True Rob

And the hot air do rise, but you will get some cirkulation with the heat pump, however so do I think the largest drawback with an RV heat pump VS one for your home is that it does not recirculate the air.

But an RV heat pump with a heat strip must be better than one without, or ?



Robert Mueller wrote on Thu, 24 October 2013 16:20

[Rob Mueller]

Espen,

A heat pump with a heat strip would definitely put out more heat, however, you need to look at the amp draw with both running. I'll
be willing to bet that with both on you'll be real close to 20 amps if not over. According to Dou-Therm their 1500 watt heat strip
draws 12.7 amps. I'd be surprised if the heat pump would draw less than 7.3 amps especially on compressor start up.

Regards,
Rob M.
The Pedantic Mechanic

-----Original Message-----
From: Espen Heitmann

True Rob

And the hot air do rise, but you will get some cirkulation with the heat pump, however so do I think the largest drawback with an RV
heat pump VS one for your home is that it does not recirculate the air.

But an RV heat pump with a heat strip must be better than one without, or ?

Robert Mueller wrote on Thu, 24 October 2013 16:20
> Espen,
>
> I don't have any experience with heat pumps but there is one thing that no one has mentioned regarding the heat strips or heat
pump
> and that is that the hot air is supplied at ceiling level vs. the furnace which puts it out at floor level.
>
> Regards,
> Rob M.
> The Pedantic Mechanic
> USAussie - Downunder
> USA '75 Avion - Double Trouble TZE365V100426
> AUS '75 Avion - The Blue Streak TZE365V100428

[r...@gmcnet.org]

Loffen wrote on Thu, 24 October 2013 02:35

> I am thinking of replacing my original roof AC with a new unit that has a heat pump due to the Norwegian climate.
>
> After some research I did find the Coleman mach 8 with the heat pump and the option for a heat strip wich you can not get on the duo therm in combination with a heat pump.
>
> So has anyone any experience with the Coleman ?

One thing I don't like about a heat pump is all that extra run time you are putting on the a/c unit and they are not very effeciant below around 40 degrees farenheight. If a small electric heater stops working just throw it in the trash and buy another if the heat pump stops its around $1000 or more as most rv shops don't know how to fix it. Most RV shops won't even replace a bad motor they want to replace the whole unit.
--
Roy Keen
Minden,NV
76 X Glenbrook

[Espen Heitmann]

Roy

I am not worried about the run time,and we do not have any shops to go to here if it brakes down anyway, but we are pretty good at repairing out self if it has a brake down.

If it delevers heat betwen 50 to 60 F I would be happy and I would feel a lot safer at night if I do not need to use the gas furniac.

Rob

Yes the amps could be a problem, even if it is only for night time use I guess adding the water heater would be trouble.

--
1973 26' Parrot green Seqouia in Norway
"Loffen" translates to white bread, it is also a nick name for your.. well you know..down there.. and it was my dog's name, but hey you can also call me Espen ;)

[Ken Burton]

Here is the point. With the heat source (the Coleman) mounted in the ceiling, the heat will not make it down to the floor where the people are. Those ceiling mount units are very poor heaters because heated air rises.

The built in furnace or a couple of electric cube heaters do a much better job at heating the interior.

I have 2 of these cheap cube heaters and run them at 1/2 power (750 watts each) when it gets cold. I have run them to at least +20 F out side temperature and they have been more than adequate. If I am camped and not plugged in to shore power then I run the propane furnace.

I do have CO detectors in the coach.

Here is what I'm talking about when I say cube heater:
http://www.walmart.com/ip/Pelonis-Fan-Forced-Heater-with-Thermostat/21804031




--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Rob Mueller]

Espen,

Assuming you have the original thirty plus year old OEM furnace I can understand your concerns running it at night. However, would
it not be possible to disassemble it check it visually for corroded areas and pressurize it to check for leaks in the "combustion
chamber" OR just go buy a new unit?

You can also fit a CO / CO2 sensor in the GMC; speaking of which I believe STRONGLY that every GMC (or any motorhome) should have:

1) Smoke detector
2) LPG detector
3) CO / CO2 detector

Double Trouble had a new furnace fitted in the 1990's and had a smoke detector installed when I purchased it. I added 2) and 3).

If you don't have these detectors you could wake up dead! ;-)

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428

-----Original Message-----
From: Espen Heitmann

Roy

I am not worried about the run time,and we do not have any shops to go to here if it brakes down anyway, but we are pretty good at
repairing out self if it has a brake down.

If it delevers heat betwen 50 to 60 F I would be happy and I would feel a lot safer at night if I do not need to use the gas
furniac.

Rob

Yes the amps could be a problem, even if it is only for night time use I guess adding the water heater would be trouble.

[Kerry Pinkerton]

Although I have heat pumps in my home, I have zero experience with them in the coach. Nor do we have a lot of time in the coach. So take the comments below for what they're worth....an opinion.

We have a Dometic Brisk-Aire (standard AC) with the 1500 heat strip. About the coldest we've been out with it has been down in the mid 30's (F) morning temperature. The Brisk-Aire does not have a thermostat and the fan runs at full speed which really moves a lot of air around. We've not noticed any of the hot spots/cold spots (hot head cold feet) problems that are sometimes present in houses with passive (not fan forced) air handlers. The air handler in the Brisk-Aire seems to be strong enough to keep the air temperature mixed up..

Our AC is in the middle of the coach. At Dothan this spring, we had several cold nights and I also put one of those 1500W quartz heaters on the 'headboard' in the rear bedroom. The wife and I are fairly light sleepers and normally leave the air handler on to provide white noise and block out anything going on outside the camper.

We're probably going to add a second unit for the rear of the coach and it will be one of the heat pump units (with the heat strips)
--
Kerry Pinkerton

North Alabama, near Huntsville,

77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as an Art Deco car hauler

[Erv Troyer]

I will put in my 2 cents worth - here is a post I sent 10 years ago. We still have the heat pump, and still use it, but my opinions haven't changed
<<<<<<<<<<<<< posted 1/2/2003 <<<<<<<<<<<<<<<<<<<<<<
I have installed the Duo-Therm Penguin heat punp in our GMC. I like it, but...

Pros: puts out a LOT more heat than a heat strip. Heat strip is limited to about 5500 btu, but heat pump is at least double that at 50 degrees outside. However, output gets less as outdoor temp goes down.

Cons: Outdoor thermostat shuts off heat pump at 40 degrees to keep it from freezing up, so we still have to keep our furnace. In your area, with your usage of the GMC, you could probably get rid of furnace.

Also - heat pump requires 120 VAC, so you have to plug in, or run the gen-set. Furnace can run from LP and batteries.

Another consideration - when the indoor thermostat is satisfied it shuts off the compressor - the blower keeps running. This blows some relatively cool air into the bedroom, and it feels chilly. We use the heat pump when we leave the coach in the evening, but when we go to bed we turn up the furnace for more comfort and less noise.

Ya' takes yer pick, and makes yer own choice...
<<<<<<<<<<<<< end of post <<<<<<<<<<<<<<<<<<<<<<<<<<<
--
Erv Troyer Lagrange, IN
74 Sequoia
re...@aol.com

[John R. Lebetski]

1)Does the resistance heat strip work along with the heat pump? I thought it was one or the other. So Amps would not add if so.
2)These don't bring in outside air but do recirculate. Evaporator and condenser are different air circuits.
3)I wouldn't worry about compressor run hours in an RV. Disuse periods of time are probably more concerning.

--
John Lebetski
Chicago, IL
77 Eleganza II
Source America First

[Espen Heitmann]

From the manual :

An optional auxiliary electric resistance heating assembly
can be installed to take the chill out of the indoor air when
the heat pump can no longer operate. The heat pump will
shut down at conditions which would cause outdoor coil
freeze-up, generally near freezing temperatures.

http://www.americanrvcompany.com/assets/images/ColemanAir/mach8Op_Main.pdf

John your # 2, no the RV heat pump do not recirculate, the home units do.

Rob

I will of course keep my furnace, and yes it is the original suburban, I hace checked and cleand it and it is in really good condition.

And yes there will be detectors in the GMC.

Erv

"Another consideration - when the indoor thermostat is satisfied it shuts off the compressor - the blower keeps running. This blows some relatively cool air into the bedroom"

That is the reason why am thinking of the Coleman unit, it is the only one I have found with the heat strip, sure it will not be very warm when the compressor shouts down, but it will not be freezing either.

--
1973 26' Parrot green Seqouia in Norway
"Loffen" translates to white bread, it is also a nick name for your.. well you know..down there.. and it was my dog's name, but hey you can also call me Espen ;)

[Johnny Bridges]

I think you got it backwards. My Dometic - and its predecessor and my SOB - are total recirculate. They don't bring in any outside air at all. At times, my home system does.

--johnny

[Espen Heitmann]

Darn, I think you are right Johnny :blush:
Had to look over the plans a couple of times but it looks like it is recirculing.. my bad.

[Rob Mueller]

Espen,

Kinda figured you'd checked the furnace, when I was at a Great Lakers Rally someone made a presentation on the OEM furnace and they
had a sample that wasn't it very good shape, there were holes all through the "firebox" which made it dangerous. The owner did not
have a CO / CO2 alarm or LPG alarm and he wasn't aware of its condition until he removed the unit and checked it.

Whoever wrote up the Coleman manual hit the nail on the head vis-à-vis the heat strip from my experience when they noted that they;
"take the chill out of the indoor air."

I clicked on the link to the manual you provided as I was wondering how the heat pump and heat strip interacted and found this:

"The heat pump will operate on reverse cycle refrigerant heating at outdoor temperatures above freezing. When the outdoor
temperature is below freezing, the heat pump compressor will shut down to prevent outdoor coil freeze-up. At this time, if the
optional auxiliary electric resistance heater has been installed, it will be energized to take the chill out of the indoor air. The
electric resistance heater is not a substitute for a furnace at these low outdoor temperatures."

Now I understand your desire to get a Coleman heat pump type unit, when the OAT is in range you use the heat pump to heat the GMC.
When the OAT is out of range you use the furnace and the heat strip provides ~ 5000 BTU towards your heating needs which would cut
down on the amount of propane you use. We have did the same thing effectively by turning on the heat strips and the furnace when we
were at the KOA outside Niagara Falls several years ago.

The following paragraph demonstrates an acute grasp on the obvious!

In reality how comfortable the heat strip can keep a GMC is a function of the OAT and how well your GMC is insulated or it's overall
R factor. If you have only the OEM spray in insulation it isn't worth a damn! However, at Santa Rosa I saw a beautiful GMC that took
the owners, Gene and Diana Ewankiw, seven years to restore. They removed all the OEM spray insulation and re coated the interior
with the blue spray in insulation used all over Canada. Gene scraped it to a uniform thickness all over the coach. They noted that
it took very little to heat it in the winter and very little to cool it in the summer. I did some checking and evidently spray in
foam can have an R value of up to 6 per inch of depth which would be pretty good for a GMC body. You will loose a hell of lot more
heat through the windows and various vents.

At the end of the day I'm in KenH's camp - "I ain't goin' nowhere that requires a furnace on purpose!" ;-)

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
USA '75 Avion - Double Trouble TZE365V100426
AUS '75 Avion - The Blue Streak TZE365V100428


-----Original Message-----
From: Espen Heitmann

From the manual :

An optional auxiliary electric resistance heating assembly can be installed to take the chill out of the indoor air when the heat
pump can no longer operate. The heat pump will shut down at conditions which would cause outdoor coil freeze-up, generally near
freezing temperatures.

http://www.americanrvcompany.com/assets/images/ColemanAir/mach8Op_Main.pdf


John your # 2, no the RV heat pump do not recirculate, the home units do.

Rob

I will of course keep my furnace, and yes it is the original suburban, I hace checked and cleand it and it is in really good
condition.

And yes there will be detectors in the GMC.

Erv

"Another consideration - when the indoor thermostat is satisfied it shuts off the compressor - the blower keeps running. This blows
some relatively cool air into the bedroom"

That is the reason why am thinking of the Coleman unit, it is the only one I have found with the heat strip, sure it will not be
very warm when the compressor shouts down, but it will not be freezing either.