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Topic: Air Conditioner
Posted By: PhilR on 07/22/17 06:31am

I just installed a Coleman Mach 8 9,200 BTU AC unit on my Northern Lite truck camper. The camper was prep'd for ac from the factory. The front of ac unit is fastened to the roof at the former roof hatch opening, which is about an inch higher than the roof elevation which causes the rear of the ac unit to be cantilevered and unsupported. Not sure if I need to provide additional support between the bottom of the ac unit and the roof. Anyone else experience this problem?

Posted By: c.traveler2 on 07/22/17 07:00am

Could you post some photos so we can see what the situation looks like.

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Posted By: SidecarFlip on 07/22/17 07:17am

I'm curious as well. Considering installing a low profile Dometic unit and my rear vent is labelled 'AC prep'.

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Posted By: gbopp on 07/22/17 07:36am

Can you build it up with composite lumber or something similar?

Posted By: Reddog1 on 07/22/17 07:50am

I installed the Polar Cub on my Bigfoot. It sandwiches the roof between the inner mounting plate and the A/C frame. It only needs to seal where the foam gasket contacts the roof. The Bigfoot roof is curved, so side to side the A/C really only touches where the hole is plus about 4-inches.

Wayne

Posted By: AnEv942 on 07/22/17 11:47am

Ours the roof slopes starting about 2" from hole. Important is the hole itself if flat. But the end of our AC is a almost an inch off roof. Gasket kit included a strip for rear support, as I recall I moved it closer to hole so just shy of contacting roof (like it would if roof flat) before compressing gasket.
Our original AC was larger, the rear support strip didn't contact roof at all and it didn't leak or other ill effects from lack of support after 10 years.
[image]
View showing roof slope
[image]
Not best picture, just showing start of roof transition from hole.

Its the 4 mount bolts that hold AC to roof, compressing gasket-
I don't 'think' non-supported rear could cause a leak. I just didn't like of idea of it hanging and bouncing down the road. Possibly- likely wouldn't move though. If you added something just ensure it doesn't hold the unit up from compressing the gasket.

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Posted By: Old-Biscuit on 07/22/17 01:41pm

A/C unit is self supporting

Roof gasket needs to be compressed by 1/2 of thickness but not overtightened.

Tighten mounting bolts by hand then SNUG them up using a wrench.....'X' pattern

SNUG.......
40 INCH POUNDS if you have an INCH torque wrench (NOT FOOT POUNDS)
Otherwise SNUG. Which is just a little resistance when turning with wrench

If you overtighten ---gasket can get crushed, evap coil drip pan drain holes can get blocked (too close to roof) and then condensate will run inside rig and/or roof could wrap causing leaks from rain etc.

SNUG!

Is it time for your medication or mine?


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Posted By: PhilR on 07/22/17 02:04pm

Thanks for all the input. The camper roof is raised near the roof hatch opening that is used for the ac install. When the 4 long bolts are tightened and compress the 1" gasket, the ac unit is drawn down to the "stop" mark and that is the only contact with the roof. Because the gasket is at the front end of the ac unit, the back end is cantilevered almost 2" off the roof and unsupported. This is a low profile unit and is 3 to 4 ft long. The unit has 3 pads similar to the gasket materiel that are fastened to the underside that appear to be intended to support that end of the ac unit, but are too thin, leaving approx. a 1" space. I think that I should look for the same gasket materiel and glue it to the existing pads so the unit is fully supported.

Posted By: SidecarFlip on 07/22/17 02:06pm

I seem to remember reading somewhere, where the supplied mounting bolts are too long.

Posted By: GeoBoy on 07/22/17 02:09pm

PhilR wrote:

Thanks for all the input. The camper roof is raised near the roof hatch opening that is used for the ac install. When the 4 long bolts are tightened and compress the 1" gasket, the ac unit is drawn down to the "stop" mark and that is the only contact with the roof. Because the gasket is at the front end of the ac unit, the back end is cantilevered almost 2" off the roof and unsupported. This is a low profile unit and is 3 to 4 ft long. The unit has 3 pads similar to the gasket materiel that are fastened to the underside that appear to be intended to support that end of the ac unit, but are too thin, leaving approx. a 1" space. I think that I should look for the same gasket materiel and glue it to the existing pads so the unit is fully supported.

That is what I would do, just to keep the AC from ocellating front to back.

Posted By: Old-Biscuit on 07/22/17 03:22pm

Once hold down bolts are SNUG and roof gasket properly compressed the A/C unit is 'self-supporting'

In other words.........
A/C pan should NOT touch RV roof and does NOT need supporting

A/C Unit (Coleman Mach 8) needs to be level or up to MAX of 15* nose high when RV is sitting level.

Posted By: Reddog1 on 07/22/17 06:44pm

PhilR wrote:

... I think that I should look for the same gasket materiel and glue it to the existing pads so the unit is fully supported.
I think you will be creating a problem where there is none. Before I did that, I would call Northern Lite. If you are wrong, you may create a leak in the ceiling which at best will leave very ugly water stains which cannot be removed. A phone call is pretty inexpensive.

Wayne

Posted By: noteven on 07/23/17 11:56am

Off topic questions: Will a single Honda 2000i generator start and run the air conditioner the OP is installing?

Posted By: SidecarFlip on 07/23/17 12:01pm

Reddog1 wrote:

PhilR wrote:

... I think that I should look for the same gasket materiel and glue it to the existing pads so the unit is fully supported.
I think you will be creating a problem where there is none. Before I did that, I would call Northern Lite. If you are wrong, you may create a leak in the ceiling which at best will leave very ugly water stains which cannot be removed. A phone call is pretty inexpensive.

Wayne


Wayne has the correct approach and NL will steer you right.

Posted By: SidecarFlip on 07/23/17 12:05pm

noteven wrote:

Off topic questions: Will a single Honda 2000i generator start and run the air conditioner the OP is installing?


Not off topic at all and a legitimate question... I don't believe it will. The 2000I, 2000 is maximum watts not running watts.

Posted By: Reddog1 on 07/23/17 12:27pm

noteven wrote:

Off topic questions: Will a single Honda 2000i generator start and run the air conditioner the OP is installing?
It should run the A/C, but not the heat strip.

From the Spec sheet. Cooling the compressor requires 8.9 amps, and the high I.D. motor (fan) is 1.2. A total (maximum) of 10.1 amps. The specs say O.D. motor is 1.6. I don't know what the O.D. motor is.

The Honda 2000 output is 13.3 amps, from the spec sheet. So, that leaves you with about 3.2 amps to spare.

I have a Polar Cub which requires a maximum of 9 amps. The Honda runs the Cub just fine. I run the Honda in the Eco mode.

Wayne

Posted By: markchengr on 07/23/17 02:54pm

On my Northern Lite the air conditioner is mounted on a transition piece of fiberglass which extends the weight out away from the roof opening. I have seen them installed this way on every NL that I have ever seen. I think you should check on this prior to trying to install directly to the roof. Might save you some headaches later.

Posted By: Reddog1 on 07/23/17 02:59pm

markchengr wrote:

On my Northern Lite the air conditioner is mounted on a transition piece of fiberglass which extends the weight out away from the roof opening. I have seen them installed this way on every NL that I have ever seen. I think you should check on this prior to trying to install directly to the roof. Might save you some headaches later.
Another reason I would call Northern Lite. .

Posted By: GeoBoy on 07/23/17 06:38pm

I have no problem running my Mach 8 9.2 with a Honda 2000i.

Posted By: towpro on 07/23/17 08:25pm

I also have no problem running the mach 8 9.2 that came on my 2016 Arctic Fox 990 with my Honda EU2000. It will even start the AC in Eco mode but the overload light sometimes will flash. I have used my AC/Honda 2000 between sea level and around 1000'.

When using my AC on generator, I do make sure the hot water heater is running on GAS as well as refrigerator. Just to give the max electric to the AC. But I don't turn off the camper battery charger.

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Posted By: noteven on 07/23/17 09:09pm

Reddog1 wrote:

noteven wrote:

Off topic questions: Will a single Honda 2000i generator start and run the air conditioner the OP is installing?
It should run the A/C, but not the heat strip.

From the Spec sheet. Cooling the compressor requires 8.9 amps, and the high I.D. motor (fan) is 1.2. A total (maximum) of 10.1 amps. The specs say O.D. motor is 1.6. I don't know what the O.D. motor is.

The Honda 2000 output is 13.3 amps, from the spec sheet. So, that leaves you with about 3.2 amps to spare.

I have a Polar Cub which requires a maximum of 9 amps. The Honda runs the Cub just fine. I run the Honda in the Eco mode.

Wayne


Thanks Wayne - a Polar Cub would very likely be enough in my Snowbird 810 - I don't use it in temps much above 90F...at 3500 - 5000 ft

Posted By: Reddog1 on 07/23/17 10:18pm

It is my understanding the Polar Cub is no longer available. I was not very clear on my post, the specs were for the Coleman Mach 8 9,200 BTU AC unit.

I think the Coleman Mach 8 9,200 BTU AC unit is the replacement for the Polar Cub.

Wayne

Posted By: WyoBull on 07/24/17 09:56am

I would call Northern Lite directly as I do know there is a mount kit from NL our dealer used between the roof and the AC unit when they installed ours.

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Posted By: PhilR on 07/24/17 03:46pm

My NL camper has the fiberglass section (mount kit) that is designed to distribute the weight of the ac over a broader area. It comes on units that are factory "ac prepped". This is why the ac unit sits a little higher above the roof, and the 3 support pads on the underside of the rear part of the ac unit are too thin to fill the space and provide proper support. I am waiting for a call back from NL, but plan to remedy this situation in any event.

The Honda 2000 will run the Mach 8 9,200 ac unit with no problem.

Posted By: SidecarFlip on 07/24/17 03:48pm

PhilR wrote:

My NL camper has the fiberglass section (mount kit) that is designed to distribute the weight of the ac over a broader area. It comes on units that are factory "ac prepped". This is why the ac unit sits a little higher above the roof, and the 3 support pads on the underside of the rear part of the ac unit are too thin to fill the space and provide proper support. I am waiting for a call back from NL, but plan to remedy this situation in any event.

The Honda 2000 will run the Mach 8 9,200 ac unit with no problem.


"The Honda 2000 will run the Mach 8 9,200 ac unit with no problem" I bet it won't power anything else at the same time.

Posted By: Reddog1 on 07/24/17 04:37pm

SidecarFlip wrote:

PhilR wrote:

My NL camper has the fiberglass section (mount kit) that is designed to distribute the weight of the ac over a broader area. It comes on units that are factory "ac prepped". This is why the ac unit sits a little higher above the roof, and the 3 support pads on the underside of the rear part of the ac unit are too thin to fill the space and provide proper support. I am waiting for a call back from NL, but plan to remedy this situation in any event.

The Honda 2000 will run the Mach 8 9,200 ac unit with no problem.


"The Honda 2000 will run the Mach 8 9,200 ac unit with no problem" I bet it won't power anything else at the same time.
No, but that was not the question.

Wayne

Posted By: PhilR on 07/25/17 11:48am

Northern Lite factory is on a two week vacation. Nobody available to answer my question. Customer service when convenient I guess. Several RV shops advised that they add additional foam to support the rear of the ac unit when installing on Northern Lite campers.

Posted By: Kayteg1 on 07/25/17 11:58am

Reddog1 wrote:

SidecarFlip wrote:

PhilR wrote:

My NL camper has the fiberglass section (mount kit) that is designed to distribute the weight of the ac over a broader area. It comes on units that are factory "ac prepped". This is why the ac unit sits a little higher above the roof, and the 3 support pads on the underside of the rear part of the ac unit are too thin to fill the space and provide proper support. I am waiting for a call back from NL, but plan to remedy this situation in any event.

The Honda 2000 will run the Mach 8 9,200 ac unit with no problem.


"The Honda 2000 will run the Mach 8 9,200 ac unit with no problem" I bet it won't power anything else at the same time.
No, but that was not the question.

Wayne

2000W gives 16 amps.
My 12k AC draws 6.7 amp when running, so I would not hesitate to switch generator ECO off and run small oven as well.
But if you are in weather where AC cycles and it would happen in that moment, it all will go into stall.




Posted By: Reddog1 on 07/25/17 01:41pm

Kayteg1, you may consider contacting Honda and correcting them on their specs for the Honda 2000. The information I posted is from their spec sheet. I am sure they would be appreciative considering all of the engineering they have done.

Wayne

EDIT: I have a Polar Cub, Honda 2000, Microwave, and a 55 amp Iota Charger. I have had all of these over ten years, including the spec sheets and personal experience.

* This post was edited 07/25/17 02:17pm by Reddog1 *

Posted By: Kayteg1 on 07/25/17 01:43pm

Honda makes their specification on assumption the user is going be an idiot.
We are not idiots and can evaluate the situation. Read my note about restarting AC.

Posted By: Reddog1 on 07/25/17 01:52pm

Kayteg1, it appears to me you are of the belief you are an expert on every subject. I have no reason to believe Honda makes their specifications on assumption the user is going be an idiot. I think it is to protect the users from idiots. This threat need not drift into a discussion on idiots, so I will leave it at that.

Wayne

Posted By: jimh406 on 07/25/17 01:52pm

Kayteg1 wrote:

Honda makes their specification on assumption the user is going be an idiot.


Obviously, Honda needs to get their act together. Oh wait, they are the most well thought of generator on the planet. [emoticon]

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Posted By: Kayteg1 on 07/25/17 02:00pm

I am no expert on anything, but I read and remember.
When this forum has lot of members worrying about carrying 3000 lb camper on 3/4 tons, you will find farmers saying that they haul 30,000 lb with their trucks.
Sure they are smart enough to not go on freeways with such loads, so it all boils to common sense.... or simple trying. I don't own Honda 2000, but any owners willing to make simple test?

Posted By: Reddog1 on 07/25/17 02:11pm

Perhaps you should state when you are making comments based on what you have read and what you have experienced. If it is something you read, identify the source. Many of us read a lot but do not make our posts in such a way it appears we are posting from experience. We also do not have the need to post on every subject from what we have read implying our posts are from experience.

Wayne

Posted By: Kayteg1 on 07/25/17 06:31pm

That sounds like you don't believe members will understand why 16amp is much more than 6.7 amp.
I have faith in members intelligence and let them do the final tests.

Posted By: AnEv942 on 07/25/17 09:08pm

Could be that the handful of AC units I've seen removed were improperly installed. They all had the rear foam strip attached. The only way I could see causing a leak is if it were to thick and interfered with the compression of gasket. Only using it to limit free movement of cantilevered end, pan may not need it but at least in my eye, my roof wouldn't resit the leverage. Many replacement gasket kits come with extra strip(s)?

The smaller dense squares, Ive only seen mention as a means to prevent over compression-though they are so thin cant see how that works.

If a phone call was to be made wonder what Dometic might suggest (or why the extra strip was included with mine). Curious

Noted on the newer NLs raised areas on roof under AC- if AC doesnt make contact what purpose would they serve?

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