Roof A/C

[Bkurt]

I have a 2005 Montana in great condition, but
Its time to replace the front A/C unit before it dies

Any suggestions what to replace it with?

Kurt

[rohrmann]

I'm thinking if the unit has failed, replace it with a unit that is compatible with the thermostat system already in the rig. Why is it about to die?

[Bkurt]

still works ok. Just thought after 18 years its time to think about it.
Thanks for the info

[Carl n Susan]

Isn't the A/C in a 2005 model Montana the non-ducted type? The controls for it are on the face of the A/C and it is not tied into the thermostat. The 2005 era had that POS "Remote Control" thermostat and wasn't a multi-zone one as I recall.
Anyway if you have a non-ducted A/C, then any non-ducted A/C can replace it.

[DutchmenSport]

If it's working fine, then why replace it? It's probably in better shape, better made, and will continue running when a brand new one now, will be in the junk yard someday. That one will still be "ticking" and taking the "licking!"

[Bkurt]

it is ducted and has a wireless remote

[Bkurt]

Well the only issue when its extra hot it draws extra amps and trips the breaker but I blow a little fan over the breakers and it helps.

[Carl n Susan]

It is great that the front bedroom A/C is tied into the duct. But does the thermostat have multiple zones to control the bedroom A/C or does it have it's own panel to control it?
The Wireless Remote Thermostat is no longer manufactured (thank goodness). It has a component in the A/C it uses to turn it On/Off. You will be hard pressed to find a current A/C that will work with that thermostat.

[Carl n Susan]

Is the A/C controlled by the Remote Control Thermostat or does it have its own control panel on the face of the A/C?

Any replacement will work with the duct system. Hopefully your A/C has its own control panel. If it is controlled by the Remote Control Thermostat then you likely have issue(s). That thermostat has not been made for years (thank goodness). It has a component in the A/C it communicates with operate the A/C. New A/Cs won't have it. You probably will have to change thermostats.

Here is a link to a very old and long discussion about the Remote Control Thermostat. The last couple of pages have Posts from members and their recent experiences finding a replacement. Remember the furnace is also impacted by a chnage in thermostats, not just the A/C(s).
https://www.montanaowners.com/forums...ead.php?t=8145

[Bkurt]

Yes the bedroom A/C has a manual control swith on the unit. Its still working fine. The big unit im thinking of replacing has the useless little handheld thermostat thats not very accurate. My main objective is asking if anyone has replaced their unit and if thay are happy with there decision.
Thanks all for your input.

[Carl n Susan]

Originally Posted by Bkurt

Yes the bedroom A/C has a manual control swith on the unit. ...

Sorry! When you wrote "..front A/C.." I assumed you meant the front bedroom A/C. My bad.

Good luck changing the main A/C unit.

[RRman]

I had to replace my 2005 Big Sky Rear/Main Ducted AC with the little silver remote in 2011 - we live in our RV at LEAST 6 months annually. A new at the time Dometic Brisk Air was installed by myself along with a new Dometic Single Zone Thermostat. The instructions for connecting a new AC to a new Thermostat are fairly straightforward as the wires are color coded. Not having 50Amp power at home I did take my RV to a dealer and paid a small fee to have them plug in my RV in and test my work - it PASSED.
Newer Dometic Single Zone Thermostats are on Amazon - less than $60.
That Brisk Air is still working fine.
And we've also added a low Profile Bedroom AC - which we're on our second one - a Penguin vs the Coleman Mach that only lasted 7 years of light use... Have also had to replace the Converter and front jacks and the Furnace a few years ago - I suppose since we use our old 2005 Montana so much every year...

[firestation12]

Consider the Gree Eco-Cool. Gree is perhaps the largest mfg of ac products. The Eco-Cool unit has an inverter compressor that uses 1/3 less amps, is quieter, can be controlled by smart phone WiFi, has a redesigned blower that the improves circulation, doesn’t need a soft start, and is priced to be competitive with Dometic, Coleman and other brands. Comes with a 2 year warranty

[Bourbon County]

It is a physical fact that an AC will draw more current the higher the outdoor temps are. Typically, you should see maybe 5-6 more amps at 95 degrees than 75 degrees. ACs are less efficient when you need them the most. That's still well below a 20 amp breaker rating.

One thing I find concerning is that by blowing a fan across the breaker box, it will help. I'm wondering if you're generating a lot of heat in the breaker box. It might be a really good idea to open it up and check your wire terminations on the breaker and also the neutral for that circuit. This could possibly be the source of the additional heat.

If you haven't done maintenance on the unit lately, it would pay to clean the coils and go ahead and replace the capacitor. Both of these items can contribute to higher amp draw.

I would be reluctant to just replace the unit until all of the maintenance items are done. As stated, you very likely won't get a better unit now. If you do replace the unit, buy the old one a gold watch and a villa in a retirement village; it's served you well.

[Bourbon County]

Originally Posted by firestation12

Consider the Gree Eco-Cool. Gree is perhaps the largest mfg of ac products. The Eco-Cool unit has an inverter compressor that uses 1/3 less amps, is quieter, can be controlled by smart phone WiFi, has a redesigned blower that the improves circulation, doesn’t need a soft start, and is priced to be competitive with Dometic, Coleman and other brands. Comes with a 2 year warranty

Thanks for the information on the Gree units, I didn't even know that they were available. I haven't done a real deep dive on them yet, but it appears that the inverter is only used for starting and it's not a truly variable speed unit. I've always thought the RV AC manufacturers could learn a great deal from the mini-split manufacturers, this is a giant step forward in my opinion. The true variable speed residential units modulate the compressor speed, refrigerant flow and blower speed. There seem to be more manufacturers getting into this market which I think is great; should spawn more innovation and competitive markets. Seems like Coleman and Dometic are about the only widely used OEM units and I question if a particular unit is chosen for it's quality or just the lowest bidder.

[firestation12]

Originally Posted by Bourbon County

Thanks for the information on the Gree units, I didn't even know that they were available. I haven't done a real deep dive on them yet, but it appears that the inverter is only used for starting and it's not a truly variable speed unit. I've always thought the RV AC manufacturers could learn a great deal from the mini-split manufacturers, this is a giant step forward in my opinion. The true variable speed residential units modulate the compressor speed, refrigerant flow and blower speed. There seem to be more manufacturers getting into this market which I think is great; should spawn more innovation and competitive markets. Seems like Coleman and Dometic are about the only widely used OEM units and I question if a particular unit is chosen for its quality or just the lowest bidder.

I didn’t see any indication either, that the compressor utilizes variable speeds as the residential units do, but I’m wondering how an inverter that converts 120 volts alternating current to DC would only be used to start but not run the compressor. I didn’t see that mentioned in the ad video. Did I miss something?

[Bourbon County]

Originally Posted by firestation12

I didn’t see any indication either, that the compressor utilizes variable speeds as the residential units do, but I’m wondering how an inverter that converts 120 volts alternating current to DC would only be used to start but not run the compressor. I didn’t see that mentioned in the ad video. Did I miss something?

Actually an inverter converts a DC voltage to AC. The industrial inverters rectify the incoming AC voltage to DC and then oscillate out an AC voltage. They vary the frequency and voltage for speed control. These inverters are very flexible and offer many options including acceleration and deceleration ramp times, torque boost, stall protection, etc. Frequency is the speed control for an AC motor. The inverters commonly used to power appliances on an RV utilize the already available DC voltage and oscillate out a fixed 60 HZ and 120 volts; they are much simpler.

Soft starts for 3 phase motors have been around for some time. It's a very simplified inverter that offers limited options for acceleration and declaration times. Once the acceleration ramp up time is reached, it has a contactor that just connects it to line voltage and frequency bypassing the SCR. These are useful if the electrical system is loaded and also very useful if it's driving a load that can have slack in it like a chain conveyor. I suspect this is what Gree is doing.



By nature, a 3 phase motor is much simpler to start than a single phase. There are soft starts utilizing this technology available for residential ACs and heat pumps. They are pretty expensive and not commonly seen. There's always the warranty issue using a third party device; it's always the root cause even if a meteor falls on the unit!

I do Gree's efforts and the next step to a true variable speed unit should be a baby step rather than a quantum leap. If only the RV manufacturers would realize if they would give up just an inch or so in ceiling height and make the ducts bigger along with less restrictive diffusers it would likely solve a lot of problems with RV AC.

[Mark7]

Originally Posted by firestation12

Consider the Gree Eco-Cool. Gree is perhaps the largest mfg of ac products. The Eco-Cool unit has an inverter compressor that uses 1/3 less amps, is quieter, can be controlled by smart phone WiFi, has a redesigned blower that the improves circulation, doesn’t need a soft start, and is priced to be competitive with Dometic, Coleman and other brands. Comes with a 2 year warranty

Can you point me to the one you used? I looked at their site and only saw mini split systems.

Thanks!

[2 Yoopers]

Originally Posted by Mark7

Can you point me to the one you used? I looked at their site and only saw mini split systems.

Thanks!

Premier Products has them listed for sale. Google search Gree rv air conditioner and you will see Premier.

[firestation12]

Do a Google search using “Gree eco-cool” spelled exactly like what’s between the quotation marks, will yield photos and links that look like your present roof ac. You’ll also see 4 videos that will add to your information search.