Air Conditioning Malfunction?

[obiwancanoli]

I have a 2017 Newmar Ventana LE which, due to warranty and repair issues, has not seen weather requiring the use of my a/c system, and until this past weekend, had no need to use it. However, a camping trip to a climate where the outside temps were 100 degrees + also saw inside temps of 95, despite all efforts to cool the inside of the RV, starting at 9 am, and running all day long, and into the night.

The thermostat is a 2-zone system (dual a/c units on top) which, among other modes, includes "Cool" and "Auto". Neither of these modes resulted in anything akin to a/c cooling, although the fans pushed cool-ER air through the system, just not AIR CONDITIONING cool... by comparison, I also ran the a/c system in the cockpit dash, and that works just fine... it's just not designed to cool the entire RV.

I know it worked at one time, since I spent a couple nights in the rig at the time I purchased it, and the a/c system was freezing me out (I was new to the lifestyle, with my first RV, and hadn't properly set the unit).

I've gone over everything I know to figure out and resolve this, and though unsuccessful, hope to do so before my next trip to a warm/hot clime.

Does anyone have a thought on what I'm missing here? Or is it possible I have TWO defective a/c units?

[2bzy2c]

Excellent thread. Thanks for keeping us updated.

[down_home]

We have a problem with the sensor kicking the the second system, the front Heat pump system down or off first system is the rear unit. due to light 2 ft away and air trapped in that area. The system shares cooling and heating between the to units. We find that setting the front unit or 2 a couple degrees cooler than front.
You front unit 2 on ours, anyway, has kicked down to low on auto, it sounds like.
Try the unit on high and see i it doesn't freeze you out.
We are sitting her with our front unit making a fluttering noise and no heat of cool after a minute or two operation. The reversing valve, if that if what it is called is toast. Refrigerant is not going in either direction much.
You should be able to operate both units on 30 amp. Ours will shed load if too many amps or power is being consumed. But...not all units do that. I watch the load panel and when operating properly both 15,500 units draw 24 amps except when starting, or 12 amps each. Both units won't kick their compressors on at the same time,because it could/would cause problems but don't know about yours.
Try your heat pumps on the generator or 50 amps. On 30 amp turn off both units and start the front unit and see how it performs. Then kick on the rear unit and watch the amps.
You didn't mention noise so it does sound like the unit is operating on low setting, since it is putting out some cool air. Your sensor may be doing it or the thermostat and since I'm no ac expert call a mobile tech cheaper than a Dealer sometimes and ac work is one of their biggest demands.

[obiwancanoli]

Just a quick update for you... turns out both a/c units on top weren't working at full power... tech said they were operating at about half capacity, and thus, required replacement. Also turns out Dometic has a 2 year warranty on these, so their replacement was covered without cost to me.

Happy to note both units working chillingly! Heard compressor come on within a minute of turning on the a/c ("Cool" on the Dometic control panel), and shortly thereafter, it got really cold, really fast.

Of course, now that the season is cooling off, I have no need for the a/c until next summer, but it's no longer an issue. Thanks to everyone for your help, insight, and advice.

[obiwancanoli]

wa8yxm wrote:
Ah. the sweetest sound a Service consultant can make "Covered under Warranty"

Don't you just love it 🙂

You betcha, Bucko... they're in, soon to be installed, and all else looks good... batteries are fine... more relief... now... if I can just get the **** thing back while the weather's still cooperating!

[wa8yxm]

Ah. the sweetest sound a Service consultant can make "Covered under Warranty"

Don't you just love it 🙂

[obiwancanoli]

Update:

Turns out, both a/c units are bad, and will be replaced under warranty (Dometic)... Took RV in for service issues, a/c among them, and tech noted my observations were correct, air flow wasn't cooling as it should, said something about power flow showed both were putting out only about half of what they should be. Since they are covered under warranty, he ordered two to install once received, and, presumably, this will solve the problem...

[opnspaces]

You definitely need new batteries, but the bigger question is what is the time frame to get the AC looked at under warranty? If you're getting close to the expiration I would take it in and worry about the other parts later. You can replace the batteries yourself beforehand, or have the dealership replace them for you.

[wa8yxm]

12.6 is resting voltage full charge. The chassis batteries being 12.6 means you likely do NOT have a bi-directional isolator.. You need to confirm this with RV body builder and if you do not add a Tric-L-Start to keep them topped off.

13.2 is a bit low for float voltage on teh house batteries They may still be charging..

How much fluid did the batteries take (Do not answer that) were the plates seriously exposed? If only the top say quarter inch (or less) you may be OK but if you can't even even see the fluid level when you pop the cap as the other party said .. Replace 'em

now if they are six volt GC batteries (Looks like they are from the specs you gave) there are two pair. Each pair is wired like this

Frame---(=6v+)-----(-6v+)--- 12 volt to RV

Think of those (each pair) as thou it were a SINGLE 12 volt battery, because properly connected that is exactly what they are.

[4x4van]

Since you have to be on 120VAC in order to run the A/C, then the condition of your batteries should be irrelevant; when plugged in (or on generator), your converter is providing the 12vdc that your A/C controls need, not the batteries, although I suppose that it is possible that a bad cell or battery could be drawing the voltage provided by your converter down so far as to cause problems. Disconnect the batteries entirely and try the A/C.

[dougrainer]

1. Your AC units will still operate down to about 11.4 volts. The Manufacturer rep was wrong
2. IF the battery plates were exposed at all, REPLACE all 4 batteries. You will never have piece of mind until you do. Doug

[obiwancanoli]

I may have found my problem...

First, I called the manuf. and was told that if the battery power falls to 12.5V or lower the a/c shuts down. This prompted me to start looking at the batteries, and though the chassis batteries (2) are maintenance-free, the House batteries are wet - I was told when I purchased the RV Nov 2017 that the house batteries were maintenance-free.

All but once I have been plugged into shore power. The one time I was not - July 2018 - was a week dry camping, which required frequent generator use, as batteries did not maintain power through the night. Foolish of me not to have checked them, but I confess, and consider the experience a valuable one.

Moving along, checked batteries, all needed fluid, and once filled, took a 90-min ride to assist in a minor recharge, hoping to see a difference upon my return. Following that, Solar kicked in 3 days to charge, and both the RV metering system, and the Solar Controller showed 13.1+ V.

Then, currently plugged into shore power last 24 hours-36 hours. RV meter (fluid levels, etc.) currently shows 12.6V Chassis, and 13.2V House battery charge, and Solar Controller also shows 13.2. When I press the Amp/Volt button on the controller, Volt reading changes to 1.3A, and pressing again, shows 42.4 ah. There's a status bar showing 100%, with the status bar - normally scaling left to right very fast - now static.

Each House battery -4- label shows 115 min @ 75 Amps, 225 Ah @ 20 Hr...

I'm not knowledgeable enough here to KNOW what this means, but if I had to guess, I'd say something's wrong with my batteries... it appears they are not holding a full charge, and never will, due to my failure to check them periodically. With only 42ah showing on the monitor, it's not consistent with what the battery label is telling me, and it seems they need to be replaced...

Am I wrong?

[dougrainer]

obiwancanoli wrote:
OK, here's a new development... I'd been trying the a/c a few times since my initial post, withalways the same results - no a/c... listening for the compressor(s) to come on, and it never did... So, today, I'm back in the same situation, only this time, I'm watching the display on the control unit, which for a Dometic unit, shows "E7" - an error code... so I look up the error code, and the manual states as follows: "Loss of 120 Vac power to all power module boards on the system. The system will shut down."

Now, I've checked the circuit breaker (20A), turned it off, then back on again...still no a/c... what else should I be checking?

E7 means there is NO 120 volts at the AC control board. Does NOT mean there is a problem with your Circuit Breaker. So, when this happens you do reset the AC circuit Breaker. Then if E7 remains you check the bottom of the 20 amp breaker to make sure power is present and the wire is connected and/or not burnt loose. IF OK, then you have to go to the upper AC control board and check the 120 wire connections at the Board housing. It is probably as simple as a loose 120 volt wire nut . Doug

[down_home]

Twenty amp circuit breaker is not larg enough. Either there two or another larger breaker. usually or maybe just sometimts one AC is one circuit and the other ac on the other.50amp is to 50 amp circuits or legs with one common ground.
Two fifty amp circuits not two combined 50 amp circuits into 100 amps.

[obiwancanoli]

OK, here's a new development... I'd been trying the a/c a few times since my initial post, withalways the same results - no a/c... listening for the compressor(s) to come on, and it never did... So, today, I'm back in the same situation, only this time, I'm watching the display on the control unit, which for a Dometic unit, shows "E7" - an error code... so I look up the error code, and the manual states as follows: "Loss of 120 Vac power to all power module boards on the system. The system will shut down."

Now, I've checked the circuit breaker (20A), turned it off, then back on again...still no a/c... what else should I be checking?