86 outside - 82 inside - AC running all day?

kwilkins · 08-21-2016, 05:15 PM

2017 Sunova 36z with 2 heat pumps. This morning the AC's (both set at 70) started running non stop when it was 77 degrees outside. The temperature in the RV keep rising throughout the day; with both units continually running. The high today was 86 (Cape Hatteras, NC) and inside the RV it is still 82 degrees.

There is "coldish" air blowing through all the roof vents. I don't know if it is not as cold as it should be. We traded in a 2010 Sunstar that also had 2 heat pumps that kept the RV cool in weather like this, and even hotter. The Sonova is 4 feet longer and much bigger inside with 3 slides.

Does this sound normal to you, or do you think we have a problem?

Thanks for any advice on this.

Ken

Floridakamper · 08-21-2016, 06:10 PM

It sounds like the same cooling I'm getting on a one week old Suncruiser 38Q. 92 degrees outside and 85 inside. Two 13.5 heat pumps on the roof. My trade, a Newmar had no problem cooling a similar size coach. The dealer said the AC's are working properly.

Lv2Roam2 · 08-21-2016, 06:18 PM

I think you have a problem. Where to start is a real dilemma. Some random approaches to consider:
- Is the t-stat properly set? If you have zones is each one separately turned on to 'cool, auto or high?'
- Is your power source sufficient to start / run both A/Cs? 30 amp might run both with nothing else tUrned on...50 amp is best. Should try running generator and attempting A/C restart.
Start with these and let's see what happens...

Lv2Roam2 · 08-21-2016, 06:38 PM

Bob
Certainly appreciate what your dealer says, but - try putting a thermometer of some sort up against one of the main vents (tape it in place)...if you don't get a reading of ~ 20 degrees less than the outdoor ambient temp you should talk with the dealer again. You should also open a ceiling vent a few inches, check that all vents are open (we had 2 clogged ones on a brand-new rig), and consider having one or both A/C fans on full-time.
It's certainly true that dual unit rigs in your size do have some difficulty in hot temps - you're description of the temp difference still makes me wonder about the dealer's assurance.

flaggship1 · 08-21-2016, 06:42 PM

Try pulling and cleaning the filters and making sure any nuts or screws you see that hold the unit to the ceiling are tight.

kwilkins · 08-21-2016, 06:51 PM

Quote:

Originally Posted by Floridakamper

It sounds like the same cooling I'm getting on a one week old Suncruiser 38Q. 92 degrees outside and 85 inside. Two 13.5 heat pumps on the roof. My trade, a Newmar had no problem cooling a similar size coach. The dealer said the AC's are working properly.

Were your heat pumps running continuously and the temp inside was 85? How humid is it where you are?

It seems madness to me that these new RV's can not keep cool inside.

kwilkins · 08-21-2016, 06:53 PM

Quote:

Originally Posted by Lv2Roam2

Bob
Certainly appreciate what your dealer says, but - try putting a thermometer of some sort up against one of the main vents (tape it in place)...if you don't get a reading of ~ 20 degrees less than the outdoor ambient temp you should talk with the dealer again. You should also open a ceiling vent a few inches, check that all vents are open (we had 2 clogged ones on a brand-new rig), and consider having one or both A/C fans on full-time.
It's certainly true that dual unit rigs in your size do have some difficulty in hot temps - you're description of the temp difference still makes me wonder about the dealer's assurance.

Bob - What would opening a ceiling vent a few inches accomplish. It would seen that would just let any cold air inside escape.

What am I missing?

Floridakamper · 08-21-2016, 06:54 PM

It sounds like kwilkens and I both have a problem. I'm not accepting the dealer's explanation that all is well. I have a number of other issues and one that I'm hoping will get fixed tomorrow. We have to be in the northeast here pretty quick for a month or so. I'm counting on Winnebago to somehow help me solve this and I intend to get it solved. I've checked the intake temps at the hottest part of the day and the discharge. I'm getting about a 10 degree difference. Again the dealer told me that is within spec.

Floridakamper · 08-21-2016, 06:56 PM

Quote:

Originally Posted by kwilkins

Were your heat pumps running continuously and the temp inside was 85? How humid is it where you are?

They both ran continuously. Right now in the evening, everything is fine.

kwilkins · 08-21-2016, 07:48 PM

Quote:

Originally Posted by Floridakamper

They both ran continuously. Right now in the evening, everything is fine.

We have had the same experience today. About an hour or so after the sun went down the RV started to cool down.

Please let me know what Winnebago and/or your dealer says. This is our first day of vacation and the weather is going to be hot the rest of the week.

Lv2Roam2 · 08-21-2016, 08:02 PM

Our coaches are essentially sealed metal boxes...at times the rate of heat gain exceeds the ~ 20 degrees max cooling effort available...opening a ceiling vent helps exhaust the warmest air at the ceiling and reduce some of the load on the A/Cs...

In the heat of the day deploying the awnings and closing all shades can also help...

grtharris · 08-21-2016, 08:18 PM

kwilkins, check the chill grill unit to make sure the return air and cool air are not mixing in the grill unit.

SuperGewl · 08-21-2016, 10:14 PM

Do you have all the window shades down and the front shades down for room blackout not just darkening? If not pull them both down fully. Check the air flow from each vent to see if you are actually getting any air out. Don't wait until the MH gets hot to attempt to cool it down, set the temperature at let's say 70 or colder before sunrise and let them get to work early. Keep all the shades down. Make sure fan is on AUTO and control is set to AC.
I've had no issues with mine keeping the MH down to 65 in the hottest of weather.

Floridakamper · 08-22-2016, 05:12 AM

Quote:

Originally Posted by SuperGewl

Do you have all the window shades down and the front shades down for room blackout not just darkening?

I do and the big awning and door awning. On the front AC I get a 20+ degree difference early in the day and late in the day. Between about 3 p.m. and 7 p.m. I get a 10 degree difference. The back AC has good cold air discharge all day but in the hottest part of the day that area gets up to 78 or 79 degrees. The 85 degrees is the temp we can't live with.

Hikerdogs · 08-22-2016, 07:12 AM

Quote:

Originally Posted by kwilkins

2017 Sunova 36z with 2 heat pumps. This morning the AC's (both set at 70) started running non stop when it was 77 degrees outside. The temperature in the RV keep rising throughout the day; with both units continually running. The high today was 86 (Cape Hatteras, NC) and inside the RV it is still 82 degrees.

There is "coldish" air blowing through all the roof vents. I don't know if it is not as cold as it should be. We traded in a 2010 Sunstar that also had 2 heat pumps that kept the RV cool in weather like this, and even hotter. The Sonova is 4 feet longer and much bigger inside with 3 slides.

Does this sound normal to you, or do you think we have a problem?

Thanks for any advice on this.

Ken

The suggestion of cleaning the filters has already been mentioned. If you haven't done it I would also suggest it as a place to start. They're just a foam disk behind each of the air intake ports. Just pop off the grill and take the disk off the back. Wash them in soapy water, rinse them off and let them dry a few minutes before reinstalling them.

Unlike the old basement system with a large furnace type filter these need to be cleaned on a regular basis. It doesn't take much dust, pollen, dog hair or anything else to lessen the air flow through the system.

Also if you're able I would go up on the roof and check for debris dust and dirt in the condenser coils. You'll have to remove the shroud. It is held in place by 4 machine screws with torx drive heads (I don't remember the size).

Here's a link to what the unit looks like with the shroud removed:
https://www.google.com/search?q=Cole...qD4-XSSIOHM%3A

I would also remove the second shroud on the right and look at the evaporator core. This one is held in place by 4 machine screws with phillips head drives. You might have a problem with this core freezing up. There should be a probe stuck in the fins. It's supposed to detect frost and cycle the compressor off long enough for the frost to dissipate. If it's not correctly placed or has come out of the cooling fins the compressor will keep running and the coils will freeze over. If this happens little or no cool air will enter the passenger compartment.

You may have to run the unit a little while with both shrouds removed to see if the evaporator will freeze up. It doesn't take long for the frost to dissipate once the compressor shuts down so it may have already dissipated by the time you get the shroud removed. If it does start to freeze you'll see frost form on the fins. Note where it starts to form then shut the system down and move the probe to that area of the condenser.

Floridakamper · 08-22-2016, 07:27 AM

Quote:

Originally Posted by Hikerdogs

I would also remove the second shroud on the right and look at the evaporator core. This one is held in place by 4 machine screws with phillips head drives. You might have a problem with this core freezing up. There should be a probe stuck in the fins. It's supposed to detect frost and cycle the compressor off long enough for the frost to dissipate. If it's not correctly placed or has come out of the cooling fins the compressor will keep running and the coils will freeze over. If this happens little or no cool air will enter the passenger compartment.

kwilkins, Hikerdogs brings up something you ought to check and may be at the root of our problems. When they checked my AC at the dealership, they said that it was iced up. They told me they moved the probe and that should take care of that issue. My AC condensate does not dump on the roof. There is some kind of a drain hose that takes the condensate to discharge under the chassis. I see it discharging at the rear of the MH. The tech also said something about a pump that he did something with. I didn't understand enough to ask an intelligent question and took him at his word that all would be well. (Yeah, I guess I'm gullible). Now, forward of the entry door I occasionally see condensate dripping down the side of the motorhome. With these issues, I'd really like to have the front AC upgraded to a 15K heat pump if they make such an animal. On the Newmar forum I've read that Dometic Penguins were no longer available in the 15K heat pump variety because of a federal change in type of freon and the new stuff is not as efficient as the old stuff. But I not know what I talk of!!

Hikerdogs · 08-22-2016, 08:00 AM

Quote:

Originally Posted by Floridakamper

kwilkins, Hikerdogs brings up something you ought to check and may be at the root of our problems. When they checked my AC at the dealership, they said that it was iced up. They told me they moved the probe and that should take care of that issue. My AC condensate does not dump on the roof. There is some kind of a drain hose that takes the condensate to discharge under the chassis. I see it discharging at the rear of the MH. The tech also said something about a pump that he did something with. I didn't understand enough to ask an intelligent question and took him at his word that all would be well. (Yeah, I guess I'm gullible). Now, forward of the entry door I occasionally see condensate dripping down the side of the motorhome. With these issues, I'd really like to have the front AC upgraded to a 15K heat pump if they make such an animal. On the Newmar forum I've read that Dometic Penguins were no longer available in the 15K heat pump variety because of a federal change in type of freon and the new stuff is not as efficient as the old stuff. But I not know what I talk of!!

It sounds like Newmar uses a condensate discharge system similar to the one Winnebago uses. On our Mach 8 AC units the evaporator core sits in a tray. The condensate drips off the coils and into the tray. When the tray fills sufficiently a small pump in the tray routs the condensate through a tube and it exits to the ground between the back panel and the bedroom wall of the coach. The pump has a small float to start and stop the pump. It's possible the tech changed the float level. If he/she got it too high the tray may overflow before the pump drains it if the coach isn't perfectly level.

lass · 08-22-2016, 09:37 AM

The Dometic Penguin II 15K H.P. Unit is now advertised as High Capacity and has a rating of 14.4K rather than the original 15K.

Part number is 651816.

Floridakamper · 08-22-2016, 09:48 AM

Hiker dogs, my current MH is a 2016 Suncruiser 38Q

cdrprn · 08-22-2016, 10:08 AM

We have a 2014 Itasca Suncruiser 32H and live in N. AZ where temps reach the 108+ range in summer. Our two heat pumps running on high cool can only ever cool the coach to 82. We added window awnings and the rolled foil over the windshield and front side windows to help keep the sun blocked with slight improvement. Our exterior colors are silver tones. Your coach is bigger than ours so your units might be functioning normally and are too "energy efficient" to cool any more. I would have them checked by a regular AC repair shop. We've had some bad results from dealerships who say everything's fine when it isn't especially under warranty. Contact Winnebago, they are are easy to deal with. By the way when it's hot, our Norcold refrigerator sometimes quits so we have to always travel with at least 1 really big ice chest. BOL in getting your units functioning to your satisfaction.