13,5K BTU vs. 15K BTU?

We replaced both of ours. 15k for main unit and 13.5 for rear and bathroom unit. I think the price difference was around $100 between the two.

Thomas Schwaiger wrote:
Hello All,
Haven't been on here for a while :h

We are due to replace both our air conditioners (they keep freezing up), but I'm wondering if it's worth the money going with 15 Btu units vs. 13.5? Price difference is about $300-400 each.
Any thoughts?

Thanks,
Thomas

YES!!!

We went through this last year. The old 13.5Ks were loud and never seemed to keep up. We bought a new 15K Penguin (part # 651816CXX1CO) and the board so we could use our old T-Stat (part # 3313107.107).

The new one is whisper quiet and keeps the camper as cold as we want it to be. We were camping this past weekend in 95F weather with 95% humidity with 30 amp service. The one 15K kept the entire camper cool and comfortable. Honestly the new AC is one of the best upgrades we've ever done on any RV.

1. Newmar units from 2001 have the 5 button Dometic CCC tstat control system. IF INSTALLED CORRECTLY, The AC units CANNOT freeze up. Regardless of any parameters than could cause freeze up.
2. WHY? Because all Newmar's from 2001 that have the Dometic 5 button system have FREEZE control Thermisters in the Evap coil, that will shut the compressor OFF when any freezing temps happen. Now, if you are experiencing Freeze up on BOTH AC units, replacing the upper units will NOT fix your problem. You have an operational control problem, not a Roof AC unit problem. Find and fix the operational control problem.
3. IF you are replacing the upper units because somebody told you that your freeze up is caused by a low charged AC unit, FIND ANOTHER SERVICE TECH, THEY DON'T KNOW WHAT THEY ARE DOING.
4. Yes, it is better to do with 15k units and make them Heat Pumps.
5. Now, you may have a problem replacing the top units. Usually MADP Newmar's had PENGUIN model low profile units. If so and you are replacing with Penguin's, you will need to replace the inside wall Tstat with a 10 button Dometic CCC. Because Penguin units come with the Upper Control Boards already installed and those boards will not communicate with your old 5 button CCC control.
6. Also, the roof cut out for the older Dometic AC units may not fit the newer Dometic AC units and the roof top duct hole for the Cold air exhaust may have to be modified to fit the AC units. Doug

Another thought....if the problem is that your A/C units are freezing up, the above suggestions are very valid...cleaning, sealing, etc. But, you might also have a misplaced or bad freeze sensor. My 15K unit on the front kept freezing up and what I found was that the freeze sensor had fallen off the coil. After finding that last year, I put it back into place and resealed all the inside of the unit where the cold air was getting back into the air flow across the coils..... And, as of this morning at 80 degrees outside with about 85% humidity, (so thick you can cut the air with a knife)... it was a very comfy 70 degrees inside!

Just replaced mine last week with Penquin 15k with heat pumps and new thermostate
Very easy to do. I backed my rv next to my deck to get them on the roof and threw the old ones off.

In my opinion Well.
I just read where one foreign country scored a record high. I did the metric to USA translation and it was 125 Degrees.. Your water heater is 120 folks

When I was stuck in GA a few years ago every day for two weeks the news weatherman was announcing "New record of consecutive days over 90"

We now have 80+ in ankorage alaska (highest temp ever recorded)

And the evidence of Global warming (It's getting hotter out there folks) is like the brick wall that was behind me when the bullies lowered their heads and charged like enraged bulls.. Hard to ignore (me I got outta their way and let the wall take the hit) (hey their plan was to cause someone pain 300% successful they were as there were 3 of 'em.. Mine was to avoid pain and I was only 100% successful).

So I'd go with the 15Ks

IN fact... I did.

The larger BTU units don't seem to work as hard to get up and keep the selected temps.

Freezing up possibly means you are operating on low setting in high humidity...plus you air return is picking up the already cooled air.
Coleman was at a rally in Oklahoma. We had another issue at the time: a fan slid down the shaft and bound up into the pan. However we as many have experienced over the years freezing up on low setting in high humidity. The examined all the vents inside and found the factory simply stuck pieces of aluminized fiberglass board around the air intake and outflow. A large part of the cooled air was going right back into the intake because of several gaps between the pieces. Some gaps were especially large. They explained it can cause freeze up many times. They used a lot of aluminized duct tape an sealed all the gaps in all the vents, five, and the coach was like a meat locker, hen before it struggled a lot lot more to keep up wit 100degree temps.
So I would do a service of cleaning the coils topside, not called for by your description but might as well,and clean inside as restricted airflow can cause freeze up and examine the duct work in the vents.
Also we have read here of even more extensive gaps and leaks in the duct work in the ceiling.
Maybe this will fix your problem and save enough money for a new motorcycle.
If you still nee to spend money, by all means get the 15,000btu unit.
Also I have read and someone here will know of units with 20,000 btu equivalent units but it has been a while. And keep those little intake filters clean and replaced. Restricted air flow from dirty cloggged filters can cause freeze up too.
Let us know if this makes any difference or you still need to replace the units.
If you cook such as deep fry inside without the vent above,stove on or even with it on you might/will find the filter clogged with dirt and grease that is nigh impossible to wash out. The fins in the a/c may need cleaned from this too.
I don't know why they haven't designed a better filtration system with replaceable high efficiency filters, that you don't have to take the intake down with screws. with a simple flow restriction alarm so it will get changed when needed.

Sounds like you have a air flow issue, with freezing up. Motor or dirty coil.

i vote for 15k.