15K Dometic Heat Pump

mikey · 07-17-2017, 08:13 PM

This thing is worthless in the South. Why not ask a potential owner where they spend most of their camping days. The answer to that question should determine whether a unit gets a heat pump or pure
A/C unit on a coach they will pay for and operate for many many seasons. Think of the savings in warranty calls when a heat pump unit fails to cool in places like Airzona, Texas, Florida or about anyplace in the south!

Witch Doctor · 07-17-2017, 08:23 PM

It has nothing to do being a heat pump. When on a/c it is the same as a regular a/c unit, to just have a different problem

zuckerburg · 07-18-2017, 02:14 PM

Quote:

Originally Posted by mikey

This thing is worthless in the South. Why not ask a potential owner where they spend most of their camping days. The answer to that question should determine whether a unit gets a heat pump or pure
A/C unit on a coach they will pay for and operate for many many seasons. Think of the savings in warranty calls when a heat pump unit fails to cool in places like Airzona, Texas, Florida or about anyplace in the south!

Your problem is nor the A/C as long as it functions as it is supposed to.
Do you have a front OUTSIDE windshield shader? Awnings on the side windows help. I have sunscreen material on the slide windows that stay on all the time. I have two 13500 A/C's and can cool it nicely in 95degree Florida humidity.

Subsailor · 07-18-2017, 02:47 PM

Hello Mikey. I have the 15K Dometic heat pump A/C on the front end of my coach and it seems to work fine even in the 95 plus heat. What is yours not doing? Glenn

zuckerburg · 07-18-2017, 06:07 PM

What you need is a probe thermometer. Take the temperature of the air in the vents. That will tell you how well the A/C is working.

Oscarvan · 07-19-2017, 01:44 AM

Yup. The AC part of a heat pump is the exact same thing as a pure AC.

The heat pump part comes in where you, essentially, reverse the thing and start cooling the outside dumping warm(er) air inside.

Sounds like yours may not be working properly.

That said, when the mercury gets in the high 90's it becomes a chore to cool these rolling ovens. Covering vents, shower sky light, and especially the cockpit green house makes a big difference.

nicholsm4 · 07-19-2017, 12:59 PM

In the housing industry there is a requirement to calculate heat load to determine cooling/heating minimum requirements. With RV's there is not the same robust analysis/requirement to protect the consumer. My TT has a 13.5k unit which is fine for a 20' TT but mine being close to 30' with 3 slides, there is no way this unit would ever cool sufficiently in 95 plus degree weather we have.

chief5631 · 07-19-2017, 01:09 PM

I've been in Texas and Arkansas in the 100-108 degree real feel range the past couple weeks and if you can get in the shade, a/c will make cool happen but if you're in the direct sun, no matter what you do...a/c will not be able to keep up.

conceptumator · 07-19-2017, 01:26 PM

We have the Dimetic 15K HP up front and a 13.5K AC in the rear and it cools great. July and August in Texas did require us to get a $15 reflective windshield screen since we were pointing westward in the 105F+ temps. In Florida we have no issues at all.

Walholler · 07-19-2017, 03:13 PM

Those Dometic 15K units are not heat pumps, what they are is an air conditioner with an electrical heating element installed in the air outflow area of the AC unit. When heat is selected, the cooling stays off and the heating element comes on, glowing red hot and the fan blows air across it and you have heat. A very small amount, but heat. We have a 32 ft. 5th wheel with two slides, found out real fast that one 15K unit cannot cool this baby in direct sunlight here in the deep south, but two 15K units can. Installed our second unit this spring without the heating element.

conceptumator · 07-19-2017, 04:01 PM

Quote:

Originally Posted by Walholler

Those Dometic 15K units are not heat pumps, what they are is an air conditioner with an electrical heating element installed in the air outflow area of the AC unit. When heat is selected, the cooling stays off and the heating element comes on, glowing red hot and the fan blows air across it and you have heat. A very small amount, but heat. We have a 32 ft. 5th wheel with two slides, found out real fast that one 15K unit cannot cool this baby in direct sunlight here in the deep south, but two 15K units can. Installed our second unit this spring without the heating element.

Uh....no. They are true heat pumps" not with a heating coil. Check the Dometic specs and/or look at one. There are units with the electric heating coil, but there are heat pumps, too.

RamblerGuy · 07-19-2017, 04:47 PM

Full body paint contributes a lot to the heat load. On our 32 foot Sunseeker with standard white paint and a few decals, if I put my hand on the dark decals, they are hot. The white paint will be much cooler. The hotter the outside skin, the more heat is conducted into the coach and the harder the A/C has to work.

It would be helpful if you post the temperature of the air going into the unit's return grille and the temperature of the air coming out of the vents. By comparing it to the temperature drop of other units that are working fine, you can tell if your unit is bad or if the heat load is just too much.

Subsailor · 07-19-2017, 05:23 PM

Quote:

Originally Posted by conceptumator

Uh....no. They are true heat pumps" not with a heating coil. Check the Dometic specs and/or look at one. There are units with the electric heating coil, but there are heat pumps, too.

Agreed. I just researched, purchased and installed one. There are two different kinds, heat pumps and those with "heat strips". -Glenn

chief5631 · 07-19-2017, 07:46 PM

I take it if I have a 15k dometic on a 2018 coachmen concord with 30 amp service I cannot install another ac?

zuckerburg · 07-19-2017, 07:49 PM

You would not be able to run them at the same time. A work around would be to wire the second to a separate direct power cord and pull it into the 110 at the post

chief5631 · 07-19-2017, 07:59 PM

so it can more than likely go where my DISH King satellite is especially cuz the DISH never comes in? and can a single additional 15k ac unit run off just household ac?

chief5631 · 07-19-2017, 08:08 PM

or would it help if I installed a higher BTU in place of the 15K? It really only gets a bit hot when in direct sunlight and its near 95-100 like it is every day where I live

conceptumator · 07-19-2017, 09:47 PM

Quote:

Originally Posted by chief5631

or would it help if I installed a higher BTU in place of the 15K? It really only gets a bit hot when in direct sunlight and its near 95-100 like it is every day where I live

Not sure, but I don't think anyone makes a unit larger than 15K. So far as mounting a second unit, you would need to install it somewhere that you already have a standard 14" x 14" roof vent, then route power (120v) to that opening as well as thermostat wiring. As stated above, you would want to feed that power wiring from outside so you could feed it directly from the 110v 20A receptacle at the pedestal.

Oscarvan · 07-20-2017, 12:32 PM

Why wouldn't you be able to wire a second unit into the coach system? Aren't we talking a 50A electrical supply here?

Edit.... just saw that this is not a Berkshire on the Berkshire page.

No, you can't run 2 ac's on a 30A system. So yes, getting a second supply from the pedestal is a good answer.

Oscarvan · 07-20-2017, 12:33 PM

Quote:

Originally Posted by RamblerGuy

It would be helpful if you post the temperature of the air going into the unit's return grille and the temperature of the air coming out of the vents. By comparing it to the temperature drop of other units that are working fine, you can tell if your unit is bad or if the heat load is just too much.

This. The "Delta T" should be at least 10ºF, preferably more.

You may also like: