Seneca air conditioning

[ElBlondie]

We own a 2020 Seneca HJ. We are currently in Moab, Utah. The ambient temperature is 85 degrees and with both air conditioners going the coach is 76 with the thermostat set at 72. It got up to 81 in the coach yesterday when it was 102 outside. Is this normal or is the AC not functioning properly?

[SloPoke]

First - Welcome to the Seneca family....




In our Seneca, in direct sun beating on the side of the MH when it is 100F and above - our two 15,000 BTU AC units are barely able to keep it cooled down.

Things we do to help it keep cool:

* Put the awning out a little bit to shade the side of the Motorhome.
* Put insulating / reflective covers on the windshield and cab windows.
* Avoid leaving the entry door open as much as possible.

[EA37TS]

Welcome to. the forum.

You need to determine the delta T for the system. The delta T is determined by measuring the temperature of the air going into the cold air return and the measuring the temperature coming out one of the air vents. The difference between the 2 is the delta t. A correctly functioning system will have a delta t of 18 - 22 degrees.

Google HVAC Delta T and you can find more info than you want to know.

Also, there were some you tube videos out where some folks pulled the grate off their AC unit and found that the barrier between the cold air return and the AV vents was not adequate and their cold air was mixing with the returned warmer air before entering the AC duct work.

[ElBlondie]

Thanks for the replies. I’m going to test the t delta and otherwise implement the suggestions.

[SloPoke]

Originally Posted by ElBlondie

Thanks for the replies. I’m going to test the t delta and otherwise implement the suggestions.

Just to clarify my comments... I'm assuming that your AC units are properly installed and the baffles are placed correctly with proper ducting.

If you look at this from another perspective, Jayco puts 34,000 BTU's of heating into the motorhome. They put 30,000 BTU's of cooling in our 2015 Seneca, but the later models have only 28,500 BTU's of cooling and a darker outside paint colors.

We spend a lot of time in Moab, We try to get a spot where the cab faces east so the patio side of the motorhome is facing south and we can get shade on the sidewall with our Awning partially extended. Another reason for this alignment is because the overcab one-piece fiberglass unit over the cab has essentially no insulation in it, is painted the darkest color on our rig... and the afternoon sun will cook the insides of our Seneca on a hot afternoon.

[Robbbyr]

A barrier between the cab and the coach also helps reduce the heat load, even if you have cab window shields.

My wife repurposed our original beadspread as a divider. It is quilted and does a good job.

[SloPoke]

Originally Posted by Robbbyr

A barrier between the cab and the coach also helps reduce the heat load, even if you have cab window shields.

My wife repurposed our original beadspread as a divider. It is quilted and does a good job.

Robbbyr is right on this one! The cab of our Seneca is not insulated, and is a huge source of cold drafts in winter and sweltering heat in summer.

I have to say that in Winter, we switch how our preferences are... to make the passenger side of the motorhome facing south, so we can get what little winter sun there is to warm the motorhome side. The dark colors of our unit are sometimes too hot to touch in the winter sun... and always too hot to touch in the summer. I wished that Jayco made a lighter color scheme sometimes.