Another A/C Mod

[Garypowell]

I have progressively been trying to improve the performance of my A/C system in my 3010RE.

First, I did the “tim” method. Don’t think it helped much since it seemed to me the system was fairly well sealed and working OK. I did get a slight increase in airflow. I don’t really know how old this idea is and maybe there have been engineering/equipment changes since it came into being.

Then I put closable dampers in the bedroom. When we were not in the bedroom we could close these to push more air to the living area. I got some success with this but a lot of trouble always adjusting the dampers. And the bedroom was hotter too.

Then I noticed every time I pulled a light fixture down there was cold air coming out of the hole. So I put a block in the duct work after the last hole at both ends. This seemed to help a fair amount and I got a little more air flow.

Not exactly unhappy but I still wanted more air flow and also cut down on the run time of the units.

A week ago I had another idea.

I took a piece of what I call swimming noodles (cut to size) and blocked the common ducts that run between the bedroom and living space. As you know there are two duct runs on either side….so blocked them both. This effectively keeps the bedroom A/C cooling the bedroom and the main A/C cooling the living area of our Rig. I did finally put the bedroom duct block after the bathroom register. I had first tried to have the bathroom get its air from the main A/C but was not getting enough air. So the bathroom now gets its air from the bedroom A/C.

I immediately noticed more air flow and shorter run times. My bedroom A/C used to labor for hours until this idea struck me. While I initially liked the common ductwork in reality it actually siphons off air to the area whose thermostat is calling for cooling. Both units run independently as they each have a thermostat. But they run, I can actually feel the cool air, the temperature drops, and they shut off.

Granted during the real hot summertime both units are going to run a lot. But after a week of living with this mod I find the units run a lot less. Especially at night when the demand is down.

 

[Az_Ernie]

I have progressively been trying to improve the performance of my A/C system in my 3010RE.

First, I did the “tim” method. Don’t think it helped much since it seemed to me the system was fairly well sealed and working OK. I did get a slight increase in airflow. I don’t really know how old this idea is and maybe there have been engineering/equipment changes since it came into being.

Then I put closable dampers in the bedroom. When we were not in the bedroom we could close these to push more air to the living area. I got some success with this but a lot of trouble always adjusting the dampers. And the bedroom was hotter too.

Then I noticed every time I pulled a light fixture down there was cold air coming out of the hole. So I put a block in the duct work after the last hole at both ends. This seemed to help a fair amount and I got a little more air flow.

Not exactly unhappy but I still wanted more air flow and also cut down on the run time of the units.

A week ago I had another idea.

I took a piece of what I call swimming noodles (cut to size) and blocked the common ducts that run between the bedroom and living space. As you know there are two duct runs on either side….so blocked them both. This effectively keeps the bedroom A/C cooling the bedroom and the main A/C cooling the living area of our Rig. I did finally put the bedroom duct block after the bathroom register. I had first tried to have the bathroom get its air from the main A/C but was not getting enough air. So the bathroom now gets its air from the bedroom A/C.

I immediately noticed more air flow and shorter run times. My bedroom A/C used to labor for hours until this idea struck me. While I initially liked the common ductwork in reality it actually siphons off air to the area whose thermostat is calling for cooling. Both units run independently as they each have a thermostat. But they run, I can actually feel the cool air, the temperature drops, and they shut off.

Granted during the real hot summertime both units are going to run a lot. But after a week of living with this mod I find the units run a lot less. Especially at night when the demand is down.

Gary,
We own a 2015 3160EL Bighorn. Our bedroom has two A/C supply ducts and two return ducts. The most forward supply duct has great output and the rear duct has very poor airflow. Knowing that the bedroom and living quarters a/c's were inter connected, I pulled the rear supply duct vent down and blocked the duct going to the living quarters. The airflow to the rear duct in the bedroom improved dramatically. I did not disturb the return duct. Since you completed your mod almost a year ago, has the blocking of these ducts created any problems?

 

[Garypowell]

Ernie,

it it continued to work well until 2weeks ago when we started a 2 month trip. I had checked the a/c units before we left and while the main unit seemed "weak" it was cooling. The first day out it died.

I dont think there was any connection between the two but in fairness felt I should mention it. If anything both units ran less as they only had their area to cool which I found more efficient.

I had read that HL seemed to be using these split duct systems and think my idea was still valid and you are proving that.

But once the unit failed (reported in another recent post) I was forced to inter connect the ductwork again.

We are spending a month near Knoxville (Anchor Down) and I hope the bedroom a/c will continue to be sufficient. After a move it takes a while to cool the rig down but once cool the smaller unit has kept the place in the mid 70's. I plan on replacing the main unit but need to work through extended warranty stuff and if the work can be done where we will be sitting. I have considered canceling the policy and getting roughly $1,000 back and fixing the problem myself. Dometic has a newer design now and I have seen it on line for around $500.

I had another post that you might have missed where I blocked off the ends of the ductwork also. I changed out all of my lights to LED's and every time I would work with a fixture I would notice cold air coming out around it. My theory then became that the ends of the duct were not blocked off. So I put a block after the last return on each run......you might want to try that too.

 

[Az_Ernie]

Ernie,

it it continued to work well until 2weeks ago when we started a 2 month trip. I had checked the a/c units before we left and while the main unit seemed "weak" it was cooling. The first day out it died.

I dont think there was any connection between the two but in fairness felt I should mention it. If anything both units ran less as they only had their area to cool which I found more efficient.

I had read that HL seemed to be using these split duct systems and think my idea was still valid and you are proving that.

But once the unit failed (reported in another recent post) I was forced to inter connect the ductwork again.

We are spending a month near Knoxville (Anchor Down) and I hope the bedroom a/c will continue to be sufficient. After a move it takes a while to cool the rig down but once cool the smaller unit has kept the place in the mid 70's. I plan on replacing the main unit but need to work through extended warranty stuff and if the work can be done where we will be sitting. I have considered canceling the policy and getting roughly $1,000 back and fixing the problem myself. Dometic has a newer design now and I have seen it on line for around $500.

I had another post that you might have missed where I blocked off the ends of the ductwork also. I changed out all of my lights to LED's and every time I would work with a fixture I would notice cold air coming out around it. My theory then became that the ends of the duct were not blocked off. So I put a block after the last return on each run......you might want to try that too.

Thanks, Gary. I'm with you, I really don't think blocking the ducts contributed to your A/C malfunction. Maybe some of our forum A/C experts can chime in here and advise me not to, but until I'm convinced differently, I'm going to block our ducts and take your advice and block off the ends as well.

 

[Lou_and_Bette]

I was replacing my roof vent caps with the new Lippert 360 ones and noticed a fair amount of cold air coming up around the pipes where they came through the roof, so I used some of the old Dicor putty I removed to get old caps off and sealed around the tubing tightly...I think this will help hold the cold air in the coach.

 

[Toy1Ton]

I have the new whisper quite system in my 3760EL, with the bed room unit turned off shouldn't I feel some air flow from the living room ac in the bedroom?

 

[jmgratz]

I have the new whisper quite system in my 3760EL, with the bed room unit turned off shouldn't I feel some air flow from the living room ac in the bedroom?

Yes you should but it is not much

 

[Toy1Ton]

well I'm not getting anything