Increase ac vent air flow by 75%

[greenliner]

" Michael, Nigel just added two pages to the A/C mod, it takes a full case (24) of beer for a Brit to get the job done ".

It might take a 24 pack if it was American Water Beer - but a 6 pack of Boddingtons from UK would do a better job!!!!!

[mg0427]

Worked great for me. But cost more money then I wanted, it get so cold in the bedroom, the boss lady had to get a new heavier comforter, and matching sheets to go with it, she said "it was to much cold air blowing on her". I loved that statement.
It was only 105 outside and a nice 72 inside, I now don't need to put my beer in the fridge, I can just turn the AC down.

Michael

[Nigels]

6 Boddingtons, Nah! Just one pint of "Theakstons Old Peculiar" would have done the job

[Gduck24]

My ac has froze up twice. Cause appears to be poor airflow. I'm not happy with the air through vents. I'm going to try this mod when I get home. Hyperlink 19hfs with 15k but upgraded. Have any of you had an issue with freezing. This should help that right?

[Herk7769]

Originally Posted by Gduck24

My ac has froze up twice. Cause appears to be poor airflow. I'm not happy with the air through vents. I'm going to try this mod when I get home. Hyperlink 19hfs with 15k but upgraded. Have any of you had an issue with freezing. This should help that right?

Humidity in the camper and setting the thermostat too low for the humidity causes icing of the coils.

The compressor MUST cycle off and on to remove the humidity from your camper.

Never set the thermostat LESS than 10 degrees below outside air temperature in high humidity conditions until the humidity in the camper is removed; then you can lower it more in 10 degree steps.

The compressor needs to shut off so the frost on the coils can melt. If it does not, the frost will get thicker and thicker until it blocks your air flow and becomes a block of ice.

[Gduck24]

Originally Posted by Herk7769

Humidity in the camper and setting the thermostat too low for the humidity causes icing of the coils.



The compressor MUST cycle off and on to remove the humidity from your camper.



Never set the thermostat LESS than 10 degrees below outside air temperature in high humidity conditions until the humidity in the camper is removed; then you can lower it more in 10 degree steps.



The compressor needs to shut off so the frost on the coils can melt. If it does not, the frost will get thicker and thicker until it blocks your air flow and becomes a block of ice.

That makes sense. I thought the ac had a freeze sensor that would turn the compressor of to avoid that?

[Herk7769]

Originally Posted by Gduck24

That makes sense. I thought the ac had a freeze sensor that would turn the compressor of to avoid that?

Assuming the sensor is still in place (they have fallen out during installs or travels), it will shut off the compressor to protect itself. At that point you will be without AC until the ice that triggered the shutdown melts and the compressor can start up again. If the condition that caused it to ice up has not been resolved, it will just ice up again.

Better to prevent the problem in the first place.

[SlowrideHD]

Originally Posted by Herk7769

Humidity in the camper and setting the thermostat too low for the humidity causes icing of the coils.

The compressor MUST cycle off and on to remove the humidity from your camper.


The compressor needs to shut off so the frost on the coils can melt. If it does not, the frost will get thicker and thicker until it blocks your air flow and becomes a block of ice.

No, actually that is not correct. A properly sized unit with the correct airflow should only sweat the cooling coil and would not be frosting up. That's why condensate is continually running off the roof drain from a running air conditioner .

[Herk7769]

Originally Posted by SlowrideHD

No, actually that is not correct. A properly sized unit with the correct airflow should only sweat the cooling coil and would not be frosting up. That's why condensate is continually running off the roof drain from a running air conditioner .

While that may be true for home units, our one size fits all RV units can be overwhelmed in high humidity conditions.

[SlowrideHD]

Originally Posted by Herk7769

While that may be true for home units, our one size fits all RV units can be overwhelmed in high humidity conditions.

There is no "may be true" about it. It is a fact. An air conditioner does NOT have to cycle on and off to remove moisture (humidity) from the air being conditioned. If your cooling coil is freezing up, there are two possible universal problems, incorrect refrigerant charge or insufficient or restricted airflow across the cooling coil. A correctly sized and operating air conditioner is designed to sweat the cooling coil and drain the condensate off in continuous use.

[Gduck24]

I figured it was airflow. Pulled down the cover and there's basically no separation from return to output side. Literally a gaping hole above and in between. Also holes to ductwork we not as open as they could be. Lastly, there's a duct loop around the back of my camper. Why would they do this? I have 2 vents in back and 2 in front. Shouldn't the duct go straight to the vent and stop? I've never seen a loop in duct in all my life on residential or commercial.

See picture. Red highlight is duct loop. Can I block the loop and around my last vent to get some more airflow out? Like I get at a point pressure builds and it gets out vents but that's only with an end of a duct, not a loop? Send like if I blocked it off it would be less volume to fill and higher pressure out. It's probably double the volume to fill, so wouldn't that mean less air out? At a minimum I'm going to fix separation, smooth and enlarge holes to ductwork and potentially make a sweep to both ducts and block the dump of so I can use duct only. Dump is only good for cooling right in the middle of the trailer. No air gets to beds when using just the dump. Air through vents now sucks but I can clearly see why.

Would the gaping hole between cause an issue for freezing? I mean my brain says I'm putting super cool air right back in and my airflow out is really poor and turbulent so obviously losing major efficiency and spinning back on itself.

[Gduck24]

Update. Finished fixing and decided to just put things back together the way they were. Figured somebody smarter than me designed it, but somebody way dumber installed it. Pretty substantial air gains in the front bed vent. Ok gains in the back. I think based on this I will put the sweep in and try to increase duct flow and seal the air dump. The only thing I can think of on the loop is the engineers wanted to reduce flow to the back and have more at the front? Like to balance it a little? Going to experiment tomorrow with blocking duct loop. Hopefully someone can tell me if this is a bad idea.

Next - if someone can tell me how to get inside temp on the dometic thermostat while it's on cool and how to get my fridge to start cooking the first try without cycling the on of button or wiggling the temp sensor inside I'll be golden.

I think you can tell before and after pics. Sorry for resurrecting and diverting this thread. [emoji23]

[samTummo]

Only comment I have is, the only person who mentioned (he didn’t even mention it) but I saw it in his pictures. Metal tape covers turbulent causing areas very well. When I inspected mine I found the installer did an excellent job of covering the entire insides of the air transfer area with the metal tape. He must have been fired by FW for taking so much care and time in the area.

SamTummo

[str8t six]

Looks way better!