The first of several modifications to tailor our rig to exactly what we want.
Actually the original RV A/C unit plus a portable heat pump we're using as the additional A/C unit.
My wife vocally complains about the heat here in the desert southwest and wanted a cooler rig else we would not be traveling to hot areas. I wanted an easy solution so came up with this modification to our under-powered 5th wheel.
My method is not exactly pretty, but it required minimum work to get it operational. There are now two ways to connect the second A/C unit to the park power supply:
I left the original 30A circuit RV completely alone and added the second power inlet to serve a single new socket inside the rig (in the same area as the power inlets are located). That socket is protected with a 20A marine breaker, and I deliberately chose a round socket so the wife will always know that anything plugged into the round socket is on the new circuit.
We now plug the 12,500 BTU heat pump into that dedicated circuit, and have the vent for the portable unit ducted outside the window where the unit is located.
We tried it out on a run to Orifino Idaho on the Clearwater river where the temperature was 105 degrees. We were very comfortable in our newly equipped rig with both cooling units running.
The 30A inlet on the left had a 20A cord attached to run the second A/C if a proper 20A outlet is available on park power
We can also connect via a 50A cord split into two 30A inlets
Inside the rig the round socket is powered by the new feed, and is protected by a 20A marine breaker (on the left_
This is the 12,500 BTU heat pump that we are using as the second A/C
The heat pump is ducted out one of the windows in the slide
Actually the original RV A/C unit plus a portable heat pump we're using as the additional A/C unit.
My wife vocally complains about the heat here in the desert southwest and wanted a cooler rig else we would not be traveling to hot areas. I wanted an easy solution so came up with this modification to our under-powered 5th wheel.
My method is not exactly pretty, but it required minimum work to get it operational. There are now two ways to connect the second A/C unit to the park power supply:
- Using the existing 30A cable and a second 20A cable - I added an additional NEMA L5-30R power inlet. I understand this might not be usable in all parks because the 20A and 30A park sockets are wired on the same 3Aa source.
- Using a new 50A power cord and a "Y" splitter adapting the 50A cord to two 30A plugs, then to the rig
I left the original 30A circuit RV completely alone and added the second power inlet to serve a single new socket inside the rig (in the same area as the power inlets are located). That socket is protected with a 20A marine breaker, and I deliberately chose a round socket so the wife will always know that anything plugged into the round socket is on the new circuit.
We now plug the 12,500 BTU heat pump into that dedicated circuit, and have the vent for the portable unit ducted outside the window where the unit is located.
We tried it out on a run to Orifino Idaho on the Clearwater river where the temperature was 105 degrees. We were very comfortable in our newly equipped rig with both cooling units running.
The 30A inlet on the left had a 20A cord attached to run the second A/C if a proper 20A outlet is available on park power
We can also connect via a 50A cord split into two 30A inlets
Inside the rig the round socket is powered by the new feed, and is protected by a 20A marine breaker (on the left_
This is the 12,500 BTU heat pump that we are using as the second A/C
The heat pump is ducted out one of the windows in the slide
Just to spruce up the temperature control a bit more, I replaced the original analog thermostat with a residential Honeywell digital unit. It was basically plug and play once you get the wiring right - the whole project tool all of about 30 minutes. Note there are thin wires connected to sometimes different color thick wires. The thin wires are off the original thermostat and are the wires that you screw into the new thermostat.
The original Coleman Mach compared to the New digital on the right. The digital uses two AA batteries as the power source.
After removing the Coleman, these are the original six wires. The new digital does not have a hi/lo fan speed setting, so I did not use all the wires - only four, and capped off the gray and blue. The thin wires are the correct ones to use for the color coding
Here the wires are in place, and the rest tucked back into the wall. Red is the original 12V, yellow is the A/C, white is the furnace, and green is the high fan speed.
The finished install - works perfectly, keeps the temperature way better, and best of all, I need not futz around with those tiny micro control switches any more!
The original Coleman Mach compared to the New digital on the right. The digital uses two AA batteries as the power source.
After removing the Coleman, these are the original six wires. The new digital does not have a hi/lo fan speed setting, so I did not use all the wires - only four, and capped off the gray and blue. The thin wires are the correct ones to use for the color coding
Here the wires are in place, and the rest tucked back into the wall. Red is the original 12V, yellow is the A/C, white is the furnace, and green is the high fan speed.
The finished install - works perfectly, keeps the temperature way better, and best of all, I need not futz around with those tiny micro control switches any more!
The continuing saga - the A/C in my Rockwood Signature Ultralight has always had problems cooling the unit to the point where I thought that the A/C was broken or defective in some way. The air coming out of the ceiling registers was never more than barely cool, and the air flow very weak. I thought I needed a second A/C unit so made a modification to the electrical system to allow the addition of a heat pump.
The A/C unit has also dripped water out of from the inside cover and I thought it was some kind of condensation (wrong). I saw a post where someone added a marine observation port to allow dumping of the cold air directly into the rig, and also saw mention of sealing the duct work to prevent leaks, so I decided to remove the cover and see what I could do to implement some of these fixes. I was also perplexed as to why the A/C was dripping while it was turned off on a foggy night.
I was shocked to see that one bolt was backed out nearly 2 inches, and all were loose - this is why water was dripping. It was probably my bad not checking the bolts, but this dripping was occurring from day one so it could have been poor assembly.
Next, I looked for ducts, but found none. I ran my hand into two slit-like spaces leading into the roof space and concluded that this must be the "ducting" to the air outlets, and was correct. Evidently there are no ducts in my ceiling - the A/C air simply dumps right into the space between the roof and the ceiling (this explains why I felt air coming out of the light fixtures when the A/C is running). Sure there is 3/8 inch styrofoam on the interior of the ceiling and another layer on the inside of the roof, but really? ... using the entire roof as the air ducting system? No wonder the air flow was weak, and temperature was barely cool.
I read another post where someone measured the temperature of their roof to be 191 degrees on a sunny day. I cannot believe that a 3/8 inch layer of styrofoam will do much of anything to keep the ceiling space from becoming really hot and storing that energy in everything in the ceiling, like the light fixtures, structural supports, etc. In effect, the A/C had to cool all structural elements down before it much of anything to cool the rig.
It looks like this A/C unit was designed for a TT because there is a large grid where air is supposed to come out. Rockwood had covered this with a sheet metal plate which deflected the cold air into the slits leading to the ceiling space (see pics). They could then punch a hole anywhere in the ceiling to tap into the "duct" because essentially the entire ceiling is one big duct (talk about a waste of energy).
Because the ceiling air outlets are essentially only eye candy with little to no function, I took off the sheet metal in the A/C cover and was amazed at the difference. A huge volume of icy cold air now comes out of the unit, and in a test yesterday I was able to get the rig down to 65 degrees before the A/C automatically shut off. I've never been able to get the rig that cold under these weather conditions. Sure, I have lost air distribution through the ceiling, but I have gained more than enough cold air to make the rig comfortable.
The take home lesson - if you are having problems with your rig cooling, take off the A/C cover and see what surprises the manufacturer has in store for you. I've learned that my rig looks beautiful on the inside, but those looks come at the expense of function.
The yellow arrow points to one of the slit-like opening into the ceiling space
This is how I discovered that there are no ducts - I fed a tape measure into the slit and worked it back toward an air outlet - no obstructions of any kind and I could move the tape in all directions.
This shows the interior A/C cover where the air was supposed to come out in the original A/C design, and you can see black foam through the grid
This is the interior of the cover - you can see the sheet metal plate which I took off. The A/C unit now blows huge quantities of icy cold air - a gigantic contrast to the barely cool air that has always come out of the unit. I was more than willing to give up poor air distribution for cold air.
The A/C unit has also dripped water out of from the inside cover and I thought it was some kind of condensation (wrong). I saw a post where someone added a marine observation port to allow dumping of the cold air directly into the rig, and also saw mention of sealing the duct work to prevent leaks, so I decided to remove the cover and see what I could do to implement some of these fixes. I was also perplexed as to why the A/C was dripping while it was turned off on a foggy night.
I was shocked to see that one bolt was backed out nearly 2 inches, and all were loose - this is why water was dripping. It was probably my bad not checking the bolts, but this dripping was occurring from day one so it could have been poor assembly.
Next, I looked for ducts, but found none. I ran my hand into two slit-like spaces leading into the roof space and concluded that this must be the "ducting" to the air outlets, and was correct. Evidently there are no ducts in my ceiling - the A/C air simply dumps right into the space between the roof and the ceiling (this explains why I felt air coming out of the light fixtures when the A/C is running). Sure there is 3/8 inch styrofoam on the interior of the ceiling and another layer on the inside of the roof, but really? ... using the entire roof as the air ducting system? No wonder the air flow was weak, and temperature was barely cool.
I read another post where someone measured the temperature of their roof to be 191 degrees on a sunny day. I cannot believe that a 3/8 inch layer of styrofoam will do much of anything to keep the ceiling space from becoming really hot and storing that energy in everything in the ceiling, like the light fixtures, structural supports, etc. In effect, the A/C had to cool all structural elements down before it much of anything to cool the rig.
It looks like this A/C unit was designed for a TT because there is a large grid where air is supposed to come out. Rockwood had covered this with a sheet metal plate which deflected the cold air into the slits leading to the ceiling space (see pics). They could then punch a hole anywhere in the ceiling to tap into the "duct" because essentially the entire ceiling is one big duct (talk about a waste of energy).
Because the ceiling air outlets are essentially only eye candy with little to no function, I took off the sheet metal in the A/C cover and was amazed at the difference. A huge volume of icy cold air now comes out of the unit, and in a test yesterday I was able to get the rig down to 65 degrees before the A/C automatically shut off. I've never been able to get the rig that cold under these weather conditions. Sure, I have lost air distribution through the ceiling, but I have gained more than enough cold air to make the rig comfortable.
The take home lesson - if you are having problems with your rig cooling, take off the A/C cover and see what surprises the manufacturer has in store for you. I've learned that my rig looks beautiful on the inside, but those looks come at the expense of function.
The yellow arrow points to one of the slit-like opening into the ceiling space
This is how I discovered that there are no ducts - I fed a tape measure into the slit and worked it back toward an air outlet - no obstructions of any kind and I could move the tape in all directions.
This shows the interior A/C cover where the air was supposed to come out in the original A/C design, and you can see black foam through the grid
This is the interior of the cover - you can see the sheet metal plate which I took off. The A/C unit now blows huge quantities of icy cold air - a gigantic contrast to the barely cool air that has always come out of the unit. I was more than willing to give up poor air distribution for cold air.
Moderator edit to re-size pictures to forum limit of 640px maximum width.
TNGW1500SE wrote:
Better solution than most but I would still not want all those plugs in the rain. Everybody does it with 30 to 50's but they're not waterproof.
NOT EVERYBODY:W
That is easily solved if you make you're own dual 30A to 50A dogbone like I did for under $80
Of course my 60A system requires you to run 2 30A cords from the pedestal, but each is much easier to handle than a 50A and you only need to purchase one extra that could be used to extend your existing 30A in an emergency for an extended single 30A service.
Larry
