Heater-AC Fan

[1nshort]

It got cold first night in foothills of Virginia, go figure. Turned on heater in the dining area and the AC unit fans came on. Heater cycled off but AC unit Fans continued. Used heater from rear controller (bedroom) same story but with rear AC unit fans. Has anyone asked Coachmen about this? Is it normal? Seems like a very strange operational mode if this is normal. On a hot day AC runs, room reaches temperature that is set, compressor goes off but fan continues to run on AC. Coachmen really needs to work on a good Coach Operations manual to explain how everything functions. Hot water heater DSI fault kept illuminating. I found the detailed manual on-line and found several reasons...had to adjust the air mix tube, gas was pulsing. After the adjustment everything was smooth (combustion) and no more DSI faults. I will post download for the hot water heater and a really excellent troubleshooting site.

[mvpmich]

Sounds very strange. My Sportscoach has to thermostats, one in the bed room for rooftop unit only and one in the main area that runs furnace nc forward rooftop. Both ave auto or maul controls for fan only mode but nothing tied together like your situation. Maybe a crossed or missed wired stat?

[Scott Colegrove]

check your thermostat, if it is a dometic or like and you have the fan speed set on low or high and you run the heat the a/c fan will come on. If you set the fan speed to auto it will not do this.

[UT Cardinal]

Ran into the same issue with my Cardinal. I had to pull out the instructions for the thermostat and read. I found out that you had to "fan" function on the main living thermostat in "auto" mode to get the AC to shut off. (I also had the bed room thermostat shut off - not sure if this is important or not??) If you have the fan in "hi" or "lo" mode the AC runs to circulate the air in the coach. The problem I found was the air coming out of the ceiling vents was cold.

[go6car]

Originally Posted by Scott Colegrove

check your thermostat, if it is a dometic or like and you have the fan speed set on low or high and you run the heat the a/c fan will come on. If you set the fan speed to auto it will not do this.

This should do it. I actually like the consistent/ambient noise, so I have mine set to keep the fan on at all times, weather I have the heat or AC on.

On another note -- not sure if you have this or not -- It seems like my AC is not distributed evenly throughout the ceiling coach vents (some blow out a lot more air than others). Same with the floor registers for heat. We get a TON of heat in the small bathroom, though. When we purchased the coach, was told that Coachmen has a unique ducting system through the ceiling somehow and they wouldn't be able to alter this in any way without ripping the ceiling apart. Lovely.

[Roll]

Originally Posted by go6car

This should do it. I actually like the consistent/ambient noise, so I have mine set to keep the fan on at all times, weather I have the heat or AC on.

On another note -- not sure if you have this or not -- It seems like my AC is not distributed evenly throughout the ceiling coach vents (some blow out a lot more air than others). Same with the floor registers for heat. We get a TON of heat in the small bathroom, though. When we purchased the coach, was told that Coachmen has a unique ducting system through the ceiling somehow and they wouldn't be able to alter this in any way without ripping the ceiling apart. Lovely.

We had the AC continue to run after the furnace shut down too. Dealer figured it out and advised the fan setting to stop it. No problem since.

Agree that the AC vents in the ceiling do not distribute evenly but would add that this has not really been a problem for us. The good news is that that AC units are adequate even in very hot weather and will keep your coach cool for you.

The heating ductwork is another matter and we have the same issue. Heat pours out of the bathroom vent (no way to close it, did you notice that) and heat just trickles out of the bedroom vent. I took the bathroom vent off and covered the rear with metal tape, then cut a small hole in the tape about 1/2 inch by 1 1/4 inches to restrict the air flow into the bath and hopefull force more heat out in the bedroom. My solution was only about 40% effective. A little more heat in the bedroom now but mostly the extra air flow goes into the kitcheon and the living room, neither of those vents are adjustable either.

Roll

[1nshort]

Originally Posted by Roll

We had the AC continue to run after the furnace shut down too. Dealer figured it out and advised the fan setting to stop it. No problem since.

Agree that the AC vents in the ceiling do not distribute evenly but would add that this has not really been a problem for us. The good news is that that AC units are adequate even in very hot weather and will keep your coach cool for you.

The heating ductwork is another matter and we have the same issue. Heat pours out of the bathroom vent (no way to close it, did you notice that) and heat just trickles out of the bedroom vent. I took the bathroom vent off and covered the rear with metal tape, then cut a small hole in the tape about 1/2 inch by 1 1/4 inches to restrict the air flow into the bath and hopefull force more heat out in the bedroom. My solution was only about 40% effective. A little more heat in the bedroom now but mostly the extra air flow goes into the kitcheon and the living room, neither of those vents are adjustable either.

Roll

I will do some experiments that I will run on the AC ducting. I have a theory I want to try out. More later, if it pans out. I will try to chase down the uneven heat from bathroom/bedroom registers. If they are separate runs it might be a simple matter of switching the feeds at the furnace. Flow could be as simple as positoning at the heater of the duct feed in relation to its position with the fan. I think the heater fan is a squirel cage induction fan. If so the further you are away from the center, the weaker the flow, we'll see.

[go6car]

Has to be something like that since I have the exact experience Roll has as well (heat gushing out of bathroom; not as much in bedroom floor vents).

On extremely hot days, we definitely need to get that AC on EARLY to ensure we cool the coach down. From what I understand, this is just the nature of the beast for Class As in general.

Interestingly enough, when I asked about upgrading the ACs to larger units, was told that it wouldn't truly help cool the coach down any better. This weekend should be a good test - 95 degrees with increasing humidity. With no shade. Yowza! I picked up two fans last year in case we ever needed them to help the AC. They may make their debut in the rig this weekend!

[1nshort]

Originally Posted by go6car

Has to be something like that since I have the exact experience Roll has as well (heat gushing out of bathroom; not as much in bedroom floor vents).

On extremely hot days, we definitely need to get that AC on EARLY to ensure we cool the coach down. From what I understand, this is just the nature of the beast for Class As in general.

Interestingly enough, when I asked about upgrading the ACs to larger units, was told that it wouldn't truly help cool the coach down any better. This weekend should be a good test - 95 degrees with increasing humidity. With no shade. Yowza! I picked up two fans last year in case we ever needed them to help the AC. They may make their debut in the rig this weekend!

I checked into this also. Our units have 13.5K BTU's for output. The best that could be used in our amperage rating is a 15K BTU unit so that would be a net gain of 3K BTUs. Not much of a gain only 10%. Have thought about replacing them with a heatpump unit, then you would have heat and AC, have to check the amps though. If near the 13.5 or 15K BTUs then it would work.

[Roll]

If I may... give your ACs a chance. We camped last July in Texas; no shade and it was a heat wave down there at the time. Temps hit over a hundred in the afternoon and yet I was comfortable in the coach all day long. Granted, the ACs ran all day and only shut down for short periods of time before restarting but they got the job done.

I have no issue with the AC set up.

Unlike heating where I'm not certain the bedroom thermostat does anything, when cooling the coach, the bedroom thermostat does control the AC unit over the bedroom.

Regarding the ceiling venting. You will find out, if you experiment, that the ceiling ductwork for the front and rear ACs are connected and that the units operate independently from the thermostats. If the rear AC is on but the living area AC is off you will feel cool air coming from the AC vents in the kitchen. Likewise, if the living AC is on and the bedroom AC is off you will feel cool air coming from the bathroom ceiling vents. So it is one network of vents/ductwork with two ACs connected.

I fiddled with opening and closing vents in an attempt to exercise some control over cool air flow. It's a work in progress. But again, I kept the coach down to 69 degrees in very hot weather (we were there about 5 days). I was happy with the service from the ACs and you know me, I get picky. One qualification.... Cindy was working in Dallas at the time and gone most of the day so it was just me and Miss Vivian (K9). I did run the living room DVR and TV though and they generate quite of bit of heat.

Roll

[mvpmich]

Originally Posted by 1nshort

It got cold first night in foothills of Virginia, go figure. Turned on heater in the dining area and the AC unit fans came on. Heater cycled off but AC unit Fans continued. Used heater from rear controller (bedroom) same story but with rear AC unit fans. Has anyone asked Coachmen about this? Is it normal? Seems like a very strange operational mode if this is normal. On a hot day AC runs, room reaches temperature that is set, compressor goes off but fan continues to run on AC. Coachmen really needs to work on a good Coach Operations manual to explain how everything functions. Hot water heater DSI fault kept illuminating. I found the detailed manual on-line and found several reasons...had to adjust the air mix tube, gas was pulsing. After the adjustment everything was smooth (combustion) and no more DSI faults. I will post download for the hot water heater and a really excellent troubleshooting site.

Do you have an on-demand wh or standard gas-electric unit? I'm having a difficult time getting our unit to operate efficiently.

[1nshort]

Originally Posted by mvpmich

Do you have an on-demand wh or standard gas-electric unit? I'm having a difficult time getting our unit to operate efficiently.

I have a gas/electric with electronic ignition. if you have the same, check a few settings that are critical to an efficient burn. 1. check allignment of the gas valve in relation to the air mix tube, it should be centered. 2. make sure that the air mix tube is 1/4 open, loosen securing screw and adjust (with pliers) hold it steady and tighten screw. 3. check the flat plate flame spreader and make sure it is perpandicular to the tube and centered. You know that the flame is burning efficiently if it is blue with very little to no yellow flickers and is not pulsing.
If you have a demand only the gpm (gallons per minute) on the water pump is critical. If you are on the park water flow is still critical and is directly related to pressure. Speaking about pressure, if you have a whole coach water filter, a clogged or wrong type filter will kill pressure. Buy only the type recommended in the manual. Do not believe the 'it's equivalent to your brand' statement. I did, it looked right, it fit, oh yeah, it cut my water pressure in 1/2.

[1nshort]

Originally Posted by Roll

If I may... give your ACs a chance. We camped last July in Texas; no shade and it was a heat wave down there at the time. Temps hit over a hundred in the afternoon and yet I was comfortable in the coach all day long. Granted, the ACs ran all day and only shut down for short periods of time before restarting but they got the job done.

I have no issue with the AC set up.

Unlike heating where I'm not certain the bedroom thermostat does anything, when cooling the coach, the bedroom thermostat does control the AC unit over the bedroom.

Regarding the ceiling venting. You will find out, if you experiment, that the ceiling ductwork for the front and rear ACs are connected and that the units operate independently from the thermostats. If the rear AC is on but the living area AC is off you will feel cool air coming from the AC vents in the kitchen. Likewise, if the living AC is on and the bedroom AC is off you will feel cool air coming from the bathroom ceiling vents. So it is one network of vents/ductwork with two ACs connected.

I fiddled with opening and closing vents in an attempt to exercise some control over cool air flow. It's a work in progress. But again, I kept the coach down to 69 degrees in very hot weather (we were there about 5 days). I was happy with the service from the ACs and you know me, I get picky. One qualification.... Cindy was working in Dallas at the time and gone most of the day so it was just me and Miss Vivian (K9). I did run the living room DVR and TV though and they generate quite of bit of heat.

Roll

Roll,
I don't have a problem with the AC units. I think the ducts are running in a split phase format. There are certaint duct outlets that are strong font and rear that are directly attahed to one unit, and the same is true for the other unit. The weak ones are getting air passing through the non opperating unit. Of course if both units are operating and you have weak flow out of a duct or two then my theory is garbage and Coachmen has poor ducting design.
My thinking about a AC/Heatpump replacement, is not wanting to use propane heater, when the heatpump side of the unit could heat the coach on shore power. They have units good down to 30-40 degrees. Dometic HP units, that only draw 15 amps and work with th existing controllers.
Just a thought.

[Roll]

Originally Posted by 1nshort

. I think the ducts are running in a split phase format. There are certaint duct outlets that are strong font and rear that are directly attahed to one unit, and the same is true for the other unit. The weak ones are getting air passing through the non opperating unit.

Well that's interesting but I'm not sure I agree. I do not run my ACs just to circulate air (fan mode). When the bed room unit is off I still get air in the bathroom (very close to the bedroom AC unit) from the front AC unit. That front AC also pushes air out to the kitchen and living room of course.

On the opposite side. The bedroom AC pushes air out to the bedroom, bathroom and to the kitchen when the front AC unit is off. The overlap is obvious. My ACs run independently by the way, based on where their thermostats are set. At times they are both running other times it is one or the other but not both. We do not always turn the bedroom AC on actually.

The simplest and most reasonable explanation is that they simply ran ductwork throughout the ceiling and connected two AC units, one to each end of the system.

As for volume, it is true in both the scenarios described that the closer the outlet to the AC unit that is running the stronger the push/higher the volume.

A test might be to close all the ceiling vents, turn on one AC unit and then open only one vent on the opposite side of the coach. I'll wager you'll get some cool air out of that vent.

Those are my observations anyway. By the way I only noticed this effect because we don't always run both units. I just happened to notice one day when the bedroom unit was running that I felt cool air coming out of a kitchen vent.

On the other hand, I could be completely wrong. Wouldn't be the first time.

Roll

[1nshort]

Update on candidate for Combo heat pump/AC rooftop unit:

http://www.dometic.com/b97fb7b3-584c...758792f7.fodoc

http://www.dometic.com/9ad940dc-efdc...af0d81ae.fodoc

http://www.dometic.com/1f24ead8-6316...87ce6bad.fodoc

These look like a drop-in. Most likely woud have to change out thermostat to the system management one that is available.

[Roll]

Originally Posted by 1nshort

Update on candidate for Combo heat pump/AC rooftop unit:

http://www.dometic.com/b97fb7b3-584c...758792f7.fodoc

http://www.dometic.com/9ad940dc-efdc...af0d81ae.fodoc

http://www.dometic.com/1f24ead8-6316...87ce6bad.fodoc

These look like a drop-in. Most likely woud have to change out thermostat to the system management one that is available.

I can appreciate that the heat pumps would be nice, especially when you consider how much propane you burn on a cold night. And since you plan to do some full timing, it makes sense.

Changing out those units will be a job though and I don't imagine they let them go for cheap.

It does appear they use the same wall controls we have; or they look the same anyway, may not be I suppose.

Roll