A/C question

[Roadtoaster]

Finally took the new toy out for the weekend. Had a great time and everything worked fine, with the possible exception of the A/C. Cooled fine but just didn't seem to remove the humidity from inside as well as I expected. A/C ran all afternoon and evening. No showers taken and we weren't in the trailer until 10:00 PM, meaning we weren't even breathing in there all afternoon and evening. Condensation dripped from the drain but still felt clammy inside. Trailer was level and parked in the shade. After I turned the unit off on Sunday there was a significant increase in the amount of water comming from the condensation drain.

Does this sound normal or should I be looking at the condensation pan to see if there is a blockage? Would a blockage result in increased humidity inside or just a leak? This is all new to me so any help would be appreciated.

Thanks

Greg

[Jim & Susan]

A buddy of mine who is an HVAC guy told me once that the way to remove humidity is have the unit run for long periods of time (as opposed to cooling to a certain temp and shutting off for long periods). Maybe you need to turn the thermostat down a little lower so that the "on" cycles are longer?

Jim

[dmreilly10000]

I think if the drain hose was plugged up, the water would drip out of the air conditioner and into the inside of the trailer.

See my latest problem at: http://www.airforums.com/forum...ard-23312.html

You could try shoving a piece of wire or something like it up the drain tube to unclog it. Dirt dobbers had plugged mine up.

To monitor my air conditioner, I went bought an indoor/outdoor electronic thermometer. I set it on the counter, place the outdoor probe into the cold air vent. That way I can see the temperature differential between the inside of the trailer and the cooled air comming out of the unit. It also has a relative humidity display so I can see if it is actually humid or just feels that way.

If it ran for hours on end, it should have removed a lot of water from the air. Is the unit getting cold enough to condense the water from the air?

Hope this helps.

[Roadtoaster]

Thanks for the replies. I have one of those indoor/outdoor thermometers so guess I'll put the outdoor unit buy the A/C, turn it down real cool, let her run and see what happens.

thanks

Greg

[jcanavera]

If you have an air conditioner that has a constant running fan, you will deal with humidity problems when temperatures are not terribly hot outside. It will be especially evident at night.

The problem is humidity is only being removed from the trailer when the compressor is running. Once the compressor turns off and if the fan continues to run, the moisture that is present on the inside coils will be reintroduced back into the inside air. In the case where it is not extremely hot, short run cycles of the compressor will not allow enough humidity extraction. Noting that you were in the shade probably gives me the impression that after the initial cool down, the compressor was probably cycling, with not much heat gain in the trailer. Especially since you weren't occupying the unit for long.

My Safari had a continuous run fan, where my Classic fan cycles on and off with the call for cooling. It makes a difference in the humidity and comfort levels.

Like Jim noted, you can turn down the thermostat which will force the compressor to run longer.

On new build Safari's you can ask for the Comfort Control thermostat which will allow your heating and cooling to be controlled by the wall thermostat. In this case the fan will cycle off and on. Silvertwinkie got that installed along with a bigger A/C unit when his 25' Safari was built.

Jack

[Roadtoaster]

Jack, what you say makes a lot of sense. I have discussed the thermostat issue with the manufacturer. Sounds like I can "upgrade" to the wall mounted unit but of course, everything comes with a price!! Also installing a
fantastic fan this weekend, maybe that will help as little as well.

Thanks for the input.

Greg

[jcanavera]

Originally Posted by ptrvr

Jack, what you say makes a lot of sense. I have discussed the thermostat issue with the manufacturer. Sounds like I can "upgrade" to the wall mounted unit but of course, everything comes with a price!! Also installing a
fantastic fan this weekend, maybe that will help as little as well.

Thanks for the input.

Greg

It's not quite as simple as upgrading the thermostat since your air conditioning controls are mounted on the air conditioner itself. The air conditioner on my Classic has no external controls and has internal circuity that runs to the thermostat. I know one person who did do this upgrade himself and it did require additional wire pulls and some other work on the air conditioner to control from a wall mounted thermostat.

That's why you really need to do this at trailer build time. I'm not sure if your dealer would tackle this kind of project....or if he does, how much it will set you back. If anything, you sort of do what we did when we had the Safari, and that is dialing down the thermostat when compressor run time dwindles. You pile lots of blankets on the bed and when you wake up in the morning you will have condensation on the outside of your windows!


Jack

[Roadtoaster]

Yes, it is complicated and includes buying a new "lower unit" (probably not the correct description). Piling on the blankets is good for me but not so good for my cold natured wife!!! Probably just need to camp more in the cooler months and keep her in sweaters.

Greg

[acrane]

Where is condensation pan so can check for blockage. Have water running down the side of my trainer from the ac.


Thanks

[Jim & Susan]

On mine, it's directly below the coils, it then drains to a tube that runs thru the roadside wall out thru the belly on to the ground.

[fastrob]

Hope this is not too far off topic but my wife hates a/c.
We need a de-humidifier.
A/c's act as de-humidifiers but cold, anyone use de-humidifiers?

R

[Roadtoaster]

When my a/c issues surfaced, I talked with a seemingly well informed hardware type at Home Depot about using a dehumidifier in mine. His comments were they work just like an a/c unit, except they dump the WARM dry air back in the trailer, meaning the a/c has to work harder to keep things cool. I'm so confused at this point I'm just sitting back and waiting for cooler weather as opposed to 95 degrees.

Greg

[fastrob]

Just read about air conditioners with dehumidifier options.
I believe the humidity is more uncomfortable than dry air at the same temp.
We breath and sweat out water.

R

[tpi]

I think Jack has hit the nail on the head with his short cycling theory. The compressor cycle is so short the condensate on the fins is simply blown back out into the room when the evaporator heats up during the compressor off cycle.

I'd check to see if the unit is cycling as he suggests. If it is, the thermostat solution to cut the fan is a good one. As a stopgap, try finding a sunnier site which would force more compressor run time. Or possibly running a low power electric heater to force the compressor to run more (if power is provided free).

I have the same continuous run fan in my 25' Safari, but in the low humidity desert southwest compressor run time is continuous during the day parked in the sun. Last week in Las Vegas the compressor didn't cycle from 9 AM to 8 PM.

[CanoeStream]

Originally Posted by fastrob

We need a de-humidifier. A/c's act as de-humidifiers but cold, anyone use de-humidifiers?

As the following reply suggests, a dehumidifier is a refrigeration unit that collects water that collects on a cooled coil -- just like moisture on the outside of a glass of iced tea. Mechanical inefficiency being what it is, the heat produced by the unit does become an issue. They will do very little for humidity levels inside if you have a window open, so maybe you could run it when not 'home' and turn it off when you're back at the trailer.

Morningtime moisture on windows? Even in cold weather I leave several windows unlatched at the opposite end of the trailer so that exhaled moisture has a way to get out.

[jcanavera]

Originally Posted by ptrvr

When my a/c issues surfaced, I talked with a seemingly well informed hardware type at Home Depot about using a dehumidifier in mine. His comments were they work just like an a/c unit, except they dump the WARM dry air back in the trailer, meaning the a/c has to work harder to keep things cool. I'm so confused at this point I'm just sitting back and waiting for cooler weather as opposed to 95 degrees.

Greg

That idea would work to control humidity. That person was correct to state that a dehumidifier is really an air conditioner unit but instead of the cold air being exhausted into the surrounding clime, the cold air is directed back to the rear coils which are hot, thusly being warmed back up. That's why the heat from these units is usually a lot less that what a typical air conditioner exhausts.

But I would differ as to the statement that the A/C unit would be working harder. As a matter of fact your air conditioner cycle time would be even less since the air would be drier and the dehumidifier only runs when humidity exceeds the setting on the controls. This is due to the fact that extracting moisture from the air has a negative effect on the cooling process.

An air conditioner has two jobs to do and if you minimize the humidity, you lessen the workload. As more humidity is extracted from the air, the cooling process is improved and very easily can overcome any small amount of additional heat load that the dehumidifier puts out.

If you have a humidistat in a hot high humidity room, you will see a marked reduction in the time frame in temperature reduction, as the humidity falls.

Jack

[jcanavera]

Originally Posted by Canoe stream

Morningtime moisture on windows? Even in cold weather I leave several windows unlatched at the opposite end of the trailer so that exhaled moisture has a way to get out.

Nope the inside of the trailer is so cool that the moisture condenses on the outside. I remember the first year that Twinke came with his new Safari and his 15K air conditioner. He had the insides so cool that the outside window glass was sweating .

Jack

[Mike Lewis]

Originally Posted by ptrvr

Thanks for the replies. I have one of those indoor/outdoor thermometers so guess I'll put the outdoor unit buy the A/C, turn it down real cool, let her run and see what happens.

thanks

Greg

Turning the temp controls down so the ac does not cycle can in some cases cause "ice up" in the unit if the humity is high. If you notice "snow" being spit out of the ac this is about to happen. This will be followed by a reduction in air flow from the ac outlets.---pieman

[jcanavera]

Originally Posted by Mike Lewis

Turning the temp controls down so the ac does not cycle can in some cases cause "ice up" in the unit if the humidity is high. If you notice "snow" being spit out of the ac this is about to happen. This will be followed by a reduction in air flow from the ac outlets.---pieman

I had this happen on my SOB down in Destin Fl. It ended up being a problem with my thermostat which caused the fan to shut down but not the compressor.

But it was interesting because the service guy noted that down in FL, and in a lot of high humidity locales, folks tend to run their fans on low speed. He noted that this tends to cause a lot of units to ice up due to the lower air flow. It might be wise to keep the fan speed on high to see if this helps in this scenario.

Jack

[Griswolds]

Your problem could be several issues. But start with the simple things first and cheap things. You cant hurt it unless your up there with a hammer and ice pick.

Dirty/Clogged Condenser coil(exterior)sometimes not visible but enough to stop the heat transfer. If it hasnt been done I sure its in need of it.

Dirty/Clogged Evaporator coil(interior)

Filter

The worst could be the start of a small leak, getting a charge will only band-aid the problem because all AC and heat systems are sealed.

Most units need the cover taken off every preseason and the coil cleaned.


PS.....if you need more help let me know