joshuajim
Mojave Desert
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The other factor to consider is humidity. The higher it is the less cooling you will get.
RVing since 1995.
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Dave H M
IL
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Doug, ya just gotta let some sleeping dogs lie. ![[emoticon]](https://forums.goodsamclub.com/sharedcontent/cfb/images/biggrin.gif "biggrin")
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smthbros
WI
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Sunnysidebeach wrote:
One key point is; AC units need to cycle. That's why in a couple places we camped this summer, we had to raise the inside temp to 75 instead of 73 a couple days.
Why?
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poppa
Dallas, TX
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dougrainer wrote:1. 32 RV. A 15k will NOT cool the RV adequately in temps over 85 degrees. PERIOD. You need 2 AC units in RV's over 27 foot. Especially since Slide Outs are almost standard in Trailers. Do you have a slide out?
2. IR temp guns are NEVER used to determine Air temp in a AC system or a Refer system. You must use a digital thermometer to determine air temps.
3. The ONLY correct test on the performance of a AC unit after all variables have been verified(coils clean/filter clean/divider gasket) is a temp corrected AMP draw of the compressor.
4. RV AC units only hold about 1 lb of coolant. So, if you do have a leak, it will either cool or not. Not partially, as the coolant will have leaked out enough to not work at all. Doug I agree with everything but #2 an analog thermometer will work as well, does not have to be digital.
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poppa
Dallas, TX
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joshuajim wrote:The other factor to consider is humidity. The higher it is the less cooling you will get. less sensible cooling, still removing latent heat
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ktmrfs
Portland, Oregon
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dougrainer wrote:1. 32 RV. A 15k will NOT cool the RV adequately in temps over 85 degrees. PERIOD. You need 2 AC units in RV's over 27 foot. Especially since Slide Outs are almost standard in Trailers. Do you have a slide out?
2. IR temp guns are NEVER used to determine Air temp in a AC system or a Refer system. You must use a digital thermometer to determine air temps.
3. The ONLY correct test on the performance of a AC unit after all variables have been verified(coils clean/filter clean/divider gasket) is a temp corrected AMP draw of the compressor.
4. RV AC units only hold about 1 lb of coolant. So, if you do have a leak, it will either cool or not. Not partially, as the coolant will have leaked out enough to not work at all. Doug
on (1) our trailer is 32ft with two large slides. AC is a coleman Mach III 13.5K BTU. It will keep the trailer inside at 74F at temps up to the high 90's. BUT to do that it needs to come on when the inside temp hits 74. It will NOT cool the trailer down, For that yes, you need two AC units.
Now many trailers have massive air leaks on the ducted AC and not enough ducts. To fix that spend a day sealing up the gaps between the duct and vents and since most trailers use a long duct system, add a few more ceiling vents. Makes a big difference.
And talking about vents, IMHO many of the vents that come on trailers restrict airflow and aren't very adjustable. So, take them out and install aireport AC vents. easy to adjust, give 360 degree airflow and very low resistance in the full on position.
* This post was
edited 08/13/20 09:59pm by ktmrfs *
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!
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dougrainer
Carrolton, Texas
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poppa wrote:dougrainer wrote:1. 32 RV. A 15k will NOT cool the RV adequately in temps over 85 degrees. PERIOD. You need 2 AC units in RV's over 27 foot. Especially since Slide Outs are almost standard in Trailers. Do you have a slide out?
2. IR temp guns are NEVER used to determine Air temp in a AC system or a Refer system. You must use a digital thermometer to determine air temps.
3. The ONLY correct test on the performance of a AC unit after all variables have been verified(coils clean/filter clean/divider gasket) is a temp corrected AMP draw of the compressor.
4. RV AC units only hold about 1 lb of coolant. So, if you do have a leak, it will either cool or not. Not partially, as the coolant will have leaked out enough to not work at all. Doug I agree with everything but #2 an analog thermometer will work as well, does not have to be digital.
CORRECT. BUT, WHY would anybody have an Analog Thermometer in this day and age??????? Also, Analog Thermometers HAVE to be calibrated to be accurate. Having an Analog Thermometer is like having a needle display Multi tester. Doug
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mich800
Pontiac, MI
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smthbros wrote:Sunnysidebeach wrote:
One key point is; AC units need to cycle. That's why in a couple places we camped this summer, we had to raise the inside temp to 75 instead of 73 a couple days.
Why?
I think they may have that backwards. Short cycling is bad. It needs to have adequate run times to pull out the humidity. That is why too big a system can be bad.
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dougrainer
Carrolton, Texas
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mich800 wrote:smthbros wrote:Sunnysidebeach wrote:
One key point is; AC units need to cycle. That's why in a couple places we camped this summer, we had to raise the inside temp to 75 instead of 73 a couple days.
Why?
I think they may have that backwards. Short cycling is bad. It needs to have adequate run times to pull out the humidity. That is why too big a system can be bad.
AS it relates to Home systems, YES, having too large a system for a house, means the system does NOT RUN long enough to remove the humidity/moisture in the house. As it relates to RV's, it is a RARE RV that has too many roof AC's to overcool a RV. If the system is continually running(compressor) in hot weather, that is a good thing. It is doing its job. While it may be best to allow the Compressor to cycle, so you do not shorten its lifespan, that is the RV'ers choice. But there are Thousands of AC units that never shut off in temps above 85 degrees. BUT, having the correct amount of AC BTU's will allow the RV to cool down enough to cycle off. Doug
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mich800
Pontiac, MI
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dougrainer wrote:mich800 wrote:smthbros wrote:Sunnysidebeach wrote:
One key point is; AC units need to cycle. That's why in a couple places we camped this summer, we had to raise the inside temp to 75 instead of 73 a couple days.
Why?
I think they may have that backwards. Short cycling is bad. It needs to have adequate run times to pull out the humidity. That is why too big a system can be bad.
AS it relates to Home systems, YES, having too large a system for a house, means the system does NOT RUN long enough to remove the humidity/moisture in the house. As it relates to RV's, it is a RARE RV that has too many roof AC's to overcool a RV. If the system is continually running(compressor) in hot weather, that is a good thing. It is doing its job. While it may be best to allow the Compressor to cycle, so you do not shorten its lifespan, that is the RV'ers choice. But there are Thousands of AC units that never shut off in temps above 85 degrees. BUT, having the correct amount of AC BTU's will allow the RV to cool down enough to cycle off. Doug
Thank you. Mine is the same. Runs constantly to keep up. Never had a need to cycle it off in the RV. And I agree, never been in an RV that was over spec'd on the AC.
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