Jayco RV Owners Forum
 


Reply
 
Thread Tools Display Modes
 
Old 05-09-2015, 01:07 PM   #1
Member
 
Join Date: Sep 2014
Location: Cedar Park
Posts: 88
AC evaporator coil freezing up

Good afternoon -

First-time RV owners... We have a 2015 Jay Flight 32BHDS that we took delivery on in December. It has two Coleman Mach rooftop AC units (15K BTU main ducted unit with wall-mounted thermostat and a 13.5K BTU unit in front bedroom with controls in shroud at ceiling integrated with unit). We've camped several times using AC with no problems.

Last weekend I was running only the main 15K ducted unit and it ran most of the afternoon and night. The next morning no air was coming out of ducts. Upon inspection I found that my evaporator coil had iced up. We shut it down and just ran the 13.5K front unit Sat and Sunday. Both evap and condenser coils are pristine (as you would expect on new trailer).

Could this just be normal reaction to user (me) violating "best RV AC practices"? We had thermostat set pretty low (65-70) and nighttime temps outside got down into the 60s. Fan was on Auto and unit ran pretty much constantly. From all I've read online since we got back it sounds like I should have had thermostat set higher (ex. 78) and had fan set to "On" (instead of Auto) and "High".

Appreciate any tips and advice.
__________________

__________________
2015 Jay Flight 32 BHDS (Elite, Technology, Thermal pkgs, 50-amp)
1999 Ford F-250 7.3L Powerstroke 4x4 Lariat Crew Cab SRW 3.73
6.0L Upgraded Transmission Cooler
Autometer Gauges (EGT, Trans & Water temp, Boost)
K&N Cold Air Intake;
MBRP 4" Turbo Back Exhaust
Curt Class IV Receiver Hitch
Prodigy P3 Brake Controller; ProPride 3P Hitch 1400#
dsmith3 is offline   Reply With Quote
Old 05-09-2015, 02:20 PM   #2
Senior Member
 
Grumpy's Avatar
 
Join Date: Nov 2011
Location: Where ever the boss says we're going.
Posts: 5,037
If it is humid, running the fan on low will cause icing problems. I always run ours on high unless we are just using it to circulate the air then I will use low. The cooler outside temps probably just enhanced the problem.
__________________

__________________
DISNEY LOVERS
PINNACLE 2015 38FLSA. aka: "Roam Sweet Home"
Grumpy is offline   Reply With Quote
Old 05-09-2015, 03:47 PM   #3
Senior Member
 
herewego's Avatar
 
Join Date: Oct 2014
Location: Alvin
Posts: 1,095
Low on Charge .......................
__________________
Roy & Joyce
Alvin Texas
Delta German Shepard (She thinks she is a person)
2017 Eagle 330RSTS
2014 Ram 3500

herewego is offline   Reply With Quote
Old 05-09-2015, 04:30 PM   #4
Senior Member
 
Grumpy's Avatar
 
Join Date: Nov 2011
Location: Where ever the boss says we're going.
Posts: 5,037
Quote:
Originally Posted by herewego View Post
Low on Charge .......................

Right from the owner's manual:

II. Operation During Cooler Nights (Cooling

Operation).
It is important, when the outdoor temperature drops in the
evening or during the night to below 75 degrees F., that the
thermostat (temperature control) be set at a midpoint between
“Warmer” and “Cooler”. If the setting is at “Cooler”, the
evaporator coil may become iced-up and stop cooling. During
the day when the temperatures have risen above 75 degrees F.,
reset the thermostat switch to the desired setting.
NOTE
Should icing-up occur, it is necessary to let the cooling
(evaporator) coil defrost before normal cooling operation is
resumed. During this time, operate the unit in the “HIGH
FAN” position with the system at maximum air flow. When
increased or full air flow is observed, the cooling coil should
be clear of ice.
__________________
DISNEY LOVERS
PINNACLE 2015 38FLSA. aka: "Roam Sweet Home"
Grumpy is offline   Reply With Quote
Old 05-09-2015, 09:02 PM   #5
Member
 
Join Date: Sep 2014
Location: Cedar Park
Posts: 88
Thank you, Grumpy. This sounds like exactly what occurred in our situation (ran the AC at low setting at night with outside temps dipping down to the 60s).

I will know better now.
__________________
2015 Jay Flight 32 BHDS (Elite, Technology, Thermal pkgs, 50-amp)
1999 Ford F-250 7.3L Powerstroke 4x4 Lariat Crew Cab SRW 3.73
6.0L Upgraded Transmission Cooler
Autometer Gauges (EGT, Trans & Water temp, Boost)
K&N Cold Air Intake;
MBRP 4" Turbo Back Exhaust
Curt Class IV Receiver Hitch
Prodigy P3 Brake Controller; ProPride 3P Hitch 1400#
dsmith3 is offline   Reply With Quote
Old 05-10-2015, 09:14 PM   #6
Senior Member
 
tugboat95's Avatar
 
Join Date: Jul 2014
Location: New Bern
Posts: 403
Don't know exactly why but this is exactly the same thing that happened to us last time out. Ran it on low with temps in the low 70's and it froze up. Worked great in the daytime but froze up every night. Thought I had a low charge. Might exam this scenario a little more before I spend some money.
tugboat95 is offline   Reply With Quote
Old 05-10-2015, 10:38 PM   #7
Senior Member
 
VicS1950's Avatar
 
Join Date: Apr 2013
Posts: 517
Quote:
Originally Posted by tugboat95 View Post
... Might exam this scenario a little more before I spend some money.
It sounds more like it is operating conditions, not low charge.

Jayco gives the proper operating settings, but from what I saw doesn't mention why.

Comfort cooling is a combination of lowering the room temperature and de-humidification. If the temperature is lowered too quickly without removing moisture from the air then the space can feel cool, but clammy and uncomfortable.

The humidity is lowered (moisture removed) by the water in the air condensing on the evaporator coils to trickle down, collect in a pan, and then is sent to a drain. That is why you get a stream of water out of an operating air conditioning unit. As an example, you will get more water out of an operating A/C unit in humid Florida than you will in dry Arizona areas.

The air flow over the evaporator coil is critical to keep the coil temperature from getting too low. If the air flow doesn't keep the coil from getting below freezing then the moisture in the air will cause frost to build up on the coil rather than trickling down and out to the drain. As more frost builds up it further blocks the air flow which sets up a deteriorating condition. That causes the evaporator coil to "freeze up" or get covered with ice. Once covered in ice there is no air flow, the room temperature stays high because the air flow is blocked, the thermostat is never satisfied, the A/C unit runs full out without cooling the room, and evaporator coil becomes an ice maker.

Night operating with low load on the A/C system, low ambient temperatures, and low fan speeds sets up conditions which can cause coils to freeze up. A dirty air filter will also restrict air flow and can contribute to the problem.

Keeping the air filter clean and setting the controls at night as Jayco suggests should avoid your problems.

FWIW. vic
VicS1950 is offline   Reply With Quote
Old 05-10-2015, 11:18 PM   #8
Member
 
Join Date: Sep 2014
Location: Cedar Park
Posts: 88
Freeze Sensor disconnected

In addition to running at night with thermostat set too low, I found that my freeze control sensor was disconnected from the evap coil when I removed AC shroud. See loose white wire in attached photo. Will definitely need to place that back between the fins in the coil.
Attached Thumbnails
AC freeze sensor disconnected.jpg  
__________________
2015 Jay Flight 32 BHDS (Elite, Technology, Thermal pkgs, 50-amp)
1999 Ford F-250 7.3L Powerstroke 4x4 Lariat Crew Cab SRW 3.73
6.0L Upgraded Transmission Cooler
Autometer Gauges (EGT, Trans & Water temp, Boost)
K&N Cold Air Intake;
MBRP 4" Turbo Back Exhaust
Curt Class IV Receiver Hitch
Prodigy P3 Brake Controller; ProPride 3P Hitch 1400#
dsmith3 is offline   Reply With Quote
Old 05-10-2015, 11:18 PM   #9
Member
 
Join Date: Jan 2014
Location: Pacific Northwest
Posts: 45
Rule of thumb we have in the Commercial A/C business... If you set your cooling setpoint lower than 68ºF, the evaporator will begin to ice up.
__________________
2014 Jayco Jayflight Swift SLX 184BH Baja
2016 Toyota Tundra DC 5.7L

Nights Camped in 2015 - 24
Nights Camped in 2016 - 9
Socco1 is offline   Reply With Quote
Old 05-14-2015, 10:49 AM   #10
Senior Member
 
mike837go's Avatar
 
Join Date: May 2015
Location: Campbell Hall
Posts: 2,837
Please pardon my ignorance, but why is an modern A/C unit designed to allow the evaporator coils to drop below freezing (0*C)?


We're dealing with human comfort, not keeping the ice cream solid.
__________________

__________________
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck


Sitting in The Cheap Seats.
And proud of it!
mike837go is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia State Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -6. The time now is 06:33 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2002-2016 Social Knowledge, LLC All Rights Reserved.