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Topic: Iceberg (Read 767 times) previous topic - next topic

Iceberg

Any thoughts other then clogged drains why my roof a/c evaporator freezes up? After about 20 minutes the air flow starts to slow down because the evaporator turns into an ice cube. I'm going to make sure the drain tube is clear but was wondering what else would cause this?
Andy 1989 U300 40'

Re: Iceberg

Reply #1 –
You a/c evaporator needs to be cleaned. Not the outside coil but the inside coil. You have to remove the sheet metal covering from the top of the unit to access the coil. You can get a spray coil cleaner from an RV supply. It probably has a black / dark gray mold, etc clogging the air flow. After the coil is cleaned it won't freeze up any more.


2006 Nimbus 340'
Build #6353
Aug 2005
Motorcader #17139

Re: Iceberg

Reply #2 –
you might be low on freon
you can tap the line and add a fitting. A tech did this last year, but mine is starting to do the same. I'll upgrade to a 15,000 btu

Re: Iceberg

Reply #3 –
Not an expert on roof air but automotive units have a temp sensor in the fins of the evaporator that controls the "thermostatic expansion valve." As the temp drops, the sensor signals the valve to cut back the amount of refrigerant allowed into the evaporator. This should keep the air cold but not allow ice to build up. This is especially important in high humidity environments as the evaporator can ice up in just a few minutes.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Iceberg

Reply #4 –
Here is a link to a PDF describing the function of a TEV along with troubleshooting: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.danfoss.com%2FNR%2Frdonlyres%2FCA5E4257-4F6B-4F41-A268-8CB4FE6874DD%2F0%2FPFA00A102.pdf&ei=cb9lUJHYJoW9yQHD9IB4&usg=AFQjCNH3ATgAwEqBe8olJW3oGHpxZZ6qGA&sig2=I01mUdFQvts94qYTUyumnA

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Iceberg

Reply #5 –
I have used this stuff it's meant for coil cleaning.  Gary B. used it as well and he had good luck with it:

Air Conditioner Coil Foaming Cleaner-AC-920 at The Home Depot

Keith
Keith, Joyce & Smokey the Australian Cattle Dog
1995 U320 SE Extreme 40' WTBI Build # 4780, with a Honda CR-V hopefully still following behind.
Motorcade # 17030
FMCA # F422159

Re: Iceberg

Reply #6 –
Quote from: Keith and Joyce –
I have used this stuff it's meant for coil cleaning.  Gary B. used it as well and he had good luck with it:

Air Conditioner Coil Foaming Cleaner-AC-920 at The Home Depot

Keith
    I recently cleaned both coach ac's and both ac's on my house with that same stuff. Works well and makes the ac smell good.
Dean & Deirdre

2012 Arctic Fox 22GQ
Was 2003 U270