Dehumidifier Question

Had a dehumidifier given to me because "it overheats" . Inspecting the
unit I find that the evap coil is icing - which if I remember my
refrigeration correctly is an indication it's a little low on refrigerant .
Once the coil is totally iced , there's no air flow thru the unit , which
will overheat the compressor ...
Other than a slight vibration on the casing , this seems to be the only
problem . Is my memory correct ? I have access to everything needed to add
some R22 , including the gas .
This unit will be used in our camping trailer , assuming I can get it to
work right , the second one is going in my shop - gotta keep the machines
from rusting !
Reply to
Snag's Shop
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Generally, true, yes. Need to determine from age or lookup which generation of refrigerant it used for compatibility.
Reply to
dpb
if its old its R22
Reply to
Karl Townsend
Karl Townsend fired this volley in news: snipped-for-privacy@4ax.com:
And if it's a consumer unit, it has pinched-and-soldered fill/evacuation tubes rather than ports, meaning you've got some work ahead of you before the first ounce of gas goes in.
Lloyd
Reply to
Lloyd E. Sponenburgh
Karl Townsend fired this volley in news: snipped-for-privacy@4ax.com:
PS... corrosion or an obstruction in the capillary tube will cause the same symptom as low refrigerant, and unless you're up to replacing that, it's a goner.
Lloyd
Reply to
Lloyd E. Sponenburgh
================== Refrigeration line taps. Many suppliers but for an example see
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Most likely will need two, one for high side and one for low side to allow gauge attachment.
Reply to
F. George McDuffee
Tag on the unit says it uses R22 , and I know where to get some .
Reply to
Snag's Shop
Dad called 'em tap-a-lines , and I have a pair on hand from a dead freezer . Adding gas wouldn't have helped that one , compressor was running but not pumping . One week to the day after the warrantee expired .
Reply to
Snag's Shop
I doubt it's a plugged cap tube , this thing will ice the entire evap coil in under 30 minutes . And once it's iced , there's no airflow over either coil
Reply to
Snag's Shop
OK - why is that? (Inquiring minds ...) Bob
Reply to
Bob Engelhardt
IIRC it's because when the evap pressure is too low the refrigerant boils off too fast , chilling the coil below the target temp . It's been like 40-something years since I studied the subject . I found Dad's texts from when he studied it in the Navy when I was a teenager . Modern stuff ain't all that different ... the cycle remains the same , to paraphrase .
Reply to
Snag's Shop
"Snag's Shop" fired this volley in news:L3h7u.25856 $ snipped-for-privacy@fx16.iad:
Not "no-flow", snag, "reduced flow". Those cap tubes are balanced to the evaporator size.
Lloyd
Reply to
Lloyd E. Sponenburgh
I was referring to the air flow over the coils . That evap coil was 75% blocked in under 30 minutes . Part of the air output from the fan is directed to the compressor - to cool it , I assume .
Reply to
Snag's Shop
"Snag's Shop" fired this volley in news:2rj7u.39915 $ snipped-for-privacy@fx28.iad:
Not usually "directed", on older units, just "in the vicinity. They usually get a little coil breeze from the evap, and intake air breeze going to the condensor... but it's not _forced_ over the compressor can.
The older units used the really LARGE hermets, which had enough can area to dissipate most of the heat the refrigerant didn't carry away, and to handle it for a long time, even if the coolant isn't doing its work.
But -- I was addressing the issue of WHY it's freezing up, not whether or not the compressor would overheat.
It takes only a small partial obstruction of the capillary tube to present with that symptom. Same with fixed-capacity wall ACs, fridges, etc.
The lower the price, the less fastidious they are about removing all traces of contaminants and non-compressibles from the system. Some of those (like moisture in _any_ amount) will cause gradual corrosion of the sealed system from the inside-out.
Once the capillary tube has even so much as a flake of copper chloride stuck in it, it's gone.
Lloyd
Reply to
Lloyd E. Sponenburgh
Pressure and temperature have a relationship, in refrigeration. Often, lower pressure results in lower temp.
Can also be defective freeze stat.
. Christopher A. Young Learn about Jesus
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Reply to
Stormin Mormon
Should be a plate or sticker, some where.
. Christopher A. Young Learn about Jesus
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Reply to
Stormin Mormon
For a gas and go like this, only low side is needed.
. Christopher A. Young Learn about Jesus
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Reply to
Stormin Mormon
I've seen R12, in dehum. Also seen R500.
. Christopher A. Young Learn about Jesus
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Reply to
Stormin Mormon
Stormin Mormon fired this volley in news:evk7u.3671 $ snipped-for-privacy@fx01.iad:
Yeah, but most of the older ones were R22, Stormy.
I've got an ANCIENT GE commercial unit with steel coils and a hermet larger than your head that just keeps on keepin' on after 30+ years in heavy service.
Lloyd
Reply to
Lloyd E. Sponenburgh
Rare moment, when I'm not old enough to know some thing. Thanks, gramps.
What's the amp draw, on that old beast?
. Christopher A. Young Learn about Jesus
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Reply to
Stormin Mormon

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