Dehumidifier question

What would cause a dehumidifier to ice up? I've had this unit for a LONG time (25+ years), and it's never done this before. The ambient
temperature in my basement is about 70F, but it's pretty damp. The fins are surprisingly clean, as is the filter, and there's good airflow (a shop rag sticks to the front).
After a couple of hours rubnning, there's a significant ice accumulation. The other day, when I discovered this, there must have been five or more ponds of ice encasing the whole front of the machine.
So, what's the deal? If this is low refrigerant, could I get someone to recharge it, or do I just spring for a new one?
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Proly low refrig. Proly get a new one. If you could find an intermittent timer, you might could get more life out of it, by cycling it short of the icing point. But man, you got yer money's worth. Who made this unit? Heh, you won't be gettin 25 years from anything (HD, pc richard) today -- lucky to get 5 years. You could just take a window A/C, and run it inside, arrange for drip, but someone mentioned that these will ice up, as well, but for diff. reasons. I think I tried this, and it iced up.
--
EA



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"Existential Angst" wrote in message

Proly low refrig. Proly get a new one. If you could find an intermittent timer, you might could get more life out of it, by cycling it short of the icing point. But man, you got yer money's worth. Who made this unit? Heh, you won't be gettin 25 years from anything (HD, pc richard) today -- lucky to get 5 years. You could just take a window A/C, and run it inside, arrange for drip, but someone mentioned that these will ice up, as well, but for diff. reasons. I think I tried this, and it iced up.
--
EA

Are the fins clean on the evap. coil_and_the condensor coil? Mine was doing
this. Once I got both coils completely free of crap, it stopped.
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I think the failure of the defrost thermostat is a fairly common problem.
An example replacement item:
http://www.repairclinic.com/PartDetail/Defrost-Thermostat/635443
At 44 bucks it'd be tempting to jerry-rig a relay to a timer and just have it defrost once every X hours.
It could also be a problem with the airflow.
I have 3 dead dehumidifiers, one runs fan and compressor fine but does nothing (that probably has a low charge), another runs the compressor but has a dead fanmotor, another has a compressor that won't start but the fan runs fine- guess what little project I'm in the middle of... a new motor is a 120-150 bucks, a new dehumidifier is 150-300.
Dave
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wrote:

I think the failure of the defrost thermostat is a fairly common problem.
An example replacement item:
http://www.repairclinic.com/PartDetail/Defrost-Thermostat/635443
At 44 bucks it'd be tempting to jerry-rig a relay to a timer and just have it defrost once every X hours.
It could also be a problem with the airflow.
I have 3 dead dehumidifiers, one runs fan and compressor fine but does nothing (that probably has a low charge), another runs the compressor but has a dead fanmotor, another has a compressor that won't start but the fan runs fine- guess what little project I'm in the middle of... a new motor is a 120-150 bucks, a new dehumidifier is 150-300.
================================================Yup, I got a similar "collection". I forgot about the defrost thermostat, so a timer really could extend the useful life, visavis a truly dying unit from leaking refrigerant.
DeLonghi, makes a nice unit, with a pump, that allows you to direct condensate away and overhead.... worktid great until it broke. Nice feature, cuz water can be prodigious. So now I just parked the unit over a shop drain, which I'm really fortunate to have. We'll see what else breaks....
I tried using the condensate to keep the coolant tank in the fadal full, but goddamm, half the time it just overflows the tank..... wow....
--
EA


Dave



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On Tue, 24 May 2011 04:53:36 -0700 (PDT), Dave__67

shop eBay for spare parts: http://tinyurl.com/3zjwk7j
Make sure that's likely the problem first. After a day or more disconnected, run it and make sure its pulling water out at a decent rate. Check that it doesn't frost up right away.
if you haven't got the gauges and R22, it will cost ya too much to recharge. unless you want this as an excuse to get tools. FWIW, I take any repair as an excuse to get more tools.
Karl
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Well, I just checked, and there is no such device in this unit. Just a humidistat, a fan, a compressor, a float switch and a motor cap.
It's running now (been running OK for a couple of hours. There's a small amount of ice on the cold coils, and it's dripping at a rate of about 10mL/minute which equates to 14.4 liters per day or 30 pints per day, which is probably near where this thing was spec'd. I've been running it today with the air filter removed. Even though it looked clean, I just washed it with soap & water and put it back on. Maybe this was all a false alarm?
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rangerssuck wrote:

This guy thinks your condenser needs a wash: http://wiki.answers.com/Q/Why_does_your_dehumidifier_ice_up
--Winston
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That looks reasonable. Four screws will remove the fan and its motor and expose the back of the coils. I ought to be able to hit it with some simple green and a garden hose. Or, If I'm feeling adventerous, with my rather anemic pressure washer.
I found a label, and this thing is rated at 60 pints/day. It's doing about half that right now, but there's a generous coating of ice on the coils. It'll be interesting to see how well it works after cleaning. This is certainly worth an hour of my time.
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wrote:

That looks reasonable. Four screws will remove the fan and its motor and expose the back of the coils. I ought to be able to hit it with some simple green and a garden hose. Or, If I'm feeling adventerous, with my rather anemic pressure washer.
I found a label, and this thing is rated at 60 pints/day. It's doing about half that right now, but there's a generous coating of ice on the coils. It'll be interesting to see how well it works after cleaning. This is certainly worth an hour of my time. =====================================================Hopefully the pressure washer is very anemic, cuz you can flatten fins in no time with these, so be careful. Hmmm, I'll take a look at my coils, as well. :)
--
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Existential Angst wrote:

(...)
Good luck guys. Please report back.
--Winston
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rangerssuck wrote:

Yeah, I'd be interested, too. Let us know if it works.
Bob
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"Winston" wrote in message wrote:

This guy thinks your condenser needs a wash: http://wiki.answers.com/Q/Why_does_your_dehumidifier_ice_up
--Winston
That's exactly the procedure I used to fix mine. It's starts to ice up after about 2 years, and this cleaning fixes it every time.
Garrett Fulton
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Dave__67 wrote:

You don't have to jerry-rig anything: http://www.google.com/search?hl=en&q=plug-in+timer+switch
Cheers! Rich
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You don't understand dehumidifiers or what he posted.
--------
"Rich Grise" wrote in message You don't have to jerry-rig anything: http://www.google.com/search?hl=en&q=plug-in+timer+switch
Cheers! Rich
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Just plain old...not enough air flow for the humidity. Clean the fan blades and filters. Check if the fan motor is seizing or overheating. This is common with a sudden humidity rise and first turning the units on.
Next time start it and then turn it off until the condensation starts to flow. Turn it back on again. It is usually fine then.
I doubt low refrigerant would do that but rather overheat the compressor.
------------
"rangerssuck" wrote in message
What would cause a dehumidifier to ice up? I've had this unit for a LONG time (25+ years), and it's never done this before. The ambient temperature in my basement is about 70F, but it's pretty damp. The fins are surprisingly clean, as is the filter, and there's good airflow (a shop rag sticks to the front).
After a couple of hours rubnning, there's a significant ice accumulation. The other day, when I discovered this, there must have been five or more ponds of ice encasing the whole front of the machine.
So, what's the deal? If this is low refrigerant, could I get someone to recharge it, or do I just spring for a new one?
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On 2011-05-24, Josepi <J.R.M> wrote:

    Actually -- it *does* cause icing. The boiling point of the refrigerant is a function of the pressure. The lower the pressure, the lower the boiling point. With enough refrigerant, the low-side pressure is high enough so the temperature is low enough to condense the water out of the air, but not low enough to form ice. Let some leak out, and the temperature dives far enough to cause icing. I've experience this more than once in the house AC (real refrigative AC, not Gunner's swamp cooler, which does not work around here).
    If you have a gauge set, look at the low side gauge, and you will see a separate temperature scale for two or more refrigerants. Mine has them for R-22 and R-134a.
    R-22 reaches freezing (32 F) at something like 5" Hg (above atmospheric pressure), while R-134a reaches the same temperature at a more extreme vacuum of 35" Hg above atmospheric pressure.
    The high side associates 32 F with about 50 PSI for R-22 and R-134a appears to be off scale for 32 F.
    However, when it comes to recharging the dehumidifer, look it over *before* getting refrigerant and a gauge set. At least the one which I have has no connection ports and valves for the manifold hoses. What it appears to have is crimp-off seals on the end of copper tubing. I've seen the tool for making those -- but don't have one of my own. It squeezes the copper tubing in two places -- one to make a seal, and another to squish through the copper and part the original tube off. To recharge something like this, you would probably need to cut the tubing off below the crimp, braze some more tubing on to give enough length to repeat the crimp-seal when you get enough refrigerant in the system. (Or perhaps, braze on some good valves so you can recharge it again in the future.) Oh yes -- you would also need a serious vacuum pump to clean out the system of air and moisture once it has been opened to the atmosphere.
    And -- you need to be able to *get* the refrigerant. Getting R-22 is rather difficult without a license these days. :-)
    The current outside humidity is about 67%,and the inside humidity at 40%. About 8:00 this morning, it was about 93%.
    And yes -- a swamp cooler can really freeze you out if the humidity is low enough. I grew up in South Texas and had plenty of experience with that. But here (too close to Washington DC) the summertime humidity is high enough so you can't buy a swamp cooler, and can't find an AC repairman who has even seen one most of the time.
    Enjoy,         DoN.
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Can you come to Yonkers, NY and check out my A/C??? :) Too bad you dint go to Eastec... you coulda stopped by me on the way up!!
--
EA


>
> Enjoy,
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So to understand this more.... The evaporator may have more "vacuum" on it and the evaporation process happens more efficiently ,due to easier evaporation, but the high pressure side is not really affected and still the same old liquid state?
----------
"DoN. Nichols" wrote in message
Actually -- it *does* cause icing. The boiling point of the refrigerant is a function of the pressure. The lower the pressure, the lower the boiling point. With enough refrigerant, the low-side pressure is high enough so the temperature is low enough to condense the water out of the air, but not low enough to form ice. Let some leak out, and the temperature dives far enough to cause icing. I've experience this more than once in the house AC (real refrigative AC, not Gunner's swamp cooler, which does not work around here).
If you have a gauge set, look at the low side gauge, and you will see a separate temperature scale for two or more refrigerants. Mine has them for R-22 and R-134a.
R-22 reaches freezing (32 F) at something like 5" Hg (above atmospheric pressure), while R-134a reaches the same temperature at a more extreme vacuum of 35" Hg above atmospheric pressure.
The high side associates 32 F with about 50 PSI for R-22 and R-134a appears to be off scale for 32 F.
However, when it comes to recharging the dehumidifer, look it over *before* getting refrigerant and a gauge set. At least the one which I have has no connection ports and valves for the manifold hoses. What it appears to have is crimp-off seals on the end of copper tubing. I've seen the tool for making those -- but don't have one of my own. It squeezes the copper tubing in two places -- one to make a seal, and another to squish through the copper and part the original tube off. To recharge something like this, you would probably need to cut the tubing off below the crimp, braze some more tubing on to give enough length to repeat the crimp-seal when you get enough refrigerant in the system. (Or perhaps, braze on some good valves so you can recharge it again in the future.) Oh yes -- you would also need a serious vacuum pump to clean out the system of air and moisture once it has been opened to the atmosphere.
And -- you need to be able to *get* the refrigerant. Getting R-22 is rather difficult without a license these days. :-)
The current outside humidity is about 67%,and the inside humidity at 40%. About 8:00 this morning, it was about 93%.
And yes -- a swamp cooler can really freeze you out if the humidity is low enough. I grew up in South Texas and had plenty of experience with that. But here (too close to Washington DC) the summertime humidity is high enough so you can't buy a swamp cooler, and can't find an AC repairman who has even seen one most of the time.
Enjoy, DoN.
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--
The pressure of the HP side is basically controlled by the pump speed
and the size of the expansion orfice- so yes, as long as there is
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