In a house I rebuilt a few years ago, I installed a dehumidifier in the crawl space because of wood floors above.
The owners are away this year and they asked me to check on why the power bill might be quite high, at about $80 a month lately. Nothing else has been running lately other than the refridgerator and the de-humidifier. I crawled down to peek at it and discovered that the coils were solidly iced up. Presumably, it has been running around the clock or so and making the meter spin. I unplugged it to let the poor thing have a rest while I figure something out.
There is a control dial on it that is set at about the halfway point. does anyone have a hint whether turning it back will solve the problem? The crawl felt nice and dry, considering the humidity we have had.
The concrete walls are sprayed with urethyene foam 1″ and I have a VB on the ground.
Excellence is its own reward!
Replies
piffin,
Sounds like it's low on freon. Turning down wont help.
KK
The short answer is: yes.
Being a serious dehumidifier user, never had this problem but I thought all dehumidifiers had builtin frost sensors that would turn them off. Apparently not.
Far as I know we've never frosted one up. Considering your location I'd check to make sure you have one that will operate properly at your air temps. Mine don't work well below 70* and we don't operate them then. No point in paying for electricity if you don't get performance.
To set the dial properly you should measure the rh in the crawlspace and adjust the dehumidifier accordingly. We use a simple solid state device that reads temp and rh. We aim for 60% rh, or a little less, this time of year. Those floors would also be happy.
If your dehumidifier, like ours, draws 7.5A, x 120v x 24 hrs = 4.32 kwh/day. Makes for a larger electric bill. In that crawlspace, presumably considerably less than our 20,000 cu ft, you shouldn't need to operate it but a few hours/day, depending on size.
I once installed a dehumidifier in a similar situation and found that with the small air volume it rarely came on, even with standing water. But that was a large commercial dehumidifier. Halfway on the dial might be correct, depending on the dehumidifier, but apparently isn't for yours. There really isn't any substitute for measuring the rh of the air and adjusting the dehumidifier accordingly.
PAHS Designer/Builder- Bury it!
As kkearney said, could be a low charge. More likely since it is several years old and in a crawl space, it is dirt. Take it outside and pull the case off of it and give it a bath. Airflow restrictions on either the eavaporator or condenser coil of any refrigeration unit will ruin the efficency, thus driving operating cost up. If it is not dirty, then it is most likely a low charge. Cheaper to replace the unit than have it worked on most of the time.
Dave
It's a very clean crawl so I doubt dirt restrictions. how would I diagnose low freon? A service call from an appliance guy is expensive out here, but would not be hard to pull it out top take in.
This is one of those, do a favor for the customer deals that earns brownie points but boils down to a PIA, especially since it is out of my area of expertise, so I appreciate the hints guys. Could save me a lot of wasted time. I'll run up there today to look it over..
Excellence is its own reward!
Make sure the fan is running. They will freeze up if it stops. Most fans require oiling at least once a year, there should be a place for it marked OIL on the motor. Maybe some are sealed now, but they were all bronze bearings with felts in the past.
Another thing is they can ice up if they run when the ambient temp is low, under 65F or so.
The humidistat may be stuck on. I have had to change them, but expect to pay $30-$40 for one. Make sure it will shut off properly. Sometimes they will cycle off and on when the knob is turned up and down, but don't respond to humidity at all.
My guess is air blockage through the coils from dirt and lint though.
Best bet is to replace the unit if it is in an unoccupied building where it can cause problems unnoticed.
Low ambient temps makes sense.
It is a cool crawl, and the DHer makes it cooler, IMO. I have an identical unit in another house that does a larger space with no problem but it is in a warmer location.
So
I'll look close at
clean fins,
controls,
RH and temps,
and maybe pull the unit to take to a service agent for a check up..
Excellence is its own reward!
I have a dehumidifier in my basement, same one has been running for 20 years or more. If the unit was new when you installed it a few years ago, then I wouldn't think it would be low freon, unless one of the soldered joints cracked. Maybe a warrenty issue at that point.
Twice I've found mine iced up. The first was due to dirt and sawdust (from my shop) had clogged the fins, preventing air flow. A stiff nylon brush and water cured that. The other time the humidistat lost it's mind and continued to let the thing run at the end of the season. I cycled it max to off, then reset it back to its normal setting, and no further problems.
Mine runs continuously in the basement from mid-May to the end of Sept. After that, the humidity drops and the thing cycles on and off till I unplug it in Nov, clean the tank with bleach (I've piped mine to the condensate pump from my air-handler drain), clean the coils, and put it to bed till next year.
Good luck.
Well, it looks like probably a mind control problem for this one.
The coils were clean enough to lick. I played with the dial like I was trying to tune in to Guy Lombardo ( didn't get any reception tho) and it came one at about 20% of the dial every time.
But - The plumber has it instaled with the drain hose looping up and back down into a p-trap. Loop is always lower than the drain on the machine but the "Full" light on front of unit is staying on.
I'm wondering if that means that water sitting in the hose registers as full and somehow impedes efficiency.
I'll be looking at it agian tomorrow..
Excellence is its own reward!
If the full light is on, the unit shouldn't be running. Unless someone decided to bypass the switch. There are two types of switches; a float switch, which is fastened to the chassis of the dehum'r and sticks into the tank, when level gets so high, it shuts off the unit. Sears models (and possibly others for all I know) use a pressure sensitive switch that sits at the bottom of the chassis under the tank. When water level (and therefore pressure) rises to the top, it shuts off the unit.
But you said that while twisting the knob, it came on at 20, right? Was the light on at the same time? If the light was on, and all is wired correctly, then it shouldn't come on, because it thinks the tank is full.
I'm confused about the loop to the p-trap. No part of the loop is above the drain, is that right? If that's so, then it really shouldn't effect operation, unless you have a bottom pressure switch on the tank and the loop is pulling the tank down, mimicking a full tank.
Ah well, hope all goes well on the morrow.
I never met a tool I didn't like!
lots of wet basements on some of our caretaker houses has given me a quick and dirty educatio on dehumidifiers..
there are two basic families: normal, and low-temp...
i will only buy the low-temp ones in New England.. and i've never seen them ice up in basements or crawls..
i have seen teh normal ones ice up all the timeMike Smith Rhode Island : Design / Build / Repair / Restore
Check the drain and resevoir for scum/algea buildup. The drain line may not be 100% blocked, but scuzzed up enough to reduce flow and cause the resevoir to remain at or near the full level.
Dave
I line up with Dave on likely causes. My coils froze when the condensate drain was blocked with construction dust and debris (ok, so I should build cleaner). Filled the pan, and everything froze from there. Cleaned the debris from the drain, and no problems in the 2 years since.
Low ambient temperature....
I got around this problem by trying two things that worked successfully...
1. Turned down the humidistat a little and placed one of those oil-filled electric radiators (on the lowest wattage setting and thermostat set at around middle) in front of the unit and ran a fan to blow warm air toward the dehumidifier.
Not too good for the ol' electric bill but it took care of the freezup problem.
2. Moved the humidifier to a location closer to a corner wall so the exhaust/dry air hits the wall and sortof creates a warm climate for the dehumidifier. After a bit of tweaking of the humidistat at this location, it's been running fine on its own without any freezup problems.
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Recently bought a Whirlpool model that works in lower ambient temperature - works GREAT. This one is at another house in the basement, draining directly into the floor drain.
One suggestion you may want to try is using a box fan in front of the exhaust side to blow the hot air back toward the dehumidifier.
This would not add too much to the power consumption.