Faulty Dehumidifier. Hopefully an easy fix!!

[madnesstiger]

Hi All,

I've been handed-down an old dehumidifier (about 5 years old or so), and that I can use it if I can fix it! I have never had a dehumidifier before, but I have researched how the things work in principle.


Here's the problem:

When I turn the unit on, I am greeted with a 'clicking' noise, and the unit not collecting any water whatsoever.


Now, I have taken the unit to bits, and have found the following:

The user-knob is one single control. It controls the humidity setting, and operates a microswitch at the bottom-end to power on the machine. I have taken the switch unit out as shown below:

The power wires (one brown, and one purple) lead down to the compressor. The black wire leads to a small circuit board on the user panel which operates the on/off lights I assume.

The 'clicking' seems to be coming from inside the plastic box next to the compressor (is this the motor in here?!).

The plastic 'box' to the left of the compressor

Overview of dehumidifer

I know that:

The fan works fine, and the microswitch which recognizes the fill-tank operates successfully also.


I have a volt-meter, some basic electrical tools, and very basic physical electrical experience.

Does anybody feel they can help me out here in terms of any checks I can carry out or whatever? And also, should I maybe be looking towards the controls unit, or the motor/compressor components?


The dehumidifier model is a BCM ltd Dehumidifier BCM101 (DE22GY-GB)


Thanks for your time, and hope the photos are of use!

MT

 

[Leccy758]

The plastic box next to the compressor contains the motor relay, this switches the compressor from its start winding to its run winding (motor is inside the compressor)

A clicking noise could be the compressor not starting/trying to start

to test a compressor disconnect from mains, remove the plastic cover behind which sits the mains supply lead and wiring from the control circuit,

pushed onto the side of the compressor is a small unit that should have three female connectors (occasionally 2 with a seperate one)

remove this and you should see three pins (1 for the start winding, 1 for the run winding, 1 common) test the resistance between pins

start to common low resisitance
run to common higher resisitance
start to run should be equal to the total resisitance of start to common and run to common

if you can identify the wires leading to the compressor from the control and you are confident/competant you can connect a seperate supply to just try the compressor on its own (once the start relay is refitted/or before testing the motor by removal of the start relay)

if you are unsure of what wires to disconnect to do this then I would advise you not to try

As an aside typical faults with dehimidifiers when brought in to me for not working are

Extract fan jammed/not rotating
Clogged matrix

 

[madnesstiger]

Hi Leccy,

Thanks awfully for your reply, and your advice.

I will go ahead and try some of your tips, and will most-likely learn something new in the process about electrics (if I live to remember any of it! lol).

As it was a 'freebie', I feel I have nothing to lose, and will let you know how I get on.

As for the rest of the unit, I have given it all a good clean whilst waiting for any replies to this thread, and have tested that the fan works - which it does (also, only works when the 'fill-tank' microswitch is depressed (which can only be a good thing!).

Thanks again.

MT

 

[madnesstiger]

Hi again,


I've done as advised in the 2nd post, and hope the following evidence can help somebody on my way to finding my problem!

As I've mentioned before, I am a novice when it comes to electronics, so please excuse any schoolboy errors!

Firstly then, I removed the plastic cover to find the following article, which I removed as shown...

This was slotted onto 2 metal pins (protruding from the compressor). There is a 3rd pin, which has a black wire attached (I'm guessing this is the 'common').

The diagram below shows the readings I got when measuring the resistance betweeen the 3 pins. I had the multimeter set to '2000' I think! The colours denote the coloured probes used on each pin to record the measurements (black and red).

If I'm right in guessing the top pin is the 'common', then I can confirm that the sums tie-in with what was mentioned in the 2nd post above, by Leccy.

So, with the results as they are, what can be concluded from this test?

If it helps at all, I can also confirm that the 'clicking' is coming from the small article shown in the photo above, and seems to be very 'rattly' when gently shaken (not sure whether this is the norm or not!).

Thanks again guys... hope you can help


MT

 

[madnesstiger]

I've tried measuring the resistance between either end of the coil on the solenoid (shown in photo in above post), and set my multimeter to '200 ohms'.

I get a result of ~007

This seems to be a low reading. Could it be pointing toward a fault with the solenoid, and causing the 'clicking' noise?


MT

 

[madnesstiger]

Just a quick update...

I've managed to find a solid-state relay at a local shop for just £6.99 to replace the one I removed earlier.

I've since fitted this new relay, and powered-up the dehumidifier.

I'm pleased to say that the clicking noise has completely disappeared. However, I've left the unit turned on, and will find out soon if it's actually drawing in any moisture. If not, then I guess it may well be down to the motor/compressor, and is time I thought about replacing the whole thing, rather than attempt a repair!

So, for now, I'll see what happens over the next few hours or so.