Any dehumidifier gurus out there?

I've got a dehumidifier, a few years old now. Recently I've been getting the 'defrost' warning light on all the time, supposedly indicating that either the ambient tempoerature is too low (it isn't) or that the air filter is clogged (it isn't).

The fan and compressor run apparently normally, but the unit is no longer collecting any significant amount of water. I've opened up the unit while running, and it's copper cooling coils feel about room temperature.

The model is a B&Q-branded WDH-610HA (see

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Any ideas what's wrong, please, and if it's fixable?

Thanks

Reply to
Lobster
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The link works without the terminal ) but there is no price. Doesn't look worth repairing if the powered bits are working. Perhaps it has lost its refrigerant?

Reply to
Roger Hayter

It has probably lost its gas. Fixable, yes - worth the cost of fixing, no..

Reply to
Harry Bloomfield

There's quite a useful fan in them. I use one permanently mounted in a louvred window high up in the conservatory to help ventilate it on really hot days...

Reply to
Chris Hogg

If the cold side of the coil (on the air intake) isn't getting cold after the compressor has been running for several minutes then it's lost its refrigerant gas and is not realistically repairable. The outlet side coil never gets cold of course.

NT

Reply to
tabbypurr

The coils should be very very cold. A wet finger should stick to them. It has a leak and lost the refrigerant. Not worth repairing. Sorry.

Reply to
Mr Pounder Esquire

It might be the solenoid that reverses the warm gas flow to melt the ice on the cooling coils has failed. I would investigate this and try and disable it before assuming the gas has gone.

This is now my 30 yo ebac homedry works. There is a 555 timer that triggers for 5 mins, once an hour to operate a solenoid that backfires warm gas through the cold coils melting any ice.

when I took it to Fiji I phoned ebac and they said because the heat and humidity would be so high I could just pull the spade connector off the solenoid and allow it to drip into the container all the time.

Reply to
Andrew

Lack of gas would have been my first guess too, I wondered if there is a charging point compatible with the cans you can get for car aircon.

But I think this is a very good call, and it is what I would look at first.

Reply to
newshound

newshound has brought this to us :

They use a crimped over then usually braised fill pipe seal after filling. They are not built to be refilled.

Reply to
Harry Bloomfield

it'd only leak out again. Butane etc are cheap & sometimes usable, but also explosive.

NT

Reply to
tabbypurr

Yes this works much like a fridge and hence if the coolant is gone you are just pumping nothing. I doubt its possible to recharge the system in these, though some up market ones can have the whole module replaced, probably not worth it for a cheapy. After all if you want to collect moisture you have to lower the temperature of the air so the moisture is released. Brian

Reply to
Brian Gaff

There is no positive evidence of a gas leak that we are aware of (yet).

It could be a failure of the mechanism that prevents or deals with ice on the condensers that has failed.

Reply to
Andrew

Well the cooling coils aren?t getting cold so *either* it?s leaked *or* it got an electrical problem. In both cases refilling randomly is a daft idea.

Tim

Reply to
Tim+

Refrigerant, not coolant. Coolant is the fluid used to transfer heat from a hot place to a cooler place by flow of the fluid (thermal siphon effect or with a pump) relying on latent heat absorption at the hot end and latent heat emmission at the cool end without involving any change of phase (solid to liquid or liquid to gas or vapour, for instance).

A refrigerant does something similar to the above but with the addition of changes of phase such as turning from a gas or vapour into a liquid, usually when under compression in a cooling coil of finned tubing at higher than ambient temperature to dissipate heat energy into the atmosphere (eg, the back of the fridge) before this, cooled to just above ambient and still compressed, liquid is returned to the part that needs cooling via a restrictor nozzle into a lower pressure cooling coil of pipework to absorb heat from the thing that needs cooling (eg the fridge interior) by virtue of the expansion of the refrigerant causing it to drop in temperature to below that of the thing to be cooled before it is returned to the compressor intake where it is compressed, raising its temperature, to be sent back to the cooling coils to condense it back into a liquid which can then be recycled ad infinitum (or for as long as the compressor keeps running).

Coolant is basically used just to reduce the temperature difference between a hot thing and its immediate surroundings whereas a refrigerant provides the means by which to cool a hot thing to a temperature *below* that of its immediate surroundings via the mechanism of phase change (typically, liquid to vapour).

Strictly speaking, this process of cooling by expansion and reheating by compression still works even if the refrigerant remains in its gaseous state throughout the whole cycle, it simply won't be as efficient as a system that utilises the effect of latent heat of evaporation and condensation with a carefully formulated refrigerant optimised for the particular temperatures involved.

You have to make sure the air temperature is lowered only in the location where the condensed out moisture can be conveniently collected into a holding tank which can either continuously drain away or else be regularly emptied. The dehumidifier has to direct the air to a 'cool spot' that's colder than any other part of the room which would otherwise act as the 'cool spot', accumulating condensed out moisture where it can cause harm.

Reply to
Johnny B Good

The cooling coils on my ebac homedry will never get cold if the solenoid remains activated, even though it doesn't need re-gassing.

Reply to
Andrew

This paragraph would be better if you removed the two "latents".

snip

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Reply to
Roger Hayter

I wasn't entirely sure myself but, on reflection, I think I did rather 'over-egg' this particular pudding. :-(

Reply to
Johnny B Good

Is the compressor definitely running not just the fan?

I had a "posh" Misubishi one that stopped working a few years back but fan was working. Finally last autumn I thought "kill or cure" and dismantled the beast. Fortunately before I did too much destructive investigation I spotted a bulge in a large square packaged electrolytic capacitor. Couldn't find an exact 450V(?) match but found a similar one at 350V from RS. bought 2, fitted one and it's been working perfectly since then, plus I now have a spare capaitor stored inside the unit for when it's required in the future.

:)

Reply to
www.GymRatZ.co.uk

Never seen that in a dehumidifier. Defrost is normally just switching off the compressor but keeping the fan on, if the evaporator drops below zero.

Reply to
Andrew Gabriel

Yes. Symptom is that the compressor casing gets hot, but the condensor (the normally hot coil) doesn't get hot. It can burn out the compressor because the compressor relies on the refrigerant to carry the heat away - there is usually a thermal trip on the compressor casing, but it doesn't always trip before the compressor coils short out.

Reply to
Andrew Gabriel

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