Timed dehumidifier.

Vara

Vara

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With the onset of electricity charges at Dover I have to rethink my winter strategy... It was turn it on and leave it on, and as a result I had a lovely dry boat and because of this reckless attitude the planet is going to hell in a handcart.

Dehumidifier which can be controlled by timer plug is required, the one I have at the moment does not automatically restart. Desiccant one preferred.

Recommendations?
 
Basic Dehumidifier

I use this one as it is as basic as you can get with a low power mode, the ability to plug in via a cheap external mains timer, a continuous drain facility and a manual humidistat to avoid over drying.

With the external vents blocked and doors/cupboards left open it soon reaches the set level and after that only comes on occasionally. It only consumes 360w in low power mode.

http://www.dehumidifiers-direct.co.uk/contents/en-uk/d90_ecoair-dd122FW-simple.html
 
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captainboo said:
I use this one as it is as basic as you can get with a low power mode, the ability to plug in via a cheap external mains timer, a continuous drain facility and a manual humidistat to avoid over drying.

With the external vents blocked and doors/cupboards left open it soon reaches the set level and after that only comes on occasionally. It only consumes 360w in low power mode.

http://www.dehumidifiers-direct.co.uk/contents/en-uk/d90_ecoair-dd122FW-simple.html
Click to expand...

We've got one of them - works well and even without a timer the power consumption is not massive.
 
Are the desiccant ones better than the compressor type dehumidifiers? We have the latter which works well, but it has iced up badly a couple of times over the last few years, when the the termerature has dropped well below freezing. On one particular visit to the boat it looked like there was a small iceberg residing inside the unit. This makes me nervous about a malfunction and all sorts of horrible consequences!

If the desiccant type units are immune to this, I assume they are safer to be left running in sub zero temperatures? Or is that an over simplification?
 
Best combined with a couple of greenhouse heaters on thermostat switches. Then when below say 7C the heaters come on as well to avoid complete freeze

That's our attempt anyway. And always interesting reading the max and min temps since last visit, as displayed on the thermostat plug (bought at Homebase)
 
Electric Dehumidifiers - warning

Be very careful about leaving mains-powered dehumidifiers unattended in your boat. There have been several cases of yachts being "lost" whilst on shore over the winter to electrical fires that were directly connected to (or suspected to have been) these devices. This includes people we know personally, not just hearsay.

Ian, Nestaway Boats Ltd
 
nestawayboats said:
Be very careful about leaving mains-powered dehumidifiers unattended in your boat. There have been several cases of yachts being "lost" whilst on shore over the winter to electrical fires that were directly connected to (or suspected to have been) these devices. This includes people we know personally, not just hearsay.

Ian, Nestaway Boats Ltd
Click to expand...

Name rank and number please, my insurance co is totally relaxed about 24/7 mains, heating and dehumidifier. This suggests to me that concerns about dehumidifiers are slightly overblown.
 
Dehumidifier fires

Reference comment: "Name rank and number please"...

I'm Ian Thomson from Nestaway Boats Ltd - we make and sell sectional nesting dinghies. We have nothing to do with selling or installing dehumidifiers, nor anything that conceivably rivals dehumidifiers, ie no vested interest in and no expertise on dehumidifiers.

But we do know of at least two fires that have been caused by, or are believed to have been caused by (it can be difficult to be 100% certain after the event), mains dehumidifiers left on yachts, within the last ten years. I do not know the manufacturer of the dehumidifiers involved, nor how old they were, nor if dehumidifier safety has been improved since these incidents. In both cases the insurance companies settled the claim.

We cannot reveal owner/boat names without permission of those involved but a quick Google search would seem to suggest that this may be a potential problem worth at least knowing about and considering when purchasing a dehumidifier, choosing where to locate it within the yacht, programming it, etc.

I'm sure the vast majority of them are fine but like anything electrical they can go wrong and the marine environment rarely seems to help.

Hope that is useful.

Ian
 
Vara said:
With the onset of electricity charges at Dover I have to rethink my winter strategy... It was turn it on and leave it on, and as a result I had a lovely dry boat and because of this reckless attitude the planet is going to hell in a handcart.

Dehumidifier which can be controlled by timer plug is required, the one I have at the moment does not automatically restart. Desiccant one preferred.

Recommendations?
Click to expand...

I have had one of these for a year, used last winter on the boat and since then every day to dry laundry at home. Very good indeed. Restarts at same settings as left on, comes with drain hose attachment. http://www.dehumidifiersuk.com/p/5052426/meaco-dd8l-junior-85-litre-dessicant-dehumidifier.html It is sold as being suitable for boats.

They were out of stock last week when I ordered a second one for the house to replace an very old but now dead Ebac, but claim they will have stock again very shortly. The Ebacs all restart on timer power-up, but only at an "economy" setting, not at whatever setting you left them on.

The first dehumidifier I had for the boat was a compressor type sold by a large mail order chandlery as specifically designed for use on boats. It worked OK first winter on the boat, but when I took it out of storage in the loft and turned it on in the boat the next winter it would not extract any water, although the motor/fan whirred. Turned out it was by then three days outside warranty, although it had only actually been used four months. Got nowhere with chandlery and importer.

I strongly suspect that compressor types dislike long periods of unuse: they do tell me in my car manual to use the aircon (same fridge-type technology as a compressor dehumidifier) even in winter.
 
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nestawayboats said:
Hope that is useful.

Ian
Click to expand...

Yes - it is ...

Whilst the majority on here are usually quite sensible, all it takes is for someone to be reading this thread - wack on a de-humidifier on their own vessel without thinking and they run the risk of damaging their boat ...

Apart from de-humidifier internal malfunction - which none of us are likely to pre-diagnose, other "safety" aspects of deploying a mains de-humidifier ..

1) Appropriate fuse in the plug.
2) Plug kept away from areas where water may accumulate (ie the floor!)
3) Check on the shorepower connection - appropriate overload and earth leakage devices in place
4) External drain -> drain via where? Seacock & skin fitting? Above water? Pipework needs checking if you're going to leave it open.
5) Internal drain -> Auto cutoff when tank is full
6) De-humidifier placement - they're usually on castors - so somewhere secure - do not block the vents or place below where material is hanging that could fall and block the vent.

Anything else?
 
NDG said:
Are the desiccant ones better than the compressor type dehumidifiers? We have the latter which works well, but it has iced up badly a couple of times over the last few years, when the the termerature has dropped well below freezing. On one particular visit to the boat it looked like there was a small iceberg residing inside the unit. This makes me nervous about a malfunction and all sorts of horrible consequences!

If the desiccant type units are immune to this, I assume they are safer to be left running in sub zero temperatures? Or is that an over simplification?
Click to expand...

Yes, the dessicant type is far better. They are immune to the low temperature operating problems and actually slightly warm the air passing through them. At first sight, they consume more power than a compressor type, but they are more efficient at extracting humidity from the air and will run for less time for a given drying effect, so they do not work out any more expensive to run.
 
nigelmercier said:
Do these have a reservoir of anhydrous calcium chloride? What happens when it is saturated?
Click to expand...

No, those are the cheap, single shot things.

The dessicant dehumidifiers we are discussing here have a porous disk of some sort of mineral that attracts water. This disk extends into a duct joining the main air input and output of the dehumidifier with a fan that is driving the air flow through it and it is rotated slowly by an electric motor. As the air passes through the disk, it absorbs some of the humidity in it. The rotation then takes the moistened area of the disk round into another chamber where warm air is blown through it to drive off the water and the warm, moist air is blown through a heat exchanger that is cooled by the main airflow before it leaves the dehumidifier - condensing out the evaporated water which is then collected in the tank or discharged through the drain tube.

I guess that the disk will slowly get poisoned with dust and air pollution, but I've not seen any life expectancy quoted. Ours has run pretty much continuously on the boat for two full winters (November to March) and shows no sign of losing its efficiency. It has no difficulty extracting several litres of water from the air in a 24 hour period.
 
Dessicant Dehumidifier

+ 1 for the Dessicant type Dehumidifier

Bought a ECOAIR DD122FW "Simple" Dehumidifier last year and the boat has been kept dry - no musty smells or mould and I can leave all the cushions etc on it

To answer some of Fireball's comments -
  • It doesn't have castors
  • The Humidistat ( controls the amount of moisture ) works perfectly.
  • I place it on the Galley top so that if it does leak then the water drains into the sink
  • It has a bypass hose - which is positioned into the sink

From memory the running costs were around £15 per quarter in a MDL Marina

I've blocked up all of the external vents, a piece of perspex is taped over the louvres in the washboard, and I've also set up a timer switch so that it isn't running all the time - although as another post mentioned - I find that once the moisture content is down to the required level then it stays switched off anyway
 
Running costs in the region of £15 per quarter sound about right to me. We left ours running in a 27 foot yacht all winter the year before last and ran up a bill of around £40 over the entire winter - but that did include heating on a moderate number of weekends as well.

Last winter we spent a lot of time in the boat because we were working near the marina and used the boat as our flat during the week. We certainly ran up a larger bill, but still well under £100.
 
nigelmercier said:
There is a ECOAIR DD122FW MK5, is that what you have? Also see here.

What does it do if the power is interrupted?
Click to expand...

That's what we have, though it is badged "Meaco" - it is designed to restart following power restoration in exactly the same settings that it was running in when the power was cut.

I notice that Meaco are now describing it as obsolete and offering a lower consumption version. That DD122FW is the one that won the PBO Best Buy award in their comparative test a couple of years ago.

They are fairly noisy when running flat out. Doesn't cause us a problem - but the wife and I can sleep through almost anything. If you are a light sleeper and anticipate spending time on the boat with one turned on, it may be a problem.
 
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