Desiccant dehumidifier use with a plug in timer?

[Matt341]

Hi All,

I currently use a B&Q compressor type dehumidifier but have concerns about its efficiency during cold weather (a tube heater is used near to it at present but it's not ideal). After reading online reviews and looking at various websites, I purchased a Meaco DD8L Junior dehumidifier today to use on the boat over the Winter. While reading the instructions I came across the following warning/precaution - 11. Never unplug the power cord without pressing the "Power" key to off first, as this could damage the unit. Never unplug the dehumidifier before the fan has stopped blowing.

I don't want to leave the dehumidifier running permanently and what I have always done and plan to continue doing is to plug the dehumidifier into a timer which will be set for approx 6 hours running time every couple of days. I feel that it's overkill to run it permanently and it also won't help with the electric bill!

However, after reading the above point I contacted Meaco to see if my cause for concern was correct or not, I sent an email to both the sales department and technical help and the replies contained the following advice :-
1) You should never use an external timer with any of our units because you are then forcing the unit to switch off with going through its cooling down period and if you do this the unit will very quickly fail and the repair won’t be covered under the warranty.
2) It is possible to use it by using the auto restart feature to control the unit, but it may reduce the life of the unit.

The above point 1 was from the Tech help department and point 2 was from the sales department. . . . . . .

I now plan to take this back to the store and will either continue to use my B&Q compressor type which is happy to switch on and off at the mains or will purchase a different make desiccant dehumidifier if someone can advise one that will work with an external timer?

This is a bit disappointing as I particularly bought the Meaco due to it being advertised as suitable for unattended use in boats/caravans/holiday homes etc and able to resume operation after a power cut. I know they haven't directly mislead the buyer but it would have been really useful if they had mentioned that it was however not suitable for use with an external timer as I imagine quite a few of the above would plan on using it with a timer unless the electric supply is not metered.

Matt.

 

[Hadenough]

We have a DD8L and as livaboards in Britain have it switched on 24/7 over the winter. On its lowest setting it runs for maybe 15 mins in every hour. That is with two of us aboard cooking, breathing, making tea, etc. On an empty boat I doubt if it would run on average much more than 5, 10 mins an hour when it is damp and not at all a lot of the time.

 

[prv]

Presumably they all use the same technology, and so would all have the same issue? Even if they don't happen to mention it in the manual.

As it happens, the current PBO has a review of dehumidifiers; I didn't read it in detail because we don't have power in the yard and so can't use one, but I'm sure quite a few of them had built-in timers. That would avoid needing to use an external one to brutally cut the power.

On the other hand, don't all dehumidifiers have a humidistat? Would you not just set that to an acceptable level and then leave it up to the machine how often it needs to run to keep it there? How do you know that 6 hours every other day is enough to keep the humidity down?

Pete

 

[neil1967]

The Meaco DD8L will auto restart if the power goes off - it's one of the advantages of it. I'm not sure if the DD8L Junior is different. That's not to say it's a good idea to do it regularly, but I bought it to cope with the occasional power failure. However, I'm not convinced why you would want to use a time clock? The DD8L has 3 different humidity level settings - when the desired level is reached the dehumidifier turns its self off and then senses the humidity every 30 mins. If it goes up again it turns back on automatically, if not it does not. This must be better than setting an arbitrary time period for the unit to run?

Neil

 

[Vara]

My dessicant dehumidifier is left on all the time, winter and summer controlled only by its built in humidistat, power consumption seems to be fairly low, judging by my Leccy bills, and it is never on when I return to the boat after a time away, so I wouldn't bother with a timer.

The boat is pretty well sealed when we are away, no hatches or vents open. Would not have a boat now without a dehumidifier.

 

[johnalison]

I can't remember the make of ours. We used to use a rather clumsy one from B&Q but got a more compact replacement. The problem with it is that it has one of those fancy flush on/off switches that defaults to off if the power is interrupted. This scuppered my first attempt at using it with a timer. I have had to resort to leaving it at a high setting, 60 or 80%.

 

[Fox Morgan]

I have the Maeco junior.
I use it on low setting with humidistat. It's very low power consumption and by far, I mean BY FAR better than my old B&Q compressor dehumidifier.
It works on a cold boat. Which means it actually works. If I leave the boat unattended in the winter (I usually live aboard all the time but sometimes go away for a few days) with heater on frostat, the dehumidifier still works, even at 5 degrees.
the compressor type would be busy defrosting all the time causing power drain and not being very efficient at all at dehumidifying.
I just leave it be, let it switch on and off as needed. With a closed boat it will be working around an hour a day total and performs its own cool down and powers back up when needed.
Dont try to outsmart it with a timer. let the onboard gizmo do the job it was designed for. You wont be disappointed. (I don't work for Maeco, im just a satisfied customer)

 

[Bikerwookie]

We have the DD8L on permanently too. Its plumbed in and uses little power. It did however expire last week. Warning light flashing saying restricted airflow despite having a clean filter. First we knew was there was condensation in the morning on the deck head so they are effective. It has run for two years non stop so I went and bought another DD8L. Might go for the 5 year warranty this time.

 

[jwilson]

My dessicant dehumidifier is left on all the time, winter and summer controlled only by its built in humidistat, power consumption seems to be fairly low, judging by my Leccy bills, and it is never on when I return to the boat after a time away, so I wouldn't bother with a timer.

The boat is pretty well sealed when we are away, no hatches or vents open. Would not have a boat now without a dehumidifier.

+1
I use a DD8L, leave it on full setting for a day or three when the boat first comes out of the water (next week this year), then turn it down to a low setting and leave it running 24/7 through the winter with all vents sealed. I don't think it actually runs much when the boat is shut up, though when I go on board and open the companionway and let in damp air you can usually hear it fire up after a few minutes.

If the power goes off it will restart on whatever setting it was on, but this is not meant to be forced to happen daily with a timer.

The Meaco dessicants are the best I've ever found for winter boat use, been through an Ebac compressor-type (very very inefficient in low temps) XM "marine" one (also compressor - died days after the warranty ran out) and a B&Q own brand dessicant-type which worked well for 18 months then died. I now have three Meacos, two in house and one for boat. One did stop working, but supplier fixed even though just out of warranty.

 

[NDG]

Just leave it on all the time on a low setting, that's what we do. If you leave it switched off on a timer it's just going to work twice as hard when it switches on to remove all the dampness that's built up during the 'down period'. The difference in power consumption will be minimal.

 

[DipperToo]

I think that some of the desiccant dehumidifiers keep the fan running even when the correct humidity level is reached.

From the sound of some of the responses, there are also models that shut down completely and restart if needed. I read somewhere that other desiccant systems turn on at periodic intervals to 'check' the humidity levels and then turn off or enter the dehumidify cycle.

I just wish there was a simple comparison somewhere (the magazine articles do not always go into much detail).

I bought a premi-air unit and although it works, there is always a smell and black sooty deposits left on the headlining above the unit.

 

[Matt341]

Thanks Everyone,

My previous B&Q compressor unit had a dial on the top to adjust the humidity but it has never really worked, went set to normal it runs permanently. Hence why the requirement for a timer to control the running time.

I have tried the Meaco unit in my office with the humidity level set to the highest option, it ran for a couple of hours and collected roughly 2 cups of water before shutting down, around 30 mins later it started up on low for a minute or so and then switched off. My old unit never did this.

It seems to work a lot more efficiently than the other unit and also emits a small amount of heat which will reduce the need for a tube heater to be used in addition to it. I can see the problem of a timer cutting off occuring with any desiccant dehumidifier as I guess they all need to run through a cool down after use.

My only concern is whether it will run permanently on the boat unless it's very well sealed, there is a vent in the washboard and another mushroom type vent in the hatch above the saloon, would it be worth blocking these off? I'll give it a go on the boat next week and see exactly how much power it uses. Do others use it on the full fan setting or low fan?

Matt

 

[ditchcrawler]

I have a Meaco on my Moody31 during the winter.I first leave it on highest settings for a few days, then turn it down to the low setting and low fan for the rest of the time.The electricity cost is about £4 per month (excluding the standing charge).I block up my hatch vent and as many holes as practicable.I have a close fitting chopping board over the galley sink with a hole in it and I put the drain tube through this and tape round it.I bought the Meaco on recommendations from this forum.Pleased so far.

 

[Vara]

I bought a premi-air unit and although it works, there is always a smell and black sooty deposits left on the headlining above the unit.

Thats not right, neither the compressor or dessicant humidifiers i have had leave any deposits, a black deposit would indicate overheating on the recharge cycle, the dessicant one leaves a metallic tang to the air which i put down to the built in deioniser.

I would be very wary about continuing to use it.

 

[catlotion]

I have the Maeco junior.
I use it on low setting with humidistat. It's very low power consumption and by far, I mean BY FAR better than my old B&Q compressor dehumidifier.
It works on a cold boat. Which means it actually works. If I leave the boat unattended in the winter (I usually live aboard all the time but sometimes go away for a few days) with heater on frostat, the dehumidifier still works, even at 5 degrees.
the compressor type would be busy defrosting all the time causing power drain and not being very efficient at all at dehumidifying.
I just leave it be, let it switch on and off as needed. With a closed boat it will be working around an hour a day total and performs its own cool down and powers back up when needed.
Dont try to outsmart it with a timer. let the onboard gizmo do the job it was designed for. You wont be disappointed. (I don't work for Maeco, im just a satisfied customer)

+1
We've also got a Maeco dessicant dehumidifier and always used to leave it on when leaving the boat on a low setting (when we had the luxury of mains power). Very effective, and no need for an additional heater as the output temp is raised a bit by the dehumidifier. Almost too effective sometimes when using it when we were aboard, drying the air out a bit too much. Certainly made a huge difference to the boat interior!

Wish you could get a solar powered one! :-(

 

[DipperToo]

Thats not right, neither the compressor or dessicant humidifiers i have had leave any deposits, a black deposit would indicate overheating on the recharge cycle, the dessicant one leaves a metallic tang to the air which i put down to the built in deioniser.

I would be very wary about continuing to use it.

Took it off the boat last Spring - tried it at home - same results so off to the skip with it - out of warranty anyway.

Just ordered a Meaco DD8L based on comments here and online reviews. Loks like that is the one I was thinking about which sampled the air at periodic intervals and then shut down again if no action needed rather than running the fan continuously.

 

[Matt341]

Took it off the boat last Spring - tried it at home - same results so off to the skip with it - out of warranty anyway.

Just ordered a Meaco DD8L based on comments here and online reviews. Loks like that is the one I was thinking about which sampled the air at periodic intervals and then shut down again if no action needed rather than running the fan continuously.

Yes the DD8L junior definitely seems to switch off when the set humidity is reached, the fan runs on low for around 5 mins until it's cooled down and then it's silent with just the lights illuminated for approx 30 mins before starting up again to sample the air. Saw the DD8L junior at force 4 for £179, initially thought it was the normal DD8L (with ioniser) but on looking at the box it was a DD8L junior. Had a look in Maplins and it was £155 for the junior so it's worth shopping around first.

Matt

 

[CFarr]

Interesting thread, especially as I'm going into my first winter as a boat owner.
I do however seem to remember a thread about dehumidifiers and insurance?
I can't find it now but it did mention some units were not covered by insurance companies - found out by some unfortunate owners after losing their boats to fire.
I'm sure the ones sold by marine suppliers won't fall into this category, but possibly the B&Q, Aldi and Lidl brands could.

 

[Matt341]

Interesting thread, especially as I'm going into my first winter as a boat owner.
I do however seem to remember a thread about dehumidifiers and insurance?
I can't find it now but it did mention some units were not covered by insurance companies - found out by some unfortunate owners after losing their boats to fire.
I'm sure the ones sold by marine suppliers won't fall into this category, but possibly the B&Q, Aldi and Lidl brands could.

Good point, I have also heard something similar along these lines re the insurance companies. I have heard of a few incidents supposedly involving dehumidifiers. Will speak to the insurers this week!

 

[Noahsdad]

+1 DD8L Junior.
This will be the third winter for mine.
Great that it has a countdown timer so you can run it for a set period and it then shuts down. Very useful ifor drying wet oilies left on board.
Usually leave mine on all the time I'm not onboard in the winter. As others have said lowest settings with vents blocked, has a sniff of the air occasionally before deciding wether to fire up or not.
Great bit of kit, no damp anywhere on a 38.