Help Aircon Dometic question.

[oceandrive]

I have fitted to the boat Predator 92s based in Balearics a Dometic air con system, the boat has two chillers / heaters and 13 handlers so "chilled water system". the system has a dehumidifier option so that during the winter the handlers will work as Dehumidifiers.

My question is do I need to run chillers or Heaters or just the handlers. local agents just looked blank when I asked them using my best Spangalish which is not too good.


Also the forward handler in the saloon can run as a windscreen heater but I have lost the detail on how to program this. I know I have to put the chillers into heat mode for this.

Can any forumites who may run a similar system or work with such systems help please.

 

[aquatom]

Yes the chillers will need to be on cold. One chiller should be enough.

Where will the condensate water from the air handlers be going? If it is running into sump boxes then thease will need to be on also it is surprising how much water they produce!

 

[PaulGooch]

Any aircon system works as a dehumidifier, any time it's switched on, provided the water it makes is removed. Your car aircon system does this, which is why cars with regularly used aircon, or those with climate control, don't suffer as much with misted up windows in the Winter. The evaporator/chill/bit that gets cold frosts up as it gets cold. As the system cycles, it frosts up then defrosts, frosts up, defrosts. If the defrosted water is removed, the air inside of the boat/car/house contains less water.

 

[jfm]

I have fitted to the boat Predator 92s based in Balearics a Dometic air con system, the boat has two chillers / heaters and 13 handlers so "chilled water system". the system has a dehumidifier option so that during the winter the handlers will work as Dehumidifiers.

My question is do I need to run chillers or Heaters or just the handlers. local agents just looked blank when I asked them using my best Spangalish which is not too good.


Also the forward handler in the saloon can run as a windscreen heater but I have lost the detail on how to program this. I know I have to put the chillers into heat mode for this.

Can any forumites who may run a similar system or work with such systems help please.

I have the same system on last and next boats. A few points here:

1. To run in dehumid mode you have to run the chillers running in cool mode. Or just one chiller, if you're happy with less power. Running the handlers with no chillers is pointless and wont achieve anything

2. To run the screen demist you have to put the chillers into heat mode. Then all the handlers will get hot water and act as heaters if turned on. There must be a switch somewhere to select heat mode on the chillers. Then to operate demist wait for the heat LED to light up on the left side of the Passport air handler control (the thing with red LED numerals) and when that is lit just dial in 25degrees or something and run the fan and you'll have demist warm air from that handler

BTW, FWIW I never use mine in dehumid mode. To get any benefit from dehumid you need the boat dehumidifed all winter. But it's crazy to run these systems all winter. The energy burn is massive and the wear on the components is big and expensive. And they're not the world's best dehumidifiers anyway. I much prefer to buy a few freestanding dehumid units and plug them in on the boat and leave the airco system turned off. It doesn't matter if the freestanding dehumid units wear out cos they only cost €150 to begin with. I have and would strongly recommend this one - it gets top reviews and works really well. I'll be getting three of these for the sq78 next winter.

 

[oceandrive]

Thanks guy and a special big thanks to JFM hope the builds going well. We have a couple of 78s in Mahon they look nice boats.

 

[jfm]

Thanks guy and a special big thanks to JFM hope the builds going well. We have a couple of 78s in Mahon they look nice boats.

Build going well thanks OD. Lorry is booked to take it from factory to sea on 2/12/10. You have the kiddie-proofed 78 there called, er, Macho Man, which is for sale, but is there another? I'll be there next summer so long as the matriculation police don't scare everyone away!

 

[Hurricane]

I have the same system on last and next boats. A few points here:

1. To run in dehumid mode you have to run the chillers running in cool mode. Or just one chiller, if you're happy with less power. Running the handlers with no chillers is pointless and wont achieve anything

2. To run the screen demist you have to put the chillers into heat mode. Then all the handlers will get hot water and act as heaters if turned on. There must be a switch somewhere to select heat mode on the chillers. Then to operate demist wait for the heat LED to light up on the left side of the Passport air handler control (the thing with red LED numerals) and when that is lit just dial in 25degrees or something and run the fan and you'll have demist warm air from that handler

BTW, FWIW I never use mine in dehumid mode. To get any benefit from dehumid you need the boat dehumidifed all winter. But it's crazy to run these systems all winter. The energy burn is massive and the wear on the components is big and expensive. And they're not the world's best dehumidifiers anyway. I much prefer to buy a few freestanding dehumid units and plug them in on the boat and leave the airco system turned off. It doesn't matter if the freestanding dehumid units wear out cos they only cost €150 to begin with. I have and would strongly recommend this one - it gets top reviews and works really well. I'll be getting three of these for the sq78 next winter.

Thanks for this, jfm

To date, I've been using the main saloon A/C system in its dehumidify mode but always thought that it a bit like taking a sledge hammer to crack a nut and the wear and tear could be unnecessary. I use the saloon A/C unit (although I could use the dinette one) because the condense naturally drains overboard – the lower deck units drain into a sump and are pumped away. I always like to leave the boat with ALL the DC switched off so that if the boat were to loose shore power, my batteries wouldn’t be drained. The pumps for the lower deck’s sumps are DC powered so wouldn’t pump any condense out.

Thanks for the link – when we had our old boat on the Hamble, I used one of those cheap compressor dehumidifiers and I’m not sure how safe they are when left alone so, to date I’ve resisted using one on the Princess. The units in your link look much safer – I’ll order one today and check it out – probably take it to the boat next visit.

Thanks