Air Conditioning condensing drain

[knockabout]

if u use the ac all the time reroute the drains into a shower sump and pump into a holding tank /enjoy your water maker

[redsky49]

Here is what I have done:

I have extended the two shower basin drains, along with the condensate drain for the AC, to a centrally mounted sump with integrated float and pump. This replaces a cobbled-up similar arrangement that I had assembled from plexiglass, copper window screening, etc. Happily, this one doesn't leak.

The discharge goes overboard via a vented loop. I also incorporated a foot valve (check valve) to prevent the water column up to the loop vent from draining back to the sump - visible on the far right edge of the pic.

This system, from Attwood, has been operating a couple years now.

[170122]

On new boats a small pump is installed on the drain discharge, Mini split orange pump, available in ebay,,, simple, clean and reliable.

Originally Posted by 98blackbell

Hello Cruisers Mel & Michelle here,

New owners of S/V Dream Catcher.

Our First time post. We bought a 2004 Catalina 42 MKII #885 at the end of May. This was a 2 year adventure to find the boat, story for another day. Bought it through a broker, Dunbar Sales in Brunswick GA at the Golden Isles Marina. They were a please to deal with. The boat spent it's whole life there, used frequently by its owner pleasure and racing. Last trip out mid May he won the race from Jax up to St Simons.

We solo sailed first timers up from St Simons to our home port of Savannah July 1st 2016. What a trip with the wife. Took 12 hours, all good. Boat performered flawlessly.

Now to our query? I want a dry bilge! How to do it running the a/c units?

We have 2 a/c units. Work great. Yes we are spoiled! Both units drain the condensating hoses into the bilge. As you know this rapidly fills the bilge with 4 inches of water, then the bilge pumps out the majority of the water. If we do not run the a/c units and dry out the bilge she is a dry boat.

What do you do with your drain lines? We have to have a/c in Savannah, 100 degrees with indexes over 110!

Currently the bilge holds more than 8 gallons, then the bilge pump turns on and pumps most but not all water.

The forward unit is under the settee seat, the aft one is in the engine compartment above the fuel tank.

I was thinking of using 2 condensatng pumps, #1 under the front a/c unit, run that hose out to #2 in the rear under aft a/c. Have the #2 in the rear pump it out of the boat some how. The condensating pumps will hold less than a half gallon each, plus what stays in the hoses. And have a dry clean bilge!

So,

What do you do?
Have you done this?
What have you seen that works?
What have you designed?

We want a dry boat!

Thanks in advance.

[sailjumanji]

Originally Posted by SVNeko

Have any of you fit the venturi below the waterline? Even if above, if your AC is below the waterline, do you worry about a siphon from the seawater line into the pan?

Never happens. AC pan is below water line. The condensator is installed very near the above water thru hull that is the AC water pump discharge. I think path of least resistance is the large diameter tube and then to open thru hull. Siphoning would have to happen in an upstream direction.

[SVNeko]

Originally Posted by sailjumanji

Never happens. AC pan is below water line. The condensator is installed very near the above water thru hull that is the AC water pump discharge. I think path of least resistance is the large diameter tube and then to open thru hull. Siphoning would have to happen in an upstream direction.

Thanks for that. I am trying to picture it. Water will siphon upstream if the end point is lower than the starting point (ie, the waterline). I am thinking there must be some kind of siphon break in it. Maybe the cooling water system does that.

[transmitterdan]

A Venturi device is not a siphon. It works on the principle that a slight vacuum is created as the water passes over the small opening in the tee. This difference in pressure "sucks" the water out of the pan. It cannot lift the water very high so it may seem to act like a siphon but it isn't. I doubt it can lift water from below the water line.

The Venturi device is supposed to be installed above the water line in the outlet side of the A/C coolant hose. Thus when the A/C is not running there is no water in that part of the system as it drains overboard. So no chance to get sea water back into the pan.

[sailjumanji]

Originally Posted by transmitterdan

A Venturi device is not a siphon. It works on the principle that a slight vacuum is created as the water passes over the small opening in the tee. This difference in pressure "sucks" the water out of the pan. It cannot lift the water very high so it may seem to act like a siphon but it isn't. I doubt it can lift water from below the water line.

The Venturi device is supposed to be installed above the water line in the outlet side of the A/C coolant hose. Thus when the A/C is not running there is no water in that part of the system as it drains overboard. So no chance to get sea water back into the pan.

This is a good explanation, although I disagree with the reference to not being able to lift from below the waterline. Think about it - the condensator sucks water out of an open A/C pan. There are no waterline forces on the pan. You should probably refer to the condensator manual to see if there is a lift limit, but in my installation, the A/C pan is probably 6 inches below the waterline and the condensator is about 2.5 feet above the waterline. So its lifting three feet.

[hsi88]

With fresh water always in short supply, why not filter and use. Even if only used for rinsing after swimming or washing clothes, why let it go. Although the condenser will have some bacteria, it starts out as distilled water and is about as fresh as you are going to get. There are plenty of good filters on the market that are not all that expensive. Way cheaper than a water maker. Of course if you are only using AC at the dock, you will already have a source of fresh water.

[SVNeko]

Originally Posted by transmitterdan

A Venturi device is not a siphon. It works on the principle that a slight vacuum is created as the water passes over the small opening in the tee. This difference in pressure "sucks" the water out of the pan. It cannot lift the water very high so it may seem to act like a siphon but it isn't. I doubt it can lift water from below the water line.

The Venturi device is supposed to be installed above the water line in the outlet side of the A/C coolant hose. Thus when the A/C is not running there is no water in that part of the system as it drains overboard. So no chance to get sea water back into the pan.

I understand how a venturi works. The issue is not about siphoning while it is operating, but rather when it is off and you have a seawater intake plumbed to a below-the-waterline AC condensate pan. Just like a head, I would imagine a siphon break would be needed to prevent back siphoning of seawater into the pan. I don't believe AC seawater lines drain when not in use. I could be wrong but this is what my tech told me.

[a64pilot]

Good point, while I think the line size is too small to constitute a sinking hazard from a siphon, I certainly don't want salt water all in my AC condensate pan for sure

[transmitterdan]

Originally Posted by SVNeko

I understand how a venturi works. The issue is not about siphoning while it is operating, but rather when it is off and you have a seawater intake plumbed to a below-the-waterline AC condensate pan. Just like a head, I would imagine a siphon break would be needed to prevent back siphoning of seawater into the pan. I don't believe AC seawater lines drain when not in use. I could be wrong but this is what my tech told me.

The Venturi device has to be above the water line because the A/C coolant outlet is above the waterline too. This there is not much risk of back siphoning.

[SVNeko]

Originally Posted by transmitterdan

The Venturi device has to be above the water line because the A/C coolant outlet is above the waterline too. This there is not much risk of back siphoning.

Why does having the cooling water outlet above the waterline mean the Venturi has to be above the waterline? Seems to me all it needs is flow to operate. When not operating, yes, it's possible that the above-waterline outlet may act as a siphon break, so long as the pump does not act as a seal, which I don't think is the case. Then will it let the water in the line run into the pan until the air gets there? If the ac and Venturi are above the waterline, then I see no issues, but ours is below.


Sent from my iPad using Cruisers Sailing Forum

[transmitterdan]

Because if it is below the water line then it might backflow when the A/C is not running. To prevent that they recommend installing in the A/C discharge line which is always above the water line. So it has no water in it when not pumping.

[Pelagic]

Originally Posted by transmitterdan

Because if it is below the water line then it might backflow when the A/C is not running. To prevent that they recommend installing in the A/C discharge line which is always above the water line. So it has no water in it when not pumping.

This is what concerns me about the venturi solution in a sailboat that can heel dramatically.....
Most A/C cooling discharge outlets are at the waterline, but that system is closed, unless you introduce a venturi drain.

I prefer large drain hoses ( easily removable for cleaning out the gunk)....that gravity drain to a pump out sump.

[ronbo1]

I use a Whale sump pump kit which replaces the smelly, problematic shower sump. You can feed waste water from shower, AC, refrigeration condensate, etc. to it. Fully enclosed, its activated when it senses water.


Whale Grey IC Shower Waste Pump Kit

Ronbo