Actual Experience with DIY A/C Condensate Venturi Pump ?

[batkins61]

I want to stop having the A/C condensation drain in the bilge and have basically two options: an electric drain pump with a new thru-hull, or a venturi type pump that works on the A/C cooling line (e.g. Mermaid Condensator).

I have seen many discussions about a DYI alternative to the very expensive Mermaid Condensator, including everything from a waterbed venturi pump to a casual mention of a Mazzei pump part number.

Has anyone successfully fabricated a venturi pump for this application? If so, I would really like to hear your experiences, pros, cons, and specifics.

My A/C is a Cruisair SXR16 with a PML500L seawater cooling pump. I figure the lift from the condensation pan to where the existing raw water outlet thru-hull is at about 2.5' to 3'.

Thanks!

[GeoPowers]

Originally Posted by batkins61

I want to stop having the A/C condensation drain in the bilge and have basically two options: an electric drain pump with a new thru-hull, or a venturi type pump that works on the A/C cooling line (e.g. Mermaid Condensator).

I have seen many discussions about a DYI alternative to the very expensive Mermaid Condensator, including everything from a waterbed venturi pump to a casual mention of a Mazzei pump part number.

Has anyone successfully fabricated a venturi pump for this application? If so, I would really like to hear your experiences, pros, cons, and specifics.

My A/C is a Cruisair SXR16 with a PML500L seawater cooling pump. I figure the lift from the condensation pan to where the existing raw water outlet thru-hull is at about 2.5' to 3'.

Thanks!

Hi Batkins61,

Have you considered using a shower sump with pump to an existing thru-hull? I looked at the Condensator, but didn't like the fact that it HAD to be installed above the waterline for safety reasons (something you only see in the installation manual, not on the sales sheet). I also didn't like the idea of using my bilge pump as the condensate pump (and having a damp bilge 24/7).

My solution was to install 2 shower sumps with integral pumps (I have a 2-zone system). For my Cruisair 16k unit up under the settee, I plumbed it from the drain to the sump, and then the sump pump to the refridgeration drain thru-hull. I put in as big of a loop as the space would allow (under the galley sink), and then tee'ed it off just after the pump for the fridge drain line. I also put in a check valve on the discharge side of the fridge pump before the tee to prevent condensate flowing into the fridge (highly unlikely, but worth the peace of mind).

An alternate, more elegant solution would be to simply plumb the drain for the fridge to the shower sump also and take out the other pump entirely. However, due to access issues with the fridge drain line I decided not to go that route.

I got the shower sump pump off ebay for about 75 bucks shipped, and the rest at WM. Total cost was probably about 85-90 bucks, a lot cheaper than a Condensator, and more "KISS". I'm guessing with our similar boats your set-up and costs would be similar.

Hope this helps-

Frank

[batkins61]

Thanks Frank! I'll look into that. Where/how did you mount the sump for the settee unit (the only one I have)?

[sfnz]

if you go to your local A/C refrigeration supplier you'll find little gizmos called condensate pumps, mostly these are fitted to the indoor end of a heat pump to remove the condensate while in cool mode, generally they also have their own mini sump with float switch and will pump to quite a head, as your A/C will be powered from either genset or mains power they are also a doddle to wire in, condensate can then be drained to pretty much anywhere you choose

[gettinthere]

Installed a venturi like this last spring:
Aquatic Eco-Systems: Aquarium Supplies - Turbo-Venturi® Injectors

Works fantastic. Sucks all the condensate out of the pan with no problems, except possible blockage from stuff in the pan. I put a piece of pantyhose over the end of the tube to keep out 'stuff' and clean that a few times a year. If the suction tube does block, all that happens is you go back to getting water in the bilge.

I also added a shut off valve downstream of the venturi, closed when we leave the dock.

It was much easier than I expected and works perfectly.

[GeoPowers]

Originally Posted by batkins61

Thanks Frank! I'll look into that. Where/how did you mount the sump for the settee unit (the only one I have)?

I mounted it about 12" to starboard of the compression post, kinda balancing a nice flat spot vs. being in the middle of the bilge. I cut two 2" strips from some synthetic white exterior trim board I had lying around from Lowe's, and stuck that onto the bilge with 3m 4200. Then I just screwed the shower sump into the two strips. Easy. I picked up some 12V from the bilge pump/float switch (using heat shrink connections), with an appropriate inline fuse.

As a bonus to this set-up your shower sump pump can act as a kind of auxiliary bilge pump in an emergency.

Frank

[batkins61]

Do you have any pictures of the setup? I'll have to see if I have enough space in that area. I'm also a little concerned that I don't have enough vertical space in the bilge to fit a sump. I haven't measured it, but it doesn't seem as much as most sumps are tall (plus mounting).

[batkins61]

Thanksd Getinthere, this is exactly what I was looking for. Did you use the 1/2" or 3/4" model? I have 5/8" tubing, so I have to go a little up or down. Where did you place the venturi, down by the unit or up closer to the thru-hull? I'm worried both about head and whether the suction will be enough to reach down from the thru-hull, so I'll probably need to balance. Did you see any appreciable reduction in discharge flow?

Thanks!

[capn_billl]

I went with the shower sump setup also. As I already had a shower sump, I just ran the AC drip pan line to an unused hole in the sump box.

[batkins61]

Originally Posted by capn_billl

I went with the shower sump setup also. As I already had a shower sump, I just ran the AC drip pan line to an unused hole in the sump box.

Unfortunately, that's not an option. I don't have a shower sump (water just pools on the shower floor until you push the button). I would have to put one in the bilge somewhere, and I don't have a lot of room under the floor boards, so it's likely to be a challenge to find something that will fit.

[S/V Illusion]

I used the old venturi tube from our son's waterbed for years with no problem. It was free (with the bed) but can be bought for $10 approx at any waterbed store. Simply tee into the water pump">raw water pump discharge line. I like the "no moving parts" aspect and it works as well or better than any other alternative.

[gettinthere]

Originally Posted by batkins61

Thanksd Getinthere, this is exactly what I was looking for. Did you use the 1/2" or 3/4" model? I have 5/8" tubing, so I have to go a little up or down. Where did you place the venturi, down by the unit or up closer to the thru-hull? I'm worried both about head and whether the suction will be enough to reach down from the thru-hull, so I'll probably need to balance. Did you see any appreciable reduction in discharge flow?

Thanks!

I think it is the 3/4". Better to go upsize so you don't restrict the flow of water.
It is plumbed in the discharge line after the A/C, about 2 feet of hose to the thru hull with a loop and a shut off valve. I would definitely NOT want it below static water line. Mine is about 2' above static water line but can get below water when heeling, hence the shutoff valve. I only run the A/C at the dock, we don't heal much there.

I don't notice any appreciable difference in water flow. It does disturb the flow a bit with the air injection, that changes the timber of the sound when the A/C flow hits the water. A bit higher pitch & quieter, which is a good thing.

[GeoPowers]

Sorry I didn't take any pics. Those Venturi tubes you guys are using are neat! I've never had 1st hand accounts of them actually working. Thanks for sharing.

Frank

[GeoPowers]

Originally Posted by batkins61

Do you have any pictures of the setup? I'll have to see if I have enough space in that area. I'm also a little concerned that I don't have enough vertical space in the bilge to fit a sump. I haven't measured it, but it doesn't seem as much as most sumps are tall (plus mounting).

I was cleaning the bilge today, and remembered you asked for a pic of my a/c sump/pump. Here it is in case you still needed it:

[batkins61]

Originally Posted by GeoPowers

I was cleaning the bilge today, and remembered you asked for a pic of my a/c sump/pump. Here it is in case you still needed it:

Thanks! What model/brand sump did you use?

I installed the venturi and it's working pretty well. I still need to create a dam/overflow at the existing drain in the condensation pan, and probably a check valve on the vacuum tube to avoid training it and the discharge line above the venturi into the pan when the pump stops. Since the bilge drain will still serve as an overflow, I may also put in a sump, if I can find one that fits.