AC Spitting Water

[DBG8492]

Exactly what the title says: The forward Cruisiar unit is spitting water.

This started about three weeks ago when it got hot here for a few days, and we had to run the AC for the first time. At the time, I thought it was that the drain line wasn't going downhill enough, and it wasn't draining the condensate effectively, allowing the fan to pull it up and spit it out. So, I pulled out the fridge and ran a new line pretty much straight down. For the next 24 hours, when we needed it, it didn't happen again. Then it got cool outside, and we haven't needed it again until now.

And of course, it's spitting again.

So before I go tearing into it and doing something stupid, I figured I'd ask here because when I look, it appears to be condensation forming on the inside of the squirrel cage where it butts up against the evaporator so now I'm wondering if it's a drainage problem or something else.

Any ideas? Because the way this thing is mounted, it seems pretty flat, and I think it would work better if the aft end were hiked up by an eighth or quarter of an inch or so. Doing that is going to be an all-day project, considering where it's mounted, and I don't want to do that if I don't have to.

 

[SIBERNUT]

Is there any restrictions in the intake air?
Could be a vacuum pulling condesate back up the drain.

 

[DBG8492]

Now that you mention it, we did install a couple of 9x9 inch intake filters - like regular household ones - because there were none there when we bought the boat.

I wonder if that's causing the problem... Never dawned on me that might be it.

We installed one on the aft cabin unit as well, though, and it's not doing it - but it's only a 10K BTU unit and the one in the saloon is 16K.

 

[O C Diver]

First, I would take a piece of 16 gauge multi strand flexible marine wire and use it as a fish through the drain hose to make sure it's clear.

On my boat I replaced all the AC units. The new pans were all angled towards the drain. The elevation from the corner opposite the drain was over an inch. Simply, you want the pan wet, but no standing water.

Also a good idea for clog prone AC units to use an AC pan tablet to kill biological growth.

Ted

 

[Comodave]

Ted suggested what I was going to say. Check for clogs in the drain route.

 

[DBG8492]

I should have added that when I said "ran a new line," I meant that I ran a whole new line and pulled the old one. It's definitely not clogged.

And to update, I pulled the new filter, and it hasn't done it again since. So we will see, I suppose.

 

[PhilPB]

When I installed my second ac unit, I put a "T" my old drain line to allow for the connection of the new ac drain line to also drain directly into my shower sump box. I had an issue with the condensate not draining from the new unit so I put a "T" into the line next to the drain pan of the second unit to serve as a vent. That solved my ac drain issue.

 

[bglad]

I have seen an AC leak when the duct wasn't well insulated. Condensation formed and leaked out the discharge register.

 

[MOJO]

I don't believe a 9" x 9" intake filter isn't large enough for 16K BTU system. One rule of thumb is to use a minimum of 200 sq inches of filter per ton of a/c. 16K BTU is 1.33 tons so the filter would be a minimum of ~266 sq inches or a 16" x 16" standard fiberglass filter. You can get a lot more complicated if you want. If you know the CFM of your fan (cubic feet per minutes of air flow), you can calculate the square area of the minimum required standard fiberglass filter by using the formula CFM/288 x 144. So, if your fan is rated at 500 cfm, that means you need a filter of at least 500/288 x 144 = 250 sq in. For a square filter, take the sq root of 250 which is 15.8 inches on a side. Round up to a 16" x 16" filter. Again, that's for a standard fiberglass filter. If you have a high MERV filter you need to size it up to handle the increased filteration and lower air flow efficiency of the filter.

 

[ValhowellPower]

I may be missing something. Is your issue with the condensate drain or the saltwater circulation system? If it is the saltwater system I have seen the suck cellophane into the intake and partially clog it. It could also be a clogged strainer. If it is the condensate tray, it could be a plugged intake with dust and crud or a clogged exhaust. It could also be a failingpump

 

[DBG8492]

I may be missing something. Is your issue with the condensate drain or the saltwater circulation system? If it is the saltwater system I have seen the suck cellophane into the intake and partially clog it. It could also be a clogged strainer. If it is the condensate tray, it could be a plugged intake with dust and crud or a clogged exhaust. It could also be a failingpump

It's condensation, and I think I've figured it out for the most part.

If there's any excess water in the pan, it will start to suck up into the fan. There's a point in time where you can tell it's about to happen - you can hear it slurping (for lack of a better word). I even think the fan suction itself may prevent it from draining effectively into the drain line.

On super-humid days, I have to make sure that the doors and windows are all tightly closed because that seems to cause the problem - which I suppose means it's drawing all that moist air into the house. Also, you can't run the fan on the highest setting - which is okay because the lowest setting is still pretty damned high.

I've been doing the doors and windows thing through 85+ degree humid days here, and it seems to be working fine. Today, the Admiral left the sliding hatch over the aft saloon door cracked about six inches, and it only took about 15 minutes before I heard the tell-tale slurping that always precedes the shower of water by about ten minutes.

So yeah - that's about it.

 

[Turtle Blues]

Mojo gave you good numbers. If you can find a way to increase the return air size you will also see an increase in efficiency and cooling capacity.