Condensation Drain on Dometic AC Unit

[oceancrosser]

Hello,

I have a DeFever 53 and would like to gently replace all the AC units on the boat. All (5) are reaching a mature age of 30 and they are noisy, and power hogs. They work, but my fear is when needed... they may not be there for me.

My first foray into this rabbit hole is replacing the unit in our salon. The current unit has the condensation line tapped directly into the base of the coils but the new unit I purchased (Dometic) just has a tap attached to the outer pan. Therefore, there will always be moisture sitting in the pan.

It this the NEW way of doing things? Are there alternatives? I am not excited about stagnate water either in my bilge or my stainless AC unit water pans.

What say you?

Thanks,

Rusty and Kris
M/V Kristine
DeFever 53 POC
Iuka, MS

 

[HeadMistress]

I eliminated the drain pan by re-routing the condensation drain line to a new thru-hull. Installed the new thru-hull just low enough to create a downhill run for the condensate.

 

[oceancrosser]

Hi Peggie,

Love your books and we have all but eliminated odors on our boat. Even after several weeks of un-occupancy, there are no residual smells.

Okay... not to sound completely like an idiot, how do you bypass the drain pan? There has to be a collection site and from what I see in the new unit, it all falls into the collection pan and then gravity feeds to the bilge (in my boat). I have heard of a product (tool) that uses the venturi effect to capture the condensate line by merging it with the water discharge, but that is for a later project.

Thanks for your help.

RB

 

[Comodave]

The venturi drain fittings are pretty finicky about any tiny debris in the water and then can clog. Personally I would skip them and just go with the drain built into the pan. You can mount the unit so the water will move towards the drain. Just don’t go overboard on tilting it, just a little should route the water to the drain.

 

[Bmarler]

Drain at the coils is still some sort of collection pan right? There will always be a wet collection point somewhere.if they route to the bilge I think I’d put in a collection box/sump like for a shower drain and pump it over from there.

 

[ranger58sb]

the new unit I purchased (Dometic) just has a tap attached to the outer pan. Therefore, there will always be moisture sitting in the pan.

Our pans are slightly tilted so condensation naturally flows into the drain lines... all of the drain lines slope downward... and then one of those is plumbed into a shower sump and the others are plumbed into a common drain for overboard discharge.

-Chris

 

[oceancrosser]

There is a collection pan on my older MarineAir, however there is a connection for the condensation line under the coils thus eliminating water stagnating in the pan.

My question is... is this the new age or new way of dispersing the condensation? Have it drip/drop into the pan and then allow gravity via a hose port the moisture overboard or to the shower sump pump.

What ever happened to a dry bilge (condensation pan) happy bilge?

I truly appreciate the comments and suggestions.

RB

 

[oceancrosser]

Hi Chris,

Thanks for sharing. I think my old age is having a difficulty accepting the new age way of dispersing the condensation.

I truly don't want to make a big deal of this issue, I am just trying to understand if I am missing something.

Thanks,

Rusty

 

[Comodave]

Mine drain into shower sump.

 

[Serene]

I just had two A/C units installed on my vessel and they also condensate into the pan and then drain to the shower sump, to be pumped overboard. This approach seems pretty standard when I was doing my research on which units to purchase.

 

[motion30]

I believe once The unit is turned off the drain PAN will completely drain as it has some built-in slope. Just like your home unit

 

[ranger58sb]

There is a collection pan on my older MarineAir, however there is a connection for the condensation line under the coils thus eliminating water stagnating in the pan.

My question is... is this the new age or new way of dispersing the condensation? Have it drip/drop into the pan and then allow gravity via a hose port the moisture overboard or to the shower sump pump.

What ever happened to a dry bilge (condensation pan) happy bilge?

Hi Chris,

Thanks for sharing. I think my old age is having a difficulty accepting the new age way of dispersing the condensation.

I truly don't want to make a big deal of this issue, I am just trying to understand if I am missing something.

I dunno... the system on our newer Dometic Turbos (DTGs) and the older Cruisair Stowaways on this boat and MarineAirrrrrr Vector Compact units on the previous boat... so going back to 2002 models... are all as I described.

I guess I'm not able to envision what's different about what you're describing in your older systems...

-Chris

 

[oceancrosser]

Thank you to all the gurus sharing age old wisdom and guidance.

On my 1986 vintage MarineAire unit, the condensate is captured directly from the base of the coils. There is a pan that captures any leakage or mishaps, however the paint is original and has never seen any moisture. But, I will admit I was a little surprised to see this new design having only experienced the older version.

The old unit is out and I am now learning about the wiring schematic with multiple units (AC) on one water pump. I assume (there you go with that word) there has to be some guidance on this.

Also, just to put to rest any fears that I am going to burn up my boat and any unsuspecting boat neighbors, I will have expert advice with anything electrical. I know several things about electricity... 1) can't see it. 2) can't smell it. 3) can't taste it. 4) but you sure as heck can FEEL IT!

Thanks again for everyone's help. I am looking forward to more learning.

RB

 

[HeadMistress]

Okay... not to sound completely like an idiot, how do you bypass the drain pan?

You aren't an idiot...It's been 25+ years since I had to deal with condensation drain on a boat...the air conditioners for my house are on the ground outside the house and drain directly on to the ground instead of into a pan. My geriatric brain forgot that the AC system on a boat has to have a drain pan...that it was the drain from it that I routed to a new thru-hull.

--Peggie

 

[oceancrosser]

Mission Complete,

Got the unit up and running yesterday with the help of our local HVAC guy at Aqua Yacht Harbor (a Safe Harbor Marina) in Iuka. He double checked my wiring to be sure I didn't cross wires or misplace them to a wrong feed.

Now... only 4 more units to replace over the next several months and I can begin the next project.

Thank you again to all for the gentle suggestions and helpful hints.

See you on the water.

Rusty

 

[Capt Ray]

Here is a link to the installation manual for the CTM models of A/C:

https://citimarinestore.com/en/index.php?controller=attachment&id_attachment=2755

This link with pictures shows the DIY replacement project for our salon A/C unit (16k BTU) a few months ago:
New A/C & Reverse Cycle unit project.

Both clearly show a hose for condensate drain. The CTM "tray" is a heavy duty FRP tray that is impressive, and a nice improvement over a painted steel unit on the original one pulled out.

Dometic and CTM share many of the same components, electronics, and controls, and both are common replacements for the Marine Air Systems units that seem to be in *everyone's* boat from that era.

I know that my forward A/C unit (still the boat's original Marine Air Systems) drains into the [recently replaced] shower/sink sump. I confess that I did not actually follow where the aft unit's condensate drain hose goes. I would guess to a through-hull fitting, but it *may* go to the bilge. ((I have major furniture to move to access the Starboard side engine room/bilge area. So, I only go there as-needed. I can do all my engine room checks from the more accessible Port Side.))

Personally, I would not be alarmed if the aft A/C condensate goes to our aft bilge.
I typically have 1" or so of standing water in the aft bilge from the slow drip of the stuffing box... even after new packing is replaced. This is very common in every inboard / shaft boat that I have ever owned. Part of my regular maintenance of this bilge is to hit it with some bilge soap followed by a good garden hose rinse. It is simply not a problem for smells or anything. "Yes, this bilge has a totally redundant bilge pump on its own circuit AND a high water alarm, just in case."

Note, that I should update our blog post, as I changed the thermostat from the one shown to the Passport I/O one (that looks like the old one). I could not get the fancy new one to get programmed to shut off the FAN when the condenser was not on... which has been our preference for years... for many reasons.

This tangentally related link about these A/C systems is, statistically, one of the most common producers of hits on our blog, as sent to us from Google:
Marine Air Systems error “HHH”

The high pressure switch discussed is available from my vendor:
CTM High-Pressure Switch For Marine A/C Units, Fits Dometic & Cruisair