HVAC not pumping water 2007 280EC

The Main Exchange

The HVAC unit has been working fine, turned it on yesterday and no water flow out the side of the boat. The compressor doesn't seem to be running either. The water pump only has 12 volts to it should be 110. Any ideas thanks in advance.
I bench tested the pump with 110v and it functions so I will reinstall tomorrow.

Michael T

@richardward2006. I've read many of your past posts and you're a savvy boater so I'm sure you'll have thought of many of my suggestions. Anyway, here goes with the first round of suggestions:

You have established that the pump is running and yes they are 110V units. 

You have set the thermostat to call for heat or cool. What should happen is the compressor should start running and call for the raw water pump (the 110v unit) to start supplying water. After a short period of time (a few minutes) if the compressor does not receive cooling water it will heat to the point that it will shut off. 

Obviously, if it is doing this the thermostat, compressor and 110v water pump are all working and you likely have an air lock or a leak allowing too much air into the system which fails to allow prime - hence no water exiting the through hull fitting. This would be my guess.

If the compressor will not come on when you activate the thermostat you may have a tripped breaker or bad ground (main panel or on the unit itself) or a loose connection of the thermostat wire on the printed circuit board. A remote thermostat sensor is plugged into the printed circuit board with an end like a telephone jack.

 If none of this makes any difference I'll look up some other ideas in my manual.

Good luck. 

The Main Exchange

@MT thanks for the suggestions, the compressor does not start hence no pump. I will go through grounds, reinstall the pump and check the breakers, thanks again.

Lifes Good

Check the codes.  There are codes that run the pump compressor at the same time or not as well as a bunch of other stuff like fan speed temp control and dehumidifier etc. Once the codes are set right.  Look in your manual for simple instructions.  Next if everything is running but no water flow.  Then it's an airlock.  Keep it simple. With system off take dock hose and run water pressure in the outlet outside.  This will force air out thru the bottom.  You may even hear the bubbles.  It's a simple way to reprime.  Keep it simple and check codes.  If the sytem gets a power surge or not shut down properly the computer gets cranky...

Mark
LG

Michael T

Richard, I have the manual for the Dometic/Marine Air A/C unit Model Passport I/O Compact&Legacy. I took a couple of pictures of the quick reference Code for settings. I hope this helps. I'll look for more trouble shooting info and post it too if I can find it....as I mentioned in the posts below you should be able to click on the pictures to enlarge and use your cursor to navigate. Good luck!

Dream_Inn

I had this problem once and I ended up blowing air reverse thru the water line on the AC unit (took hoses off, cause a garden hose didn't work).  I took line off of both sides of the unit, blew thru with my mouth (yeah, I know) and saw some dirt come out and that was it.  I had tried everything else first!

Michael T

Richard, I photographed the troubleshooting suggestion pages from the manual. You may have to click on them to enlarge and move your cursor around if you can't read them easily enough. They are good trouble shooting tips for any AC and hopefully will help you solve your issue. Good luck!.....Riuchard, I clicked on the picture and used my cursor to scroll down the page it works great. I'll look through the manual for any other tips that may apply to your issue.

Michael T

Richard I took two more pictures of pages from the manual. The first is an expanded code list for adjustments. the second is a wiring schematic for my model. Hopefully thy may be of some help and some correlation - at least I hope they provide some ideas....again, good luck! BTW , again clicking on the picture and using your cursor to scroll really helps.

Michael T

Clogged sea water strainer is another thing that can restrict the water flow enough to cause a failure to prime!

The Main Exchange

@MT thank you very much for the manual this will give me something to do tonight!!

rasbury

I have never had a problem with mine...have read other threads where problems came when boats were pulled, I trailer mine and thank goodness, never had a problem...looking for wood to knock on...

Michael T

@Rasbury I have had two problems, both of which were easy to fix. I had wonky temperature swings and all I had to do was change the location of the remote temperature sensor and that was fixed. The other main issue I had was loosing prime. particularly after cleaning a strainer and I added a water pressurization port and that issue is fixed. The only other very, very minor issue was when someone would fool around with the control pad and change operating codes but that too was easy to fix. These units are pretty good - knock on wood!

Michael T

....good luck Richard. Fingers crossed it's something simple, it often is! BTW not all of those codes in the manual apply to my unit. Some apply to the super fancy model. But you'll know if a code doesn't apply as zip will happen. Anyway the codes that don't apply are for real fancy features so you'll recognize that anyway!

The Main Exchange

Well good news! Reinstalled the pump, checked all the connections, replaced the water inlet hose, reset/programmed the controller and voila, its working. Thank you all for your help. This forum and its members are great!!  

Michael T

Way to go Richard. I know how frustrating some of the equipment can be when we have to eliminate more than one suspected fault! Yahoo!

The Main Exchange

Cheers MT you are a great help on here.

Dream_Inn

Great news!

raybo3

Glad everything worked out for you....

MarkB

richardward2006 said:

Well good news! Reinstalled the pump, checked all the connections, replaced the water inlet hose, reset/programmed the controller and voila, its working. Thank you all for your help. This forum and its members are great!!  

So what do you think was the problem. My guess is the system wasn't priming, and with no water flow, compressor wouldn't come on.

The Main Exchange

@MarkB, not sure Mark the pump would not run I think it was either a connection or the reprogramming of the controller that did the trick.

Michael T

I agree Richard.