AC System Failure - What are the Components?

[Papabrer]

Hi All,

1994 440 Express - I have two AC systems one for the v-berth and one for the salon. The v-berth system seems to work fine. When in watch the circuit panel it cycles between 10 amps, then 20 amps, then about 3-5 amps of power usage continuously during operation.

The salon system at the circuit panel seems to start out ok, then cycles to over 50 amps usage and the ckt breaker pops.

I do not know what the components are for the AC systems. If one of you smart guys/girls could give me some troubleshooting ideas I would really appreciate it.

 

[carterchapman]

So I just lost my bridge AC unit from basically the same symptoms. I tried a larger starting capacitor and blew the compressor - which was obviously locked up - thus the tripped breaker. I replaced mine with a Citimarine unit - it uses the same SMXii controller.

What size is your salon unit?

 

[dtfeld]

How old is the unit? If its older or original, your probably be money ahead to just replace the unit as the cost to get a HVAC guy out this time of year will likely get you a long way towards a new unit (assuming you/buddy can do the install).

If the unit is repairable, you could do that in the off season and sell to offset the cost.

 

[Papabrer]

Any ideas of where the unit will be located? Or what it would look like? I don't have an issue with repair/replace I just don't know what I am looking for?

 

[Blueone]

I don't have an issue with repair/replace I just don't know what I am looking for?

Careful....wait until you see the prices for new... It wont hurt to have it diagnosed by an AC guy there should be one local to you

 

[Papabrer]

So after more research - I believe I should have one compressor under the V-berth and another behind the couch in the salon. More to follow once I locate both of these.

I do have one question that I do need to clarify. Once the AC unit is cycled on at the control panel and the temp is set to turn on the AC, it kicks on the pump in the engine compartment. The question is should this pump be running continuously and should there be water exiting the boat at one of the through hulls continuously? Currently my pump is running but I cannot find and water exiting the boat? - thanks again, in advance I do appreciate the education you all provide.

 

[Blueone]

No …the water pump is triggered by the ac units coming on and off. If you have two zones then either ac unit can trigger the pump

 

[Papabrer]

Thanks understand that, can you advise about the water pump - should the water be cycling through the AC unit and then off the boat at a through hull fitting? Or does the water go someplace else?

 

[FootballFan]

Thanks understand that, can you advise about the water pump - should the water be cycling through the AC unit and then off the boat at a through hull fitting? Or does the water go someplace else?

Yes. You should see outflow from the overboard discharge.

 

[markrsimon]

The water pump will only run when one (or both) of your AC units is in the cooking stage. If the unit is on, with the fan blowing, but not trying to cool - then the water pump will not be running.

You most likely have one water pump, which feeds both units. There should be an above-the-waterline thru hull where the water exist - typically close by to where the AC unit is.

As to your issue - its most likely not related to water flow, as that type of issue generates a HP or high head pressure alarm. The ‘amps’ on the panel would be normal around 10amps.

If your unit is tripping a breaker, as mentioned above the compressor is most likely locked - and trying to pull max amps (LRA - locked rotor amps).

You can try turning that unit on, but deselecting cool. This will keep the compressor off, but atleast allow you to verify everything else - and have a fan blowing air around.

Then its either a bad capacitor or a locked up compressor. You should be able to swap capacitors - if they are the same or similar units.

 

[Papabrer]

Great information. I think I may have a couple issues going on.
First no water flow when the pump is running, I will investigate the pump system to correct this issue first.
Second the salon unit will try the capacitor swap and hope that it is not a locked compressor.
thanks again.

 

[Yendor]

. . . First no water flow when the pump is running, I will investigate the pump system to correct this issue first. . .

As much I don't like stating the obvious, have you made sure that the seacock is open and/or the strainer is clear, and/or the pickup is unobstructed?

 

[Papabrer]

Thanks for the common sense. Yes I have checked the seacock & strainer. Next I will check the lines with a bypass hose to see if I can focus on the pump itself for something else.

 

[Papabrer]

Finally got the time to tear into this problem.

Seacock - checks good functions properly

Hoses - great shape, no leaks

Raw Water Filter - was dirty but cleaned up well, gaskets replaced, all good

120v Water pump. - bad news here, looks like original equipment. Shaft spins freely when powered off, but locks up and motor hums when power applied. Can’t find anyone local that will repair.

Does anyone know make or model or specs for a replacement??

Any recommendations welcome

 

[markrsimon]

Confused a bit.. One of your AC units does work correct? and you see water coming out of the side of the boat, near that AC unit? or - do you have two pumps, one for each AC? Guessing you have one pump, and it works, given you said vberth AC works.

On my pump the shaft piece kinda floats in the motor, and needs water in there to float/spin.

That water pump itself also would not draw that much current (amps) even locked up.

Can you post pic of the water pump including the hoses in/out? Looking to see if the output side of the pump splits and feeds both AC units - or maybe splits somewhere upstream.

Did you find the thru hull for the salon unit? While you have the pump/hoses disconnected - put a garden hose up against that thru hull and push water back towards the pump - trying to flush that line. and/or if you have a splitter on the output of the pump- you can push water that way too.

 

[Papabrer]

Sorry for the confusion.

Single pump feeds both for and aft compressors. Single output on pump, must be a split somewhere up stream. Have already used garden hose in both directions, all flows good. Have one through hull in the bow and one in the transom.

I have one AC motor (see pictures) on the front of the motor is a magnet driven impeller that is attached to the motor shaft.

 

[b_arrington]

Sorry for the confusion.

Single pump feeds both for and aft compressors. Single output on pump, must be a split somewhere up stream. Have already used garden hose in both directions, all flows good. Have one through hull in the bow and one in the transom.

I have one AC motor (see pictures) on the front of the motor is a magnet driven impeller that is attached to the motor shaft.

Having one pump to service multiple units is pretty standard. I have one pump to service 3 AC units. It's sized for the proper flow, and distributes raw water through a manifold shortly after the pump.

A magnet driven impeller is normal as well for AC pumps. They will let water free flow through with a hose if the pump is off. That's also why AC pumps need to be primed; magnetic impellers can't self prime as an engine impeller can.

If your pump is toast, I would try to see if there are and GPM flow markings and then look up a replacement from something like Defender. If you can't, try to find the specs for a similar capacity AC unit and find a pump that matches (double for your two units).

 

[Papabrer]

Unfortunately there is no readable markings on the motor at all. I don’t have any clue about the OEM specifications

 

[b_arrington]

Unfortunately there is no readable markings on the motor at all. I don’t have any clue about the OEM specifications

Good thing the pumps are fairly generic. You just need to get one with the right GPM flow capacity.

 

[markrsimon]

I’m still confused - any maybe its just me - in which case I apologize in advance.

Q: so we are not getting any water flow from any AC thru hulls when the vberth AC unit is on?

Single water pump + working vberth AC unit = working water pump, with water existing at minimum 1 thru hull. otherwise the vberth unit would fault ‘high head pressure’ due to no water to keep it cool.

If vberth is truly calling for cooling (or heat), and you have a single pump - you should see water exit through 2 different thru hulls - when either AC unit is calling for cool (or heat).

Some piece of information here must be incorrect, or perhaps I interpreted something incorrectly.

When you backflushed water (hose against thruhull) did both thruhulls result in water coming out of the single line for the water pump - which would confirm an upstream splitter?