AC issue

[gspaid]

We leave our boat at a slip where the temp in the summer stays between 50 (nights) and 90 (days). Freshwater. I set the AC temp controllers to @ 80 when I'm not there. When I got to my slip this past weekend I had a high pressure code. You can hear the AC unit (Condenser) kick in and fans blowing, but it cuts off after 30 seconds or so. I've git good water flow to the motor (through the strainer). The motor is not kicking in at all (there's a bit of rust on the motor housing, so I think it's just old and the magnet/coil is shot). I took it off and brought it home with me (I'm 180 miles away from the boat). Attached is a pic of the actual unit I pulled off.



It was working fine when I had the boat surveyed in May and for the first 4 trips this year. The complete motor unit is the PMA1000 and I see it for about $500.

It looks to be made up of 4 major parts:

1. FASCO 115v 50/60 2.1 amp 1/8 HP motor (3000 RPM)
2. Looks to be a solenoid attached to the motor
3. Cruisair (TaylorMade) pump rated at 985 GPH
4. Plastic pump housing

Questions:

• How can I test the motor at home to ensure that's the problem?
• Can I replace just the FASCO motor - all else looks to be in working order?
• Does anyone recommend something other than the OEM unit?

Thanks!

 

[mainstream]

If you are getting no flow after the pump this will cause high pressure you could ohm out the windings but if its original I'd just replace it if the motor won't run that is a start run capacitor that could be the problem it should have a uf rating on it they are less costly then the pump some times the capacitor will bulge if its no good. Pump won't run if star capacitor is no good.

 

[electricaldoctor]

I posted answer to a fresh water pump issue instead of AC pump issues. :smt021

 

[Greg]

Bypass the pressure switch if it won't start. If it starts, you will need a new switch.

Is there a pressure switch on the A/C pump?

 

[mainstream]

Looking at the pick there is just the line voltage and start run capacitor no flow switch the pressure error was from the refrigerant side of the a/c I believe due to no water flow causing high head pressure

 

[doozie]

it could be the trigger switch in the control panel. to test put a plug on the wires and plug it into a receptacle.

 

[Mike Blake]

Line dirty from the pump through the A/C unit?

 

[gerryb]

Get a multimeter with ohms reading and test the leads. If any go to ground, it is likely a bad motor. If all have resistance, then also check the capacitor to make sure it hits the right uF ratings.

 

[electricaldoctor]

Is there a pressure switch on the A/C pump?

No there is not. I originally answered as if it was a FW pump instead of an AC pump. Sorry for the confusion. Perhaps I should learn to read properly before I start typing. :smt021

 

[gspaid]

good question. I didn't check that. I just assumed that since the motor was completely silent that it was either a dead motor or the motor not getting a signal to run (electrical). In my experience, usually the motor will at least humm if it is trying to work through a clog. I'll check the lines though - easy enough. Thx

 

[gspaid]

will try that. Thx

 

[gspaid]

Thx gerryb. I didn't have an tester with me, but you suggestion is first on my list when I return to the boat. Thx.

 

[daddy d]

I would replace the pump with a new water cooled totally in-closed unit, your current unit is not worth repairing you want reliability

 

[gspaid]

great suggestion. Can you point me to it? I assume it only needs be 115v, minimally capable of the same flow (approx 1000 gph), and compatible with the input/output connections.

 

[skibum]

Is your boat having a mutiny? First its the head, next its the AC. lol...

Should be easy to test byconnecting the motor to an AC cord, and then hooking up a hose to the inlet with the other end in a bucket of water?

 

[electricaldoctor]

Too hot out to cheap out on a new pump. Don't overthink it. Hook up power to it, evaluate, have a sip of rum, bite the bullet, buy a new pump, move on and enjoy the rest of your boating season.

 

[gspaid]

I agree electricaldoctor! Looking for the replacement unit now.

 

[gspaid]

thanks skibum - I was so convinced it was the motor.... I just bench-tested it and it's NOT the motor. Something else is causing the motor not to kick-in. ideas?

 

[skibum]

I had a high pressure error on mine once while sitting at the dock. My Dometic manual said that the high pressure warning could happen if there was a lack of water flow. I took the water hose from the dock and stuck it in the hole that the water from the AC comes out of, and filled it up. It started working fine after that, and I have never seen the problem again. Not sure if it will fix your issue, but there might be some crud in the lines after the pump that you can clear out with the back pressure. Worth a try for a $0 fix...

 

[gspaid]

I'll could try that. But that doesn't explain the motor not kicking in when. the AC units blow but the motor doesn't kick so it gets no water and signals the high pressure reading. maybe a breaker somewhere or the actual controller not sending a signal to the motor?