325 Carver Marine Air Passport II

[nazinteck]

Its been one of those seasons.

I purchased my 325 Carver in FEB 18. I immediately noticed upon acceptance what appeared to be an intermittent water flow problem while operating my two AC units. In the late spring I called for heat and in the summer it was strictly AC. I noticed some intermittent water flow stoppages during either operation. I have read that some units have relays working with the compressor to cycle on and off. I was never convinced my system was designed to do that. Most other Carver's in my marina seem to have constant water flow while the heat or AC system is on?

My two Passport II controls seem to work well. However I NO longer have water running through either unit and I do know my pump is not physically operating while wired into the system. When I located the Marine Air wiring junction box which appears to contain all the wiring for the two units, I noticed the previous owner had twist tied a "spare" 110V molded chord with exposed ends in what appears to have been an attempt to troubleshoot a pump? The spare chord was twist tied to the water pump 110v cable??? The surveyor apparently never noticed that? Anyway I suspect the pump is faulty and I will start troubleshooting the system this weekend as neither unit works right now but the controls do call for AC and both systems seem to initially fire up normally. Both units operate for about a minute and shut down as water is NOT pumping and I suspect that is what the system is looking for? I have removed the strainer basket and all is clear on the water line side. My plan is to start by disconnecting the pump wiring at the j-box and connect it to 110v to see if the pump works outside the controls. Any other suggestions are greatly appreciated.

[tomschauer]

check for 120 volts at the pump connections. If you have 120v and the pump isn't running, time for a new one. If you have voltage and the pump is running but no flow it may be air bound, or your condensers are clogged and will not allow water to flow.

[nazinteck]

Thanks. I'll check for voltage and report back.

[Midnightsun]

I noticed some intermittent water flow stoppages during either operation. I have read that some units have relays working with the compressor to cycle on and off.

This may be normal as my water pump works only when the demand for heat or cool is active. The air circulation fan is in continuous operation which is set to auto on mine. In other words, if I set the AC to 72F and the temperature drops to 72F, their is no more demand and the water pump shuts down. Once the temperature rises above the 72f set point, the pump will turn on.

As mentioned, check for voltage at the pump. To do so, make sure you set the AC down low so as to create a demand which will send 110v to the pump.

[nazinteck]

I checked the voltage for the pump on my circuit board last night and there is none. I disconnected the pump itself and wired it directly to AC and the pump works fine and I have great water flow through the thru-hulls. Now I suspect that there is no signal to turn the pump on via the "Logic"/ circuit board which operates the water pump for both units. I also called the previous owner last night and he identified that the water pump never turns off, so my assumption that there is NO relay device in my system that turns the pump off when the desired temp is reached is correct. My Carver manuals on the AC system are fairly detailed, but they really don't mention the circuit board connections. No part number references either. A quick view of the 'Marine Air,' now 'Dometic' manufacturer web site, is not very helpful either. My original operation manuals are also not very helpful on this circuit board either. I will try to reach out to Dometic today but welcome any other ideas. The replacement circuit board appears to be in the $300- $500 range. A circuit board malfunction makes much more sense as the problem has been intermittent all season. A pump problem would be either it works or it doesn't. Now I know the pump works. My system is comprised of a 16K (aft and salon) and 7K (fwd and head) Vector Rotary Series self-contained units with Passport II controls.

[tomschauer]

can you trace the 110 wire back from the pump? Maybe someone wired it direct to a breaker or a switch? A lot can happen in 20 years.

[Viper]

+1
if it hooks up to the control box as it should, check if you have output at the terminal block for the pump while the AC is turned on. If you don't, the function is controlled by either a relay or driver. If it's just that component that has failed and you're handy, you can probably source it at an electronic parts supplier if you pull a number off the part. These are usually located right above the terminal block where the connections are made. Relay pin configurations are universal and you should be able to find the pin layout and their function on line for testing purposes. The pin codes should be stamped or labeled on the relay.

[nazinteck]

Thanks and will continue to check power as advised. I am also confused as the com connector from the Passport II controller does not hook up to the Pump Relay Board as some other board schematics seem to call for. I have to trace the com connector too, but I believe each of my control boards get connected directly to the two AC units themselves. Can anyone confirm this is standard? There is no place on my PRB to connect them to anyway. They weren't connected to the PRB when I started my troubleshooting and the system did work earlier this year? I am beginning to suspect some work has been done in there. The Marine Air manuals call for either spade or loop connectors to the terminal board and mine were just stripped wires placed under the screw head. Not marine grade work. Plus I found that "spare" molded 110v chord with stripped wire ends twist tied to the pump too? I will continue with some voltage checks and report back. Thanks all

[tomschauer]

your wall controller should plug into J1 on the control board of the unit it is controlling. You should have a terminal strip on the control board with pump terminal l1 & L2, these should go to a rely box... somewhere. Probably near the unit closest to your a/c power panel.

[nazinteck]

Thanks for the help. I will follow the leads and hope to find exactly what you are describing in addition to doing some additional AC Voltage checks