I believe the "VRX" models used the ECU Maxx control...Try this manual link to see if it helps (check the first page picture first to see if your control looks like it)

http://www.dometic.com/FileOrg.....U-Maxx.pdf 

Let me know,

Steve~

Most all A/C pumps have hard impellers & are not self priming if installed incorrectly...These type pumps draw less amperage and are much quieter & durable than a rubber blade impeller pump.

Changing the pump is not the answer...Finding why this one won't prime itself is.

If this pump is sucking air...Any new one will too...Aerated water is not a very good cooling medium, and that is what will be sent to the a/c, so it will work harder with aerated water.

Some things to look for in your plumbing....

• Look for a constant uphill run from thru-hull, to strainer, to pump...with no hose dips or loops.
• All three of the above must be mounted below the water line...No hose between should rise above the water line either.
• If you have the ...]]> Sun, 08 Aug 2010 07:35:55 -0500 http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p750 Maintenance http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p750 Steve,

  I have determined that the pump is indeed losing prime. The pump currently in th boat has a hard plastic impeller so I belive it may not be self priming. Can I use any pump of equal gal/min or does it have to be specifically for the A/C system. I looked at a couple at West Marine and they were self priming 20 - 30 gal/min at around $100-$130.

  Again I really appreciate all of your advice.

  Geoff

  ]]> Fri, 06 Aug 2010 20:20:52 -0500 http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p734 Maintenance http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p734 Geoff~

  There should be nothing but hose between the pump output & the A/C inlet....Your problem has to be in the plumbing, thru-hull, or the pump...Maybe sucking air and causing the pump to loose prime...The A/C unit is just shutting itself off as a protection.

  Shut everything off & look for leaks...These leaks will suck air when the pump is running...

  ]]> Wed, 04 Aug 2010 09:02:53 -0500 http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p733 Maintenance http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p733 Steve,

  Is there an internal automatic valve somewhere in the system after the pump. If not I will assume that the pump may be the culprit. Can I troubleshoot this by hooking the compressor up to shore water and running the ac that way to ber sure it is indeed the pump or a clog prior to the compressor? Is there any possibility of damaging the system by doing this?

  Thanks again, Geoff

  ]]> Wed, 04 Aug 2010 08:41:22 -0500 http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p731 Maintenance http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p731 The A/C will not run without water....True that is a Consistant...Or Constant....Either Way...No Water Flow...No A/C !

  I'm not there to see why you loose water flow, and really can't say from here...But one thing is for sure...You will consistantly loose A/C if you don't find your water problem.

  
  

  Steve~

  ]]> Wed, 04 Aug 2010 07:37:09 -0500 http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p728 Maintenance http://marine-ac.com/forum/maintenance/cruise-air-intermittent/#p728 Steve,

  We have a '75 Trojan F36 Tri Cabin. The cruise air has been working on and off. I cleaned the strainer and checked the pump and it seems to be working good, in fact the pressure out of the side of the boat was the best I have seen. The air worked for several hours and then the flow stopped. The pump was still running and the compressor was cycling on and off. This problem is very consistent in that after the system runs for a while the flow will stop and the compressor will cycle on and off.

  Any advise is appreciated.

  Geoff

  ]]> Tue, 03 Aug 2010 22:27:44 -0500 http://marine-ac.com/forum/maintenance/service-tech-says-i-need-a-new-unit/#p720 Maintenance http://marine-ac.com/forum/maintenance/service-tech-says-i-need-a-new-unit/#p720 The compressor can be replaced but not rebuilt...it's Hermetically sealed (welded together)

  A replacement compressor without labor is $660...Add labor & extra parts, and sometimes considering the shape of the whole condensing unit...It is better to just replace the whole thing...The warranty is better with a complete new unit, and you now have a new unit instead of an older repaired unit...Less chance of freon leaks because at least the new unit is tested at the factory and holding a charge when it reaches the customer....

  Leaks in the rest of the system are another thing, and I strongly suggest which ever route you go...Be sure your tech tests the rest of the system for leaks...Not that he wouldn't...But as I have said many times before...Running even slightly ...]]> Tue, 03 Aug 2010 12:08:16 -0500 http://marine-ac.com/forum/maintenance/service-tech-says-i-need-a-new-unit/#p651 Maintenance http://marine-ac.com/forum/maintenance/service-tech-says-i-need-a-new-unit/#p651 Thanks for your quick replay and I really appreciate your input. Is replacement the only option or can a unit be repaired?

  ]]> Mon, 26 Jul 2010 09:00:11 -0500