I started this site last year to “put my feelers out”  about what owners and captains may want to learn and share about marine  a/c.

The support has been more than I ever expected…

So… My New Year resolution to you is expand the site we created…Because of your feedback I am going to begin adding to my store to allow you to order most of the common Marine A/C system items that I found you’ve needed,  but until the store is fully operational…As always I’m here for you to contact…

Some important information…Sadly…Due to EPA regulations there will be no more R-22 systems/units produced in 2010…

• If you need to replace a R-22 condensing unit in an existing system…You will need to purchase a R-417A unit, evacuate your R-22 (which you would do anyway) and re-charge the system with R-417A (drop in replacement for R-22)…No need to change the air handler.
• For new installations (split system or self contained) the systems have been re-designed to operate with environmentally friendly R-410A which operates at much higher pressures that the existing R-22 or R-417A systems…These R-410A units can Not be paired with the older air handlers.

Your local A/C guy will know what to do & have the equipment to make the change.

Your comments & feedback are always welcome & appreciated…I need things to help me write…So ask away…It does stir the thoughts…

Clean Sea Strainers to All, and to All a Good Year…Think of the A/C/Heat/ Refer Guy…He Does You…

Steve~

Join the forum discussion on this post

We have touched on seawater cooling and lack of…Now what about if you have a intermittent problem, or the pump won’t start at all ?

In boats with multiple systems running on one seawater pump there is most likely a Pump Relay to receive a signal from each system to tell the pump it needs to run…That is unless it has been bypassed and the pump runs 24/7 from the breaker ( I see this done fairly often)

Lets start with the breaker in the main panel…Most are labeled A/C pump or similar…Some boats may have the pump breaker tied in with one of the A/C system breakers (Ocean Yachts for one used to connect the pump to the Main Salon A/C Breaker) but most should have a stand alone breaker…

The breaker feeds the pump relay and carries the load of the pump only…this power can be either 115 or 230 volts depending on the pump installed…

The individual systems aboard will then have their own breaker that powers/protects each A/C system & it’s wiring…These can also be 115 or 230v supplied…The reason I describe this is that some boats have a mixture of system voltages…Hatteras for example, always supplied one of the smaller systems as 115v and the rest as 230v…They would then install a 115v pump so that if all that is available on the dock is 115v, you can still have at least one cabin of A/C for crew/kids while the owners/parents go to the resort for the night without starting the generator (Well this has always been my assumption and nowadays most docks will have 230v anyway)

There have been many types of pump relays over the years…Some with mechanical relays (in previous times) but most for many years have been “ignition protected” solid state designs…Here are the most current & popular versions that I see, and a few of the most common failures…

Some were for built for only 2 systems and could not be expanded for more…Marine Air still makes a 2 unit relay (2PRP) but they also offer one that can handle up to 6 systems (6PRP) on one pump…you don’t have to utilise all if you have say 3 or 4 systems, and it actually gives you spare circuits to re-connect a system to if the one it’s connected to were to fail (that is if you have the 6PRP)…These relays are just a metal box with a single circuit board and all needed components on that board…Other than complete board replacement, there are no repair parts available/needed.

Cruisair went about it a bit differently…Years ago they offered one pump relay that could handle up to 8 systems on one pump (PR8X) and it came with individualised components, all of which could be replaced…The “Circuit Board” & separate” Triac” (solid state relay that switches & carries the pump current) came with the box…You could then add “Triggers” for as many units as needed, and you could also select trigger voltage (115 or 230) to match the system voltage feeding it….These triggers of course were/are replaceable with two screws & two plug on wires in the event of failure…

The only problem with this Pump Relay was the box was a bit large for smaller areas in boats that may only need 2 or three triggers…So they built a smaller box that can house all the same basic components (circuit board & triac) but only has room for up to 3 triggers…It can also be purchased with the triggers pre-installed for either 2 or 3 systems (PR3X-?) The question mark would be the number of triggers pre-installed (either 2 or 3)…They still offer the PR8X, and it can also now be purchased with triggers pre-installed but either box is not hard to add/install trigger/s in…

The main purpose of these relays is to run the pump when a system is calling for it…That means any system that is running a compressor (Some with just fan, IE: older Three knob cabin control-ed systems)…But if a trigger circuit in either type box fails (Marine Air, Cruisair, or any manufacturer) the pump may run for one or more systems…But not for the one that has the failed trigger circuit…

This sometimes causes confusion because if any one of the good triggers starts the pump…All systems that are connected to that pump will get seawater, and thus run normally….

However if the system/s with the good trigger/s cycle off, and the one with the bad trigger either continues to run, or starts up with the others off…It may/should shut down randomly with a fault code on the cabin display.

The easiest thing to do to verify if you have a problem is to test run each system” individually” to verify if you are pumping water with just that system running…If you find a system that won’t start the pump, the trigger circuit (in the pump relay) for that system has likely failed.

Also if the pump won’t run at all…These Pump Relays all have fuses installed either inside the box (Newer automotive type pull out fuse) or in a typical twist type fuse holder mounted thru the box ( It’s how Ocean Yachts gets away with running the pump on the salon breaker)…This should be one of the first things to check….If the fuse is blown, and then blows again after replacement, it’s time to look at the pump & associated wiring for shorts or bad/wet connections.

These Pumps & Relays are pretty easy to troubleshoot with a volt meter and a bit of common sense, but going into that here would be a bit long for all models…If you want help with your individual installation, I’ll be more that happy to answer in the forum troubleshooting section http://marine-ac.com/forum/troubleshooting/

Just let me know what you have and we can solve it there together…If you have another brand of equipment or model of pump relay, it’s likely that I have seen a few…We can figure those out together too…

Steve~

These two-stage systems use circulated water as a heat transfer medium. The warmed or cooled fluid is piped through a closed loop from the tempering unit in the engine room to any number of air handling units throughout the boat.

Dometic’s unique reverse-cycle design provides very efficient heating, even in relatively cold seawater temperatures, in many cases eliminating the need for separate heating systems.

Dometic offers a complete line of single-compressor and staged multi-compressor systems from 1.5 tons up, utilizing state-of-the-art compact modular tempering units.

We offer local Service & Sales here in the Tampa Bay / West Coast Florida area…

We also offer help on the forum http://marine-ac.com/forum/ with any troubles you might be having or not understand…Just drop us a line or two.Add New Post ‹ marine-ac.com — WordPress

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