• 224110040 $245.00 (2PRP) Two Unit Solid State Relay, 115V/230V 1phase

• 224110050 $275.00 (6PRP) Two To Six Unit Solid State Relay, 115V/230V 1phase

Cruisair Pump Relays and Triggers

• PR3X $285.00 Pump Relay, 115/230V, Up to 3 Triggers (not included)

• PR3X-2 $285.00 Pump Relay, 115/230V, with two 115V Triggers

• PR3X-2C $285.00 Pump Relay, 115/230V, with two 230V Triggers

• PR3X-3 $310.00 Pump Relay, 115/230V, with three 115V Triggers

• PR3X-3C $310.00 Pump Relay, 115/230V, with three 230V Triggers

• PR8X $275.00 Pump Relay, 115/230V, Up to 8 Triggers (not included)

• PR8X-4 $365.00 Pump Relay, 115/230V, with four 115V Triggers

• PR8X-4C $305.00 Pump Relay, 115/230V, with four 230V Triggers

• PR8X-5C $390.00 Pump Relay, 115/230V, with five 230V Triggers

• PR8X-6C $415.00 Pump Relay, 115/230V, with six 230V Triggers

• PR8X-7C $440.00 Pump Relay, 115/230V, with seven 230V Triggers

• TR115 $50.00 Relay Trigger, 115V

• TR230 $50.00 Relay Trigger, 230V

Note: Other repair parts are available…

Marine Air only offers a replacement board (which is everything needed but the box that houses it) no other parts are replaceable as they are all on the board itself.

Cruisair offers a replacement board & the seperate triac (the solid state relay) in addtion to the Triggers listed above.

• A-548 $40.00 Replacement To-3 Triac
• A-551 $75.00 Stud Triac Repl. Assy.
• A-552 $70.00 Relay P.C. Board PR3X, PR8X, PWX

First & Foremost are Filters…and not just the Sea Strainer I talked about in my last article….But the ones in the Return Air path too…

Direct Expansion A/C (as opposed to Chilled Water) systems rely heavily on good air flow to keep from icing up in the cool mode (Low pressure) or shutting off due to High pressure in the heating mode…

Generally speaking…Most boats may have two Return Air Filters per system or control…Some have more if there are more than one air handler on that system (compressor)

If you have a small cabin adjacent to another that the fan operates off the control in the other cabin (or just has a speed control installed in that small cabin) this may be one instance….

The trick to finding air handlers is to first look for the return air grill…

Once you have located the Return air Grill (also a likely spot for the first filter) it should be removed…Check if a filter is installed on the back side of the grill…If so remove it and set it aside…

Now with a flashlight…Look into that hole to see the path the air would take…At the end of that path should be the air handlers location…You may have to open another cabinet, or locker to gain access to that location, and boat builders can be very inventive in placing them in out of the way places…Ones that sometimes seem impossible to get to, but in most cases a panel can be removed for access…Here is where the second filter is located…On the aluminum fins of the evaporator coil…

All major manufacturers of marine A/C have shipped their units with a filter installed at the factory for some time now…If there is not one there…It has likely been removed after the system was installed…

I have serviced boats that the owners never knew of this factory installed filter…Or the air handler’s location for that matter…Thus when I removed the filter it looked like a piece of carpet…We all know Air does not flow thru carpet too well…

The manufactures install them there not knowing if a filter is going to be utilized in the grill at system installation…and If it is a clean path to the air handler (one that is not likely to get dust from another path) this filter can sometimes be discarded if it is tough to access, but it is better to have both in most cases…

In boats with multiple controls (more than one system) follow the above procedure till you have all the filters in hand…Take them out to the dock and have fun with the water hose…That is unless someone has installed the throw away fiberglass/paper filters, in which case I would recommend you replace them with some foam filter material that you might find at your marine A/C dealer…Or what Home Depot/Lowes etc…offers for home window A/C units.

Now either wait for them to dry…Or shake them out and re-install…A little water on them will not hurt a thing…

If you can get a good look at the aluminum fins…Check to see that they are not also clogged…If they are…That’s another story, and it’s probably time to call you’re A/C guy to clean them because he has access to cleaning solutions that work real well for this…and also likely has the equipment to do the job right…With less mess…

If you want to clean them yourself with a squirt bottle & garden hose…He may even sell you some cleaner, or you can try Home Depot…However what they offer never seems to work as well as what he gets from the wholesale A/C supply house…

Before you close the cabinet back up you should also check the condition/operation of the condensate drain…Especially after washing the coil…All that stuff that got washed off is now in the condensate pan and could have clogged the drain fitting/s or hose…

Best way to test this is with a quart or two of tap water…You can add some bleach/Lysol/whatever to kill bacteria…But first I would run some plain water into the drain pan to find out if the drain is clogged…This way you won’t have to suck out the bleach water to avoid it dripping onto surfaces when you remove the hose to blow it out…

Please Note: If you have to blow out the hose or fittings, and the only way you have to do so is by mouth…Try to find a clean piece of garden hose or the like to attach to the existing fitting or hose…These hoses are where bacteria like the Legionaires Virus live…You don’t want the old hose, or the condensate water to touch or enter your mouth!!!

Once you are done…We are ready to start up the system/s…

This is a good time for you to check the seawater pump & its pump relay operation (for boats with more than one A/C system supplied seawater by a single pump)

A seawater pump relay is a box connected to the pump that receives a signal from each separate unit…and then tells the pump to start pumping seawater when each, or any unit calls for it (starts to run)

They are easy to verify if they are working properly just by starting one system…Waiting for the compressor to come on…and then either looking over the side of the boat for water discharge, or if the pump actually runs by hearing it start…

Once you verify that that system started the pump…Switch the control off for that system…Wait for the pump to stop…Then follow the same procedure for each system by itself…You don’t want to run more than one system at a time for this test as it may be one of the other systems that brings the pump on…

If one of the systems does not bring the pump on…There is a problem with the pump relay box…Over the years there have been many kinds/models of pump relays, and to say how to troubleshoot each here would be kinda lengthy…However if you feel you have a problem, I will be happy to discuss your model/issue in the blog if you like…Otherwise you probably need to call Ole Faithful A/C Guy…

Now that we have verified Good seawater flow overboard and pump relay operation…We can run all systems…Do so for about half an hour….

Now we need to locate each compressor…

There are basically two kinds of direct expansion marine A/C systems.

• Self Contained units…sometimes called Stowaways or Cabin Mates…These are all in one units where the compressor, condenser, evaporator & blower are all on the same base…They are usually located behind the return air grille, and under a settee or in a closet…They are more like a window unit than central A/C…As the compressor is almost in the living space and thus you can get a bit more noise…Though now days the newer rotary compressors are pretty quiet.
• Split Systems…Sometimes called Remote…These are more like the central systems you may have at home…In that the compressor & condenser are “Remotely” located and connected to the Air handler/evaporator section by copper tubing to carry the refrigerant…These systems are quieter, and have more flexibility in that they can have more than one air handler/evaporator running off one compressor…and thus allow for installation in smaller cabinets, with smaller units, to reduce air noise even more…The total of air handler BTU just must pretty closely match the condensing units capacity….

Now that we have located the Compressor/s and they have run for a half hour…Be certain they are still running in cool mode…If not…Lower the temp setting of your control (t-stat)

Now locate the seawater condenser…It’s the tubes that horizontally (most are horizontal but some are vertical) wrap around the top of the compressor (condensing) unit…there should be at least two water hoses connected to it (some have 4) and with the palm of your hand…Grab the top coil….It should be Warm…but not Hot…

If it is Hot in more than one place…The unit is not performing as it should and is probably drawing more amperage than designed…

A couple of likely reasons…

• Seawater flow is not up to spec…Look for restrictions
• Seawater condenser is dirty…Needs to be flushed with an acid solution…Similar to the radiator in your car…At any rate…Not enough heat is being removed from the refrigerant…
• Not likely…But an overcharge of refrigerant…Maybe that last A/C guy didn’t do so good?…Or was it a buddy that said he knew what to do?
• Even less likely…Someone replaced the seawater pump with one that doesn’t have enough GPH pumping capacity for the system…Maybe somebody’s buddy was trying to save him a buck or two…You may laugh, but I’ve seen that happen too…Hey…He meant well!
• Most of the above reasons are probably best to call the A/C guy…Not the buddy…However you can & I will walk you thru flushing a coil to remove the scale that acts like a insulating blanket preventing proper heat transfer…Just at another time…

This next test is mostly for owners of Split/Remote systems…

Most of the newer Self Contained systems use what is called a Rotary compressor…Some of the older ones are still around that use the older reciprocating (piston) type…and to determine which you have is hard to explain if you have never seen either…But the Rotary type is usually slightly taller, and a lot skinnier than the Piston type…Have you got a Fat compressor matey?

Anyway…A piston type compressor that is too hot to touch on top…Is likely low on Freon…Rotary’s run Hot but Piston’s do not…

If either type is Cold or sweating…That’s another set of possibilities…

• Lack of air flow due to…Dirty filters or coils…Hey I thought we did that?
• Overcharge of refrigerant…That buddy again?
• Ductwork that is too small (or even crushed due to the space it was run thru) to properly handle the flow of air that the system BTU requires…We could blame…But let’s not…It won’t do any good anyway, and it’s gonna get too in depth here…Again we can discuss it in the blog for each individual circumstance…
• Last but not least…In a split system…Multiple Air handlers that don’t add up to compressor/condensing unit BTU…We won’t go into that here either….

This is getting a bit long…So in closing…I hope I have helped some…I look forward to answering any questions that I might…

Think of you’re A/C guy this New Years…I’m sure he thinks of you too…I know I do…

Steve~

Hi Mark…Don’t know if you are still watching this thread, or if you have seen my thread over in the “Introduce Yourself” forum but here’s my take…

It seems that when the system was flushed, that it was flushed just well enough to break loose some stuff…Now it is floating around in the hoses and randomly blocking flow where it now lodges from time to time…
Once the pump shuts off the water drains back, and with it the loose stuff moves…Only to lodge again maybe somewhere else when the pump starts again…

If the water flow does not look right to you (and you obviously have been watching it since new) then it is not right, and will continue to get worse…Changing the pump will not fix a thing unless the pump had a problem…It can only pump water thru unrestricted passages, and that water it can pump will re-direct to the un-restricted passages…Like said…Path of least resistance.

From descriptions here & in the thread I started…It seems the 459 has what I would call a odd or improper A/C plumbing/pump setup…

This happens sometimes with boat builders…Generally speaking…In my experience the only way to get them to make a change in a poor setup is for enough customers to have a problem and complain…No amount of prodding from us A/C guys ever seems to help in effecting that change…It’s a shame too because we are the ones dealing with this stuff everyday…They deal with building boats everyday…

So what is the fix ?…Well marine growth will always be a problem but there are a few things that can be done to help…

Over the years the A/C systems that boat builders install have gravitated to the Self Contained all in one units as opposed to the Split/Remote systems that most utilised for years…They don’t need guys with refrigerant certification to install or buy these All in One units…They are easier to install, and freon leaks in connections of copper tubing line runs are no longer something they need to worry about warrantying….All they have to do now is run power, water hoses from the pump, and duct…

The problem with this is the water runs are now much further than when the “Central” type systems were installed all in one location close to the pump…Back then we had very little growth problems (just scale buildup in condensers that was easy to remove) and flow was much easier to plan & maintain…

What I have found since this change is that the further, and or higher you pump seawater…The more problems you will have with growth, and it has also created the problems I describe below with using larger pumps…

Directing a pumps flow to units of varying distance & height for even flow to each…Is a challenge to say the least !
Generally their answer is to install an oversized pump in an attempt to brute force flow…

No I have not seen a 459 but it has been described as having two units on the bridge and 2 down below…I don’t care how they manifold this setup…It still going to be very hard to get the proper flow to each unit, and the least little restriction can and will upset any kind of balance they have designed into that system…The Pump has to overcome the height (Head) it needs to pump to the units on the bridge so it likely has been over sized just to do that with enough volume for those units…The remaining water can then supply the lower units…

Over sized pumps are never really the best answer over time (though it may be cheaper for them) because a over sized pump attempting to pump thru say four 5/8″ condensers (in this case) is (even when the system is clean) likely not pumping it’s rated flow which will cause it’s impeller to cavitate…This causes cavitation burns to the bronze impeller & pump housing…Thus causing premature pump head failure.

Again having not seen the install…My answer would be to install two pumps…One for the upper units, and one for the lower units…
They both could then be sized for the job presented, the systems & pumps would be much happier with less overall maintenance.

Steve~

The original poster had a March magnetic drive pump that would not pump water, and after the usual back flush & priming sugguestions he could still not get it to pump water…Just before I read the thread he had found that either something had gotten past the strainer (or he didn't have one) and had lodged between the impeller magnet and the pump housing stopping the impeller from turning, but not the motor from running…

Then the questions & discussion centered around how their systems reacted to loss of water flow and how & when their pump ran…Some of it was info that was a bit misleading for others depending on what type of system & control they have…So I posted these two posts below to try to help out…It's good info so why not share it here on my own site too ?

• My first post…

I'm glad the Chief Alen sorted out his pump problem but I thought I could add a bit of info to the thread…

If it is a single A/C system installed (not more than one compressor or control) there will be no need for a pump relay.

If it is a older Cruisair 3 knob type cabin control…Yes the pump will run with the fan and not cycle with the compressor unless it has been changed or is a newer digital control.

The thought back in those days was that when wired to the fan circuit…The owner could verify flow over the side before switching the system to run…They have since re-thought, and have changed that practice/wiring…

Yes it can also be wired to the compressor circuit so that it will cycle with the compressor…
It can be a simple change, but first you need to find where the pump wire runs to…Some run to the unit, and others are run to the terminal strip that should be within 3 feet of the cabin control….You then just remove the black pump wire from under the red terminal (Cruisair) and reconnect it along with the purple compressor wire…The pump should then cycle with the t-stat/compressor.

The other thing to watch for with the March Mag drive pumps is if they are run dry for very long…They will heat up enough to melt the plastic on the back side of the impeller around the ceramic shaft, and also the impeller mating surface of the plastic head itself…
The impeller may appear to rotate fine when the cover is removed but it won't when the pressure of the cover is against the impeller with the cover installed…If this is the case…The housing & impeller can be replaced, or you can also get the complete head without having to replace the whole pump.

Steve~

• Then another gentleman posted…

“I guess I must have the ideal system. If the water flow is disrupted on mine…the breaker trips.”

• My reply…

That is a good thing…But not actually a function of design of the A/C system or control.

I'll try to explain…

Most Marine A/C units with manual cabin controls have what is called a “Line Voltage” automatic reset high pressure switch (meaning it is actually carrying the compressor current) that trips around 425 psi, but then resets itself at around 325 psi…

Mermaid was one exception…They had/have a Manual reset Hi PS Switch with a push to reset button…Anyway…

Normal system operating high side pressure is somewhere between 200-250 psi depending on water flow & the temp of that seawater…

Also…In a Normal startup (system has been idle for a few minutes) the low & high side pressures will be equal (or very close)
This pressure will depend on ambient air temp but it will not ever be much over 196 psi (that's assuming a 100 degree cabin)and usually much lower.

The compressor has a fairly easy time getting rolling against that kind of pressure….But at where the pressure switch resets (325 psi) it has a much tougher time and thus draws much more amperage (than normal) in trying to re-start against that High pressure…Therefore tripping the breaker…

Units that didn't come with a start relay & capacitor have a harder time starting than ones that did come so equipped…

The ones that came equipped usually will start on lower dock power, and also may re-start at that 325 psi if the breaker is not closely matched to the size system it is powering…

Breakers are most often spec'd for wire size & distance to any given piece of equipment (under normal load conditions) for that equipment…The wire is also sized to be able to carry that projected load.

So you might see…There are trade offs…

Tripping that breaker weakens it a bit every time…Yeah I know…It shouldn't happen that often…And it does protect my A/C & Pump…

But having a unit that did not come with start components can mean the difference of being cool, or not being cool with marginal dock power (Like at a lot of backwoods marinas, and behind many homes) It can also mean a given unit may or may not start on a smaller gen set or inverter with other essentials running…

Tanqueray…I'm not saying your unit does or does not have start components…I'd have to know what you have to know that, but I can also say to everyone that a start kit can be added very easily to most all systems that don't have a relay & capacitor already installed if your situation warrants it…

The reason most manufacturers didn't use them was cost…I can also add that up until a few years ago Cruisair had them on all their units.

Note: The digital controls of Cruisair/Marine Air handle Hi/Ps much differently than manual controls….But that's another post…

Edit Note: Since the time of this original post, Dometic Cruisair/Marine Air has come out with a patented SmartStart that far out performs a standard hard start kit, or even a real start capacitor/relay…I should also add that I have personally installed them and they really do live up to the claims.  

We offer them in our store…Just click on the link below to see it, and it’s info…There is even a video…

http://marine-ac.com/2010/11/0…..-assist-2/

Steve~

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 controlled 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~