Aircon Raw water pump sq58

[Tony W]

This pump seems to have stopped working and therefore no Aircon throughout. The system has 2 compressors that are fed by this single seawater pump and is a reverse cycle system. Anyone know where i can source one? The Fort Lauderdale MFR through me back??

 

[Hurricane]

If you can't source a new one, maybe you can find the pump curve from its brochure/manual.
The pump curve is a graph showing head up one axis plotted against flow across the other axis.
Simply put - as you restrict the flow of a pump, the pressure to overcome that restriction goes up.
The pump curve shows that relationship.

Then match the curve with an alternative pump.

A couple of years ago mine failed.
My situation is slightly different to yours because my pump feeds a DX system rather than a chilled water one but the concept is the same.
I was horrified at the cost of these pumps and, like you, I couldn't find a supplier.
So I went with an alternative - much cheaper option - a Stuart Turner pump at about one fifth of the cost.
I couldn't find any data of the design flow for the system so I just matched the design curve from the old pump to the Stuart Turner alternative.
It was a bit of an experiment.
In fact the Stuart Turner's pump is capable of slightly more flow than the original.
As soon as it worked, I bought another Stuart Turner pump.
That was 2 seasons ago - if I can get another season before changing to the spare, I will definitely be in pocket.

Some of these marine distribution networks are absolute "rip off" - Dometic is one.

 

[jfm]

That's a Scot pump. Nice machine. Available widely in UK/Europe. Not sure what country you want it in, but if UK then Nauticool in Poole have them, often in stock. Not cheap.

I always carry a spare, and a spare of its cousin that pumps the chilled water circuit.

 

[MapisM]

This pump seems to have stopped working

Before going for a replacement, I would open the cover of the small box attached under the label.
You should find a capacitor inside it, and there's a not so remote chance that you only need to replace that, instead of the whole pump.
Which means just a few quid, rather than several hundreds.

 

[Portofino]

Have you just simply turned it over a few times by hand ? There’s usually an end to get a tool ( socket etc ) on .

FWIW I run mine periodically in the winter , as with everything else just to keep it free .

Also a bit left of field ish with reverse cycle and so so temps , ie not that hot for the AC side to recognise it’s need to switch on the cooling compressor and not that cold for the reverse heating to realise it need to heat , then at this narrow place temp wise the pumps don’t immediately run , or stay off for what seems a long time while the ECU s figure out wether to activate the seawater cooling .

You can also possibly get the reverse switch in a muddle ,have it set the alternative way it really needs to be or maybe the valve stuck = needs a tap to free it .

For the motor I would rig up a independent 220/240 feed into it ( after turning and checking out all of the above ) to actually see if it’s 8uggered before key boarding and the costly unnecessary DHL parcel replacement arrives .

 

[Tony W]

Many thanks for the feedback, I’ve been looking into everyone’s points, The boats In Mallorca, Nauticool coming back to me with availability and cost. Price in Mallorca like for like is e2700 and an alternative e1560 which I’m waiting for the name of and will ask for your opinions. Capacitor has been ruled out as the pump works apparently but not enough to draw water?? I can’t access manuals regards the curves so will track down Stuart Turner position. too.

 

[jrudge]

I have just had this on my 58.

Mine was the impeller jammed with 15 years of crud. Just take it out, strip it, clean and re assemble. Mine then worked but the seal at the back which was dripping then failed.

I got another from boats.co.U.K. Same issue as mine. Cleared it. Back on boat al happy.

Given I had 2 with the same issue I would suggest that is yours also. The biggest issue is getting it out and removing the hoses.

Failing that any continuous duty pump of a similar size will work. Where in mallorca are you ?

Looking in detail at the picture to me that seems to be the chilled water pump not the raw water. Could be wrong but the raw water one is in is own recess.

 

[Hurricane]

Just had a very quick look at the Scot 35000 series pumps which look similar.
Curves are a bit strange but seem to run from 48 feet at zero flow to 90 GPM at 15 to 20 feet.
See the Scot curves here:-
Marine Straight Centrifugal Pumps
There are three curves in that range from 20GPM to 55GPM to 90GPM
Assuming US Gallons
Max pressure at zero flow is about the same for all the pumps in that range.

The Stuart Turner pump that I use is the CH 12-14 which has a max pressure at zero flow of 46 feet.
Max flow of the Stuart Turner CH 12-14 is 72 GPM
This is the Stuart Turner pump curve:-
https://www.stuart-turner.co.uk/contentfiles/Stuart-CH-Single-Stage-(50-Hz)-DS.pdf

A number of assumptions could be made here - 1st being "is that the correct range of Scot Pumps?"
Next assumption would be to find out which of the 3 Scot curves that pump actually is.
But, lets assume it is the biggest one (35070) the 90GPM one.

Incidentally, when I did the same exercise for mine, the curves to the original pump were smaller in both axis than the Stuart Turner pump.
Effectively making the Stuart Turner pump more powerful.
So my decision was easier.

But, in reality, a pump won't actually run at zero flow - there will always be something flowing.
Likewise, at the other end of the curve, the pump will always create a pressure at its max flow.
So, lets assume that the existing pump works at about 50GMP at 35 feet.
From its curves, the Stuart Turner pump can do 40GPM at 30 feet
IMO, that isn't much of a difference and the Stuart Turner pump would be fine.

The BIG difference though is the price - see here:-
Stuart Turner CH 12-14 Single Stage Pump - 46379
338 quid - they were only £250 when I bought mine.

That said, the quality isn't the same and Stuart Turner don't claim that it handles sea water.
Two things to consider - the impeller and the bearings.
But for that difference in price, you could consider the pump as a consumable.
And, as I say, my fist Stuart Turner pump is in its 3rd season.

BTW - I always have all the boat's sea cocks closed when I'm away from the boat.

Also a friend owns an older Squadron which has three Stuart Turner pumps running his A/C raw water.
He had one fail earlier this year so he bought a replacement.
After replacing the pump, he stripped down the old one to find a blockage so he now has a working spare!!

I'm not suggesting that this is the right thing to do - just that it is an alternative (cheaper) strategy.
You do have to keep spares though - and have it set up for a quick swap out when needed.
But that a lot of money to save.

 

[Portofino]

Take a look at Calpeda s site .
They do marine versions I have two , sea and chiller water .Very ubiquitous.
Not a lot of € ,£ etc .

 

[jrudge]

This is my pump.

Having a backup would be good. Google is not finding me much about its spec.

Hurricane you seem good at this !

I have 2 the same. One is sea water the other is chilled water circulation. From the op picture his one is the circulation pump given its location.

 

[Hurricane]

This is my pump.

Having a backup would be good. Google is not finding me much about its spec.

Hurricane you seem good at this !

I have 2 the same. One is sea water the other is chilled water circulation. From the op picture his one is the circulation pump given its location.

That label seems to mainly refer to the motor.
Do you have any more information on the pump that is bolted onto it.

Doing a quick search, you might be in a better position than I was.
In my case, I couldn't find a low cost replacement motor that would fit onto my old pump.
When looking up your motor, I came across a few websites where similar Century motors are available at very reasonable prices.
This one ISN'T the correct motor but might be an indication of the price of a replacement for yours.
1/3 hp 1725/1140 RPM 2-Spd 48 Frame 115V Belt Drive Blower Motor

Given that the motor is more likely to fail than the actual pump that is bolted on to it, it might be worth looking at spare motors.

And, if both your pumps use the same motor, it might be a good idea to have at least one a spare motor.

But, I love spares.

 

[MapisM]

After replacing the pump, he stripped down the old one to find a blockage

I'm a bit surprised to hear (also from jrudge, previously) of these raw water pumps blocked/fouled.
Non to mention circulation pumps, which are supposed to run only with clean fresh water and glycol.
I've got Calpeda pumps for both, almost 20yo by now, and neither give me reason to doubt that they can last another 20...
Don't you possibly have a strainer, upstream of the raw water pump? If not, I would highly recommend to fit one.
BTW, the strainer also allows an easy connection of a pipe from the boat fresh water circuit, which makes it dead easy to flush the whole raw water circuit - pump included, obviously.
Aside from the periods when I'm using AC regularly (i.e. a couple of months in the summer), there's zero salt water left in my chiller.
As well as anywhere else (genset, engines, shaft seals), of course.
BodgeFlow rules!

 

[MapisM]

Capacitor has been ruled out as the pump works apparently but not enough to draw water??

Hang on, what do you mean by "not enough", exactly?

If the pump motor runs but not as fast as it should, possibly getting unusually warm, that is actually a typical symptom of a defective running capacitor.
Beware, capacitors can fail in more ways than one, not necessarily impeding the motor to move at all.
You can positively rule out a capacitor only by checking it with an appropriate multimeter.
Missing that, it's easier to just replace the capacitor for peace of mind, since its cost is trivial.

One alternative, depending on your installation, may be air in the pipe upstream of the pump, because normally these pumps are not self-priming.
In a kosher installation, the raw water pump should be placed under the w/line, with the pipe running constantly uphill from the seacock to the strainer, and eventually to the pump.
But I came across boats whose chiller raw water intake needed to be primed after lifting the boat.

Lastly, if as jrudge envisaged your pump actually isn't for raw water but for the coolant liquid circulation, lack of cooling could also be due to a too low pressure inside the coolant loop.
Not sure about your system, but just for reference, Condaria suggests 1.5 bar.

 

[jrudge]

Hurricane. Thanks. I am off out now but will look more later.

Mapism. Mine was scale / marine growth. Over the years there is a bit and then a bit and then not used over winter and I suppose it just got too much.

Hydrochloric sorted it but the rear seal was leaking anyway and it then failed. There is no diy way to remove the impeller so I just borrowed another that had come of another boat for the same reason. Strip. Clear. All fine. Basically down to age. The manufacturers do say acid flush from time to time. I was tempted but haveing spent a day doubled up in the engine room was just pleased I had working ac

 

[Tony W]

From the op picture his one is the circulation pump given its location.

Looking in detail at the picture to me that seems to be the chilled water pump not the raw water

Berthed in Alcudia.
An engineer all things boats and in particular Volvo engines has done some investigation, there’s no raw water coming in and therefore non coming back out via the port exhaust. He’s took off hoses etc and forced fresh water through it. He seems convinced but have put benefit of your experiences and Hurricanes, Portofino and Mapism to him of which I’m awaiting response.
Age has to be a factor, as you know these things get some continuous hammer, I like the idea of a good de-gunge and certainly worth investigating more.

 

[Tony W]

That label seems to mainly refer to the motor.
Do you have any more information on the pump that is bolted onto it.

Doing a quick search, you might be in a better position than I was.
In my case, I couldn't find a low cost replacement motor that would fit onto my old pump.
When looking up your motor, I came across a few websites where similar Century motors are available at very reasonable prices.
This one ISN'T the correct motor but might be an indication of the price of a replacement for yours.
1/3 hp 1725/1140 RPM 2-Spd 48 Frame 115V Belt Drive Blower Motor

Given that the motor is more likely to fail than the actual pump that is bolted on to it, it might be worth looking at spare motors.

And, if both your pumps use the same motor, it might be a good idea to have at least one a spare motor.

But, I love spares.

I’ve got this picture, Ed Engel has been on the boat for last week doing his thing and had a root through manuals and found this.

Now albeit I’m practical your references regards curves etc are a little out my league. So, in your opinion does this answer any of your suggestions?

 

[Portofino]

Has you pulled the pipe off the raw water seacock ( should be a strainer ) and seen sea water flowing in ? What I am thinking so basic here the seacock s handle ( off ) has disconnected so even in the “ on “ position lined up with the flow Dir - the things closed = fits your description thus far .

 

[Portofino]

I’ve got this picture, Ed Engel has been on the boat for last week doing his thing and had a root through manuals and found this.
View attachment 157292View attachment 157292
Now albeit I’m practical your references regards curves etc are a little out my league. So, in your opinion does this answer any of your suggestions?

No need for any curves . Just copy the pipe dia , and it will define the pump size if you go down the replacement route .
Eg my Calpeda raw water pump has 1 inch pipage and it’s for a 42K BTU chiller unit .

This sits with your table ^^^ .

Anyhow start at the raw water seacock…pull a pipe off and eye ball water entering the boat .( testing bilge pump’s inadvertently )

 

[Tony W]

Has you pulled the pipe off the raw water seacock ( should be a strainer ) and seen sea water flowing in ? What I am thinking so basic here the seacock s handle ( off ) has disconnected so even in the “ on “ position lined up with the flow Dir - the things closed = fits your description thus far .

Well, Ed cleared the strainer when we first noticed Aircon wasn’t playing, and I’m sure Albert would have eased back the seacock with the lid off to check flow, but I’ll ask. Your correct to suggest it, he’s good and I’m sure knowing his thoroughness would have??

 

[Tony W]

Might just have to bite the bullet, keep the old, strip it down, put new capacitor in for the cost and keep as spare… if this thing has done 15 years I have to admit that’s fair game.