Refrigeration System Water Pumps

[Stargazer3]

Has anybody out there replaced their refrigeration system water pump? What did you buy? My dealer replaced mine with the same kind of pump I use for water pressure or wash-down. It's noisier than hell and I HATE it! I tried to shop for a replacement - but nobody tells you how noisy a particular pump can be. Help! Capt Bill on STARGAZER

 

[RichH]

I may not be reading your post correctly .....

First, most refrigeration systems use a *continuous duty*, centrifugal pump for their cooling needs. Centrifugal pumps are usually VERY quiet. 12vdc centrifugal pumps used on boats are usually low head pressure, high volume flow ... a 'few' psi maximum output.

Pressure water system pumps on boats are usually wobble plate/diaphragm pumps (the noisier than hell pumps) and are not *continuous duty* rated, but do usually have a thermal cut-off switch to shut down the pump when it becomes HOT from running too long (usually more than 15-20 minutes). Such pumps are relatively low flow, high (30 psi) pressure.

If I read your post correctly, your 'dealer' installed a low flow, (relatively) high pressure, (usually) non continuous duty, water system pump on a system that typically has a moderate flow, low pressure, *continuous duty* pump. I'd say that this is a total mismatch of pump applications which puts you at risk of pump burn out in a relatively short time .... and that doesnt include the 'noise' generated by a 'diaphragm type' water system *pressure* pump.


If your refrig. is water only cooled and this *pressure* pump shuts down because of thermal overload on the cooling pump .... your entire refrig. system will fail.
Id question your 'dealer' about this mismatch, and get a written guarantee from him/her that this pump will have its 'warrantee' honored by him/her due to the 'dealers' choice of application. In simple-speak: if this *pressure* pump fails in a short time, the dealer remains responsible, including time/labor charges for rip-out and reinstall with the correct pump for such an application.

BTW - the most common 'refrigeration cooling pumps' on rec. boats are probably the 12vdc, magnetically coupled impeller, *continuous duty*, centrifugal pumps by MARCH Corp. These are VERY quite running pumps. example: http://www.marchpump.com/series-893/

 

[Stargazer3]

Thanks, Rich! You gave me exactly the information I needed to fix this noise problem!

 

[FastOlson]

Perhaps a Plan B ?

Those little coolant pumps for fridge heat exchangers are usually quite expensive. And then there's the worry of the intake clogging when ignored for a while.

If you have a haulout coming up, it might be time to reformat the fridge system with a 'keel cooler' and eliminate a lot of complexity. Save you some measurable amps, too.

I installed a complete Frigoboat system with the 'keel cooler' heat exchanger in '02. Still working without a hiccup. Our entire house bank is only two GC batteries.

Simple and Efficient.
(Heck, my wife probably wishes she could say that about me!)


Loren

 

[RichH]

Thanks, Rich! You gave me exactly the information I needed to fix this noise problem!

Well not quite.
You have to, or have 'an engineer', calculate all the pressure drop losses and the total 'net positive suction head' and total 'elevation' for the pumping system ... and THEN insure that the pump will be able to deliver the correct 'flow' to the refrig. heat exchanger pipe.
What Id suggest is you make a careful drawing which includes all the inside dia. pipe sizes, strainer (with model number and in/out diameter), number of elbows, total run of 'plastic pipe' including inside diameter, the elevation of the installed pump above or below the boat's static waterline, the elevation of the highest point of the refrig. cooling water piping .. including the inside diameter of the exit hose, type and size of through hull at the exit, etc. .... a complete 'technical' drawing with sidebar list of all the components .... and simply call and then send the dwg. to the *application engineering department* of *March Pump Corporation (marine division), etc. and let them make a 'pump selection' for you. A phone contact first, would be needed.
Of course if you have a favorite close-by 'mechanical or chemical engineer', they'd be the best to size the pump.

Yup, you dont want a non-continuous duty *pressure water pump* with a DIAPHRAGM if you dont want a LOT of noise and vibration ... not even mounted on 'rubber'.

good luck.

Ahem & BTW .... I'd select another 'dealer' to do the 'serious stuff'.

 

[Brian147]

I just changed mine on a water chilled Polar Mate refrigerator with a March 893-09. This is the same pump that Adler Barbour uses. Be sure to get the brushless model that will last for 40,000 plus hours. The pumps with brushes burn out in a year or two and are rated for 3,000 hours. Google the model #, several places sell them. I bought mine from Tesco Pumps, $200 delivered. Had to exchange the pump head due to mine being 1/2" and new one was 3/8".