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Central Heating Pump

Steve Goddard

By Steve Goddard
in Boat Building & Maintenance

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Steve Goddard Collaborator

Steve Goddard

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I'm looking for a good central heating pump. I really want one which is very low consumption (<10w on lowest setting) and will handle a 50% Glycol mixture. Pumps which are rated for high Glycol tend to be solar and are 60w+ or low consuption pumps which are only rated for 20% glycol. I suspect that the main factor is the greater viscosity at the higher glycol levels needing more grunt.

 

Any suggestions

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Neil2 Veteran

Neil2

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Kuranda seem to recommend Bolin, I have one and I'm constantly amazed that something so small and quiet can actually do the job. The current draw on these though is tiny, I think as little as 2 watt so I wonder if they could move high viscosity liquid.

 

Having said that when I had a radiator leak not long ago the fluid that seeped out seemd to have a pretty high concentration of anti freeze.

Edited by Neil2
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Chalky Experienced

Chalky

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I use a Bosch engine auxiliary coolant pump. Designed to run with high glycol levels. The impeller is magnetically separated from the motor so it doesn't leak and lasts ages. It draws just under 2A so its higher than you want but you could PWM it to slow it down and this would drop the current down. It's a bit too powerful for my system - you can still hear the water moving found the system about 15 second after you turn it off!

Edited by Chalky
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casper ghost Influencer

casper ghost

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I use a Bosch engine auxiliary coolant pump.

I use one of these for my engine water pump, only cost me £1 from a scrap car, they are rated to 20,000 hours so even one from a scrap car will have plenty of life left in it. Mine is working fine, 12 volt of course though..

Casp'

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Steve Goddard Collaborator

Steve Goddard

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Why a 240V pump on a boat? :huh:

 

You could run a 12V pump off a 12V power supply, if you really want. :)

 

cheers,

Pete.

 

 

The Vintage range which does cooking and heating is 240v so it seems to make sense to have the whole heating system running on 240v. It does mean that some things are easier/cheaper as I can use domestic equipment rather than "marine" stuff with the associated premium. I've got to ensure an adequate supply of 240v to run the range so the other stuff is not a big additional drain. My ULV is 24v

 

 

Regards

 

 

Steve

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Steve Goddard Collaborator

Steve Goddard

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Jabsco do an 'Eco-circ' pump that has five settings, and looking at the pump curves it seems to go down to bolin-type current draws as well as going up to higher pump rates.

 

 

I think this is based on the Lowara pumps(owned by Xylem who were part of ITT who own Jabsco I think :rolleyes: ). They all seem to be the same company at the end of the day. The only issue I have with some of this is I spoke to a very helpful technical guy at Xylem and while he said that any of their pumps which are rated for Glycol are happy up to 20% they simply would not guarantee them to work as well / properly at concentrations above that. Given that the viscosity of water at 25c is 1 mPas and Glycol at the same temp is 16.1 I reckon a 50/50 mix would give a viscosity of around 8mPas. I don't know what that means in real terms but my simple outlook says it's a lot more viscous than water and I think that this is the real issue. Maybe I shouldn't worry and just bung a pump in and see what happens ;)

 

 

 

I can't find any good technical info on this pump on the jabsco site but I'll dig around a bit more.

Bit worried about the statement on the Bolin page "Please use Propylene glycol in your systems. The glycol also has a smothering effect on the Bolin Pump" Given that most of us are using Ethylene Glycol I wonder what that means dry.gif

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smileypete Veteran II

smileypete

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OK, maybe have a look at a Grundfos Alpha2, efficient, plenty of grunt, numerous modes to play with. But not cheap and might not like MSW power.

 

But if a Bosch circulator (or two?) can be sourced quite cheaply that could be worth a shot too.

 

Proplylene glycol is considerably less toxic than ethylene glycol.

 

cheers,

Pete.

Edited by smileypete
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