DC Pump for Water Circulator

The windshield washer pump will probably burn out, they are rated for very intermittent use.

A small commercial peristaltic pump will do the job (like a big version of your windshield washer pump)

You don't say what country you are in!

In UK the company I work for could help chemicalcontrols.co.uk

Do a search for 'peristaltic pump' you may find a single pump unit designed for dosing detergent into small commercial dishwashers/glass washers will do the job nicelyat a reasonable price.

Del

another option is to use a pump from a tabletop water feature.....

Common bilge pumps are 12V DC and very reliable in continuous or semi continuous use.

Check out Rule pumps (http://www.rule-industries.com/products/pumps/index.htm). The bilge pumps might be higher flow rate than you need (they start at about 360 gph), but they have some smaller types. They are pretty cheap and you can find them at a local marine shop or on ebay pretty easily.

Those pumps are made to work under significant head, so if you want to lower the flow rate, you can partially cover the intake without worrying about burning out the motors.

They also work well with simple pwm control if you end up wanting to vary the flow rate.

Small fish pond or fish tank pumps might work well also.

we used a brass oil pump with a step down motor it has about 1 gallion per hour of transfer and can run forever no problems.

princess auto was where i got the pump and the motor

Richard

Check out part suppliers for motorhomes and recreational vehicles.They all use 12 volt pumps for fresh water systems. Most of these pumps are for cold water supply, finding a pump for hot water (50 deg. C) may be a challenge!!!

Best of Luck, Gary

I'm tempted to say use a 12V to mains inverter and a central heating pump.

Both are common and therefore cheap items.

When asking for pump, It would make a lot of sense to specify flow rate.

A bilge pump is a good idea as long as your temperature is not over 35°C, What you need is a hot water circulation pump same as used on diesel water heaters or alike. Try to google Kabula Heaters, 12/24VDC BOLIN pump, if the flow rate you need doesn't exceed 10GPM or so.

Hope it helps,

Wangito