Air Purge from the Heating system

thevdeub · #1 (**permalink**) 01-13-2011

I ve got really hard time to prime my pump and remove all air from my Webasto Heating system on my 43' Beneteau.
I checked the pump and it looks like it working. however, when back in place, filled the tank, etc... trying the best i could, i cannot get the outlet of the heater itself filled with water. worst, when i use the bleeder, i ve got the feeling it filling hose with air instead of leaking pressurized air. i can hear the pump turning water and air , but no pressure at all.
any advice hoe to force out the air ?

another dummy question: the coolant 50/50, is it only as an antifreeze or it helps for heat conduction and/or pump ?

the pump is a U4810 for a DW80 Webasto system.

tommays · #2 (**permalink**) 01-13-2011

I work on machines that are difficult to get the air purged out of the heating loops and we use and anti-freeze hand pump to force it through the heating loop

The pump just sits in a gallon of pre-mix and we hook it up to a valve we placed in the system for this purpose and pump while cracking the loop in various laces to let the air out

The coolant 50/50 also stops corrosion which would happen with straight water

thevdeub · #3 (**permalink**) 01-13-2011

sounds like a good idea. Thx.

deniseO30 · #4 (**permalink**) 01-13-2011

I'd like to help you but so much information is missing. Hydronic heating loops are the same regardless of application, boat, house, rv. If it's a loop. does it loop through blower units? if so they would have air bleeders on them. Or do you have what would be like baseboard heating? if so, the loop is pressurized from one end with water under pressure, (or in your case anti freeze and water) and all the air will eventually be forced to the other end if it is valved off behind a bleed or drain valve which is open until a steady stream comes out. The hand pump would work but you would be pumping allot if it's a long loop. If the "pump" is like most used in heating loops, It is a a circulator and only moves water. but cannot under pressure like a raw water impeller pump. Hope this helps! Hard to explain but it's quite easy in practice.