pump priming issues, what am i doing wrong?

[wncbrewer]

I recently got a march 809, and have had some trouble getting it to prime up. It is probably a foot below my vessels and has a ball valve on the outflow side. I have tried turning it all directions, and putting it in different spots on my rig, sometimes it takes off like a rocket and others it struggles to start moving. I am scared of burning it up by running it dry. My hoses are sillicon and might be a little long, in other words, I left lots of slack so I could move the pump to best spot. Any help would be appreciated as usual. I am very new to the march pump, and haven't even brewed with it yet, so far have only done wet tests...thanks wnc

 

[rockytoptim]

I would recommend having the outlet pointing up. Secondly watch Bobby M's video on how to prime the pump. I had issues at first and after watching the video it was much easier. You can also add at T to the outlet side and but second valve on it so you can bleed of air once you have the hoses hooked up and before you turn the pump on.

Also check out this thread.https://www.homebrewtalk.com/f51/priming-march-pump-177690/

 

[Catt22]

Install a bleeder valve on the outlet side between the flow control valve and the pump outlet port. This is fool proof. Close the flow control valve and open the kettle valve. Next open the bleeder valve until you get some liquid flowing. Close the bleeder valve and open the flow control valve as desired. You do this with the pump on or off, but if the pump head is completely dry, it's best to get at least some juice into it before starting the motor. Regarding hoses, I would suggest using large diameter hose and keep the hoses as short as conveniently possible, especially on the suction side. I use 5/8" ID hose with nothing less than 1/2" ID anywhere including all fittings. Think inside diameter when working with these pumps and plumbing. It's the ID that counts and there is a huge difference between 1/4" ID and 1/2" ID, like 4 times the cross sectional area. My point is that small increases in the diameters make much bigger changes in flow rate. It can be deceptive as 3/8" OD tubing is only about 1/4" ID & 1/2" OD tubing only about 3/8" ID (those are approximate ID's, so YMMV). It can get even more confusing as there are different wall thicknesses available. Rigid pipe is usually given as the nominal ID rather than OD like tubing. Then I think there is refrigeration tubing that uses a different convention yet and their OD's can be slightly different than standard plumbing tubing. All of this is why there are always so many plumbing questions on the forum. Unless you are familiar with all of this gibberish it can be very confusing.

 

[wncbrewer]

Thanks, a bleeder valve is kind of what I was thinking, but I wanted to see what some of you march pump vets had to say, im also going to shorten my hoses up, they are cumbersome anyway

 

[coogee]

You should check all fittings before the pump for airleaks, retape and tighten them.
This could eliminate any need to bleed but possibly not I'll cede.

 

[benbradford]

i get air in my pumps when i switch the inlet tube from vessel to vessel, or the first use...i am careful to crimp the tube now when moving it, so that air is not pulled down line.

the solution for getting the air out, for me at least, is to lift the "out tube" high in the air, and the little water in the line pushes back to the pump (pump is off), the air burps back up the other end of the line (usually back into the vessel), and then fluid moves all the way back the line toward the pump, filling the pump, and down the "out tube". I drop the end of the "out tube" until I see the fluid, cover it with my thumb, and turn on the pump, starts right up!

kind of a lengthy explanation for burping the line

 

[wncbrewer]

Got it, that was my issue, once I figured out how to get the air out I had no problems. Brewed with it today and all went fine except for a leaky compression fitting on my counterflow, I think its defective, brand new and ive done nothing but fight with it, soldering everything before I brew again. Thanks for the help...wnc