Simple Hand Primer For Magnetic Pump

[Brew Matt]

I am sure this has been covered here somewhere, but have not found it.

Looking for a simple hand primer that I can use to get a magnetic pump working (the pump is not self priming, and is above the source water that it is drawing from).

I have standard garden hose connected to the pump, and this connects to an immersion chiller.

So looking for something that will attach to a 3/4 BSP hose, that can be squeezed to get the water flowing, then the pump can take care of things after the flow has started.

 

[sp0rk]

Is it pumping wort or water?
If just water, I think a Y valve in line acting as a venturi connected to the mains, to suck the water through then flick the pump on after a few seconds
Then shut the mains off once everything is moving

 

[MHB]

Move the pump!
If you have a suction head (I know, but that's what its called) and you try to pump boiling or near boiling liquids there is a very good chance of getting cavitation where the liquor boils in the impeller and pump stops pumping, even if it doesn't stop pumping it will rapidly ware the pump impeller.

Locate the pump at the lowest point in the circuit.
Mark

 

[TheWiggman]

Mark's on the money, there's nothing simpler you can do than move the pump. Seeing as you're using garden hose and mention a chiller, I assume you're trying to suck water out of a pond or bucket. There are three 'simple' options.

1. Fit a jiggler syphon to the suction side of the pump and jiggle until it's filled
2. Header tank. There are a few arrangements from simple to complex but the more complex the better the chances of it working. Have a small tank of water teed into the discharge side of the pump and drain water back through the pump into the tank/pond. Once full, turn on the pump and close the valve to the tank. You'll run into airlock problems doing this, to get around this you'll need a valve below the tank/pond level or a foot valve on the suction.
3. Plumb a priming line using tap water to achieve the same as above, or as sp0rk said.

In industry the most common method is to prime the suction side of the pump using an external water source. In this case the pipework is often fitted with an air bleed valve.
Another simple alternative it to just suck from the discharge side of the pump using your gob and turn pump on when primed.

The suction head mark is referring to is known as the parameter net positive suction head, or NPSH in the pump world. More critical with powerful pumps and hot fluids. Shouldn't be a problem in your case but if it's a problem you need to consider, you're probably being too complex. In general in can't exceed 9m for water at sea level and if your pump has a max head less than this (3.4m for Kaixin), you need it to be a lot less than that if you want any flow.

 

[Brew Matt]

Is it pumping wort or water?
If just water, I think a Y valve in line acting as a venturi connected to the mains, to suck the water through then flick the pump on after a few seconds
Then shut the mains off once everything is moving

It is pumping cold water only. I am currently holding a mains water hose to the input for a few seconds to get things going, then all is well.

Thought there may be an easier way, and would be handy to have a method of priming should mains water not be available.

Move the pump!
If you have a suction head (I know, but that's what its called) and you try to pump boiling or near boiling liquids there is a very good chance of getting cavitation where the liquor boils in the impeller and pump stops pumping, even if it doesn't stop pumping it will rapidly ware the pump impeller.

Locate the pump at the lowest point in the circuit.
Mark

Not possible to relocate the pump. It is not a rig, just a simple and temporary setup to pump cold water up to and through immersion chiller. Saves water as the used water simply goes back to the source (though hotter).

 

[Brew Matt]

All plumbing advice appreciated, but i was thinking something simple and cheap like the attached primer bulb (photo), but with the correct size 3/4 bsp end. This would be held under the water line at input end of the pump. A few squeezes, and hopefully that would get the air out of the line, and the pump would then manage after this.

 

[sp0rk]

All plumbing advice appreciated, but i was thinking something simple and cheap like the attached primer bulb (photo), but with the correct size 3/4 bsp end. This would be held under the water line at input end of the pump. A few squeezes, and hopefully that would get the air out of the line, and the pump would then manage after this.

Could you possibly plumb this inline using a tee fitting, reduced down to the size you need on the primer bulb line
Then prime to fill your lines, before turning the pump on
Having it purely inline would surely reduce flow far too much
Plus I've never seen one over 10mm in my years sailing and rescue boating

 

[TheWiggman]

If you use that (and I think you should, that's easy as buggery) then make sure you fit a foot valve to the end where the water is being sucked from. This will make sure the primed water doesn't just flow back to the water source. You'd need -

• 20mm foot valve
• 20mm barbed fitting
• Barbed male tee - if not readily available, you'll need a tee and 3 x connectors as above

Connect tee to the suction side of the pump. Squeeze away until the pump is wet, then turn on. Just make sure the tail of the primer bulb remains in water else the pump will try to suck air through it.

 

[sp0rk]

Aren't primer bulbs usually a 1 way valve by design?

 

[TheWiggman]

They are. If the pump was on though and the primer valve wasn't in water, it could suck air through it in the direction of flow. That's assuming it was teed into the pump's suction side.

 

[Camo6]

Here you go. Use a peristaltic pump to prime your magnetic pump. Kinda like buying a Mercedes to jump start your Falcon.