Do March Pumps "suck"?

[captaincleanoff]

about to get a march pump, and just thinking about a few things before I do.

I can remember that march pumps dont really suck through the inlet, they only have power on the outlet side. Is this true?

I'm just worried about it 'sucking' too hard and pulling grain from my MT. Or would it be good idea to use some flow restictor?

 

[barls]

just fit a ball valve to the out let side and you can control output through that, slow the flow down and it will be fine,

 

[A3k]

They require priming, so wont pump unless theres liquid in the pump.

As for the suction, id be putting a valve on in-line with the pump, and adjust this the provide flow control. Otherwise i suspect the flow will probably be too high and compact the grain bed (depending on your system and how long youre pumping for).

Ive got a stainless false bottom in a keg. I decided to recirc for the majority of a mash once. Thinking my falsie was invincible, i didnt restrict the flow and ended up with a stuck sparge.

Hope this answers your question.

Al

 

[unrealeous]

[Way too slow but I'd written it anyway]

They won't self prime - but once all lines are full of water - as they push the fluid out, the inlet side will 'suck' as you like to call it.

As for flow restriction, you can adjust your valve position of your MLT to control the flow. I've never had a problem. And if you are worried about a few grains in your line - the march pump is magnetically coupled so it won't do it any damage.

 

[QldKev]

As already mentioned you will need to have some s/s braid or some kind of false bottom in the mash tun.

And when resticting the pumps flow, it's recommended to restrict the outlet side, and not the inlet.

QldKev

 

[newguy]

My soon to be obsolete HERMS uses a march pump to constantly recirculate. The liquid lines from the mash tun to the pump and pump to the heat exchanger are 1/2" ID, and my heat exchanger coil is 3/8" ID. I have not had a stuck sparge or runoff with this system, other than the time I experimented with corn starch (don't ask). However, I do not run the pump during the runoff/sparge - I let that happen via gravity alone.

My false bottom is similar to this one, in that it sucks up from under the mesh, then out the side of my mash tun.

In my experience, all you need is a bit of a flow restriction and you'll be fine. I don't know what would happen if all of my lines were 1/2" ID.

 

[Thirsty Boy]

Valve on the "out" side of your pump - if the inlet restriction is too high, the pump can cavitate and that will damage it. Restriction on the outlet side wont cause cavitation or damage. You can shut the valve completely and the pump will happily spin away with no flow at all.

 

[fraser_john]

Per others, flow control on outlet.

They can suck enough to totally compact a grain bed to the point of no flow, can result in RIMS boiling or HERMS HEX overheating if flow does not exist, once again, by experience on both counts!

Brewer beware, I do need to get around to putting temp control in my HERMS Hex itself to stop glycol boiling when I forget to shut power to SSRs off! I have the additional basic PID, just no time to do it.

 

[captaincleanoff]

so the ballvalve on my boiler is all I really need to control the outlet?

 

[Crusty]

so the ballvalve on my boiler is all I really need to control the outlet?

No.
Leave that one where it is on the boiler & install another one on the pump outlet.