Discuss: Pump Priming

[Bobby_M]

Nope... a one mile diameter inlet has a lot more weight. The pump doesn't provide suction at all. You need the weight of the liquid in the inlet tubing to push the air out of the pump head.

To the point of the siphon tube filling with air/steam and then flushing into the pump's inlet line.... I just ordered a brass schrader valve stem from Mcmaster and I'm going to drill into the elbow of my brass QD and solder that sucker in. A little tap on the valve should let the air escape from the line.

 

[Boerderij_Kabouter]

To the point of the siphon tube filling with air/steam and then flushing into the pump's inlet line.... I just ordered a brass schrader valve stem from Mcmaster and I'm going to drill into the elbow of my brass QD and solder that sucker in. A little tap on the valve should let the air escape from the line.

Brilliant! And to go one up from there, why not use a Presto valve, cut off the base, tap and thread a hole into the output somewhere, and thread the presto into the tapped hole. Also, presto valves can be locked down.

Awesome idea!!:rockin:

 

[FSR402]

It said a larger hose in the suction/inlet side. Take an extreme example; what would be easier to prime: a 1/4" ID tube or a 1 mile ID tube? See how hard it would be to get a good prime on that 1 mile ID tube? But just a little suction on the 1/4" tube would prime it easily.

IMO, it's not really about getting the air out per se...but more about getting pure liquid to the suction side. Once you get pure liquid at the suction side you're golden...the pump will take care of getting the air out (as long as you give it a path).

The only way you would be sucking it would be if the pump was higher then the kettle.
I understand what you're saying but what they are saying is that a higher volume of fluid going into the pump works best.
So with a larger hose in the inlet there will be water/wort "waiting" to be pumped thru.

 

[SpanishCastleAle]

I see what you're saying FSR402. But if the kettle is above the pump then the pump should already be primed. Since people were having problems priming I assumed that wasn't the case.

Just because it's primed doesn't mean it will move liquid though. There could be too much head pressure or the pump could be cavitating, etc...but that's different than 'not primed' imo.

The pump doesn't provide suction at all.

Of course it does. There is suction on one side and pressure on the other. Since it's centrifugal it's not a lot (esp when not primed)...but it wouldn't work if it didn't have a differential pressure across the inlet/outlet. How does the liquid 'know' to move? The pressure gradient.

 

[conpewter]

All my pots are above the pump but I still have to get it to prime, then again mine is not a march 809, it is supposed to be used in conjunction with water pressure (circulator pump)

 

[flyangler18]

I see what you're saying FSR402. But if the kettle is above the pump then the pump should already be primed. Since people were having problems priming I assumed that wasn't the case.

March pumps aren't self-priming.

 

[cdburg]

I think everyone has a plan figured out, but just in case someone else is looking for another idea, I recently added this to my pumps. Opening the side valve until liquid flows through then closing it and opening the top valve it gets everything flowing almost every time.

 

[FSR402]

I think everyone has a plan figured out, but just in case someone else is looking for another idea, I recently added this to my pumps. Opening the side valve until liquid flows through then closing it and opening the top valve it gets everything flowing almost every time.

why wouldn't opening the the top valve do the same thing?

 

[SpanishCastleAle]

March pumps aren't self-priming.

I know...I've been using them at work for years. Often mine won't pump liquid either...but it's not because they aren't primed. 'Not primed' isn't the same thing as 'too much head pressure' or 'impeller cavitating'...both of which will prevent the pump from moving liquid.

 

[missing link]

I think a lot of the trouble with getting the pumps to move liquid is due to the fact the inlet and outlet are both above the pump. As soon as you get the outlet below the inlet you get instant flow. That is why the valve in the picture above is so effective. It lowers your outlet by a few feet creating less resistance to pumping.

Linc

 

[cdburg]

why wouldn't opening the the top valve do the same thing?

When the lines are hooked up to the pump, in my experience, opening the top valve does not do the same thing. I can't explain why, scientifically. Before I switched to this set up, getting the pump to push liquid through my heat exchanger was really tough. Between the air in the lines, exchanger and pump head, it was very tough to not end up with a captivated pump. The new set up makes it simple to get everything flowing.

Just opening the top valve toward the tubing does not allow it to pump. Having the second valve open to let the air out before it hits the tubing makes a difference. I can then switch to the top valve to send the pumped liquid through the tubing.

I got the idea here:
Morebeer's Brew Chat • View topic - March pump "head' question

The set up is described in some detail there. Hopefully it helps someone.

 

[Bobby_M]

Here's what I came up with to vent the air bubble out of the inlet tubing. This is the QD that goes on the vessel I'm pumping from.

For now I plan to leave the valve assembly out of the stem and just loosen the cap to vent. I'll write up more after I test it out.

 

[FSR402]

Here's what I came up with to vent the air bubble out of the inlet tubing. This is the QD that goes on the vessel I'm pumping from.

For now I plan to leave the valve assembly out of the stem and just loosen the cap to vent. I'll write up more after I test it out.

are the seals and cap rated for the temps they will be put thru?

 

[slimer]

Looks like a schrader valve, so the cap is there just to provide some protection. It works like this:

 

[Bobby_M]

I know how a schrader valve works. I unscrewed the valve assembly and decided to leave it out for now because that air pocket isn't going to be under much pressure. I'm pretty sure the cap can handle the temps but if not, I have a metal one. During a brew session, I'll go ahead thread in the valve to see if it works but poking something in to push on the pin would get really annoying.

I actually meant to have the tube sticking up but totally beefed it when I drilled the hole. Having the elbow part disassembled from the QD screwed up my perspective and I was in a big rush.

 

[slimer]

I know how a schrader valve works. I unscrewed the valve assembly and decided to leave it out for now because that air pocket isn't going to be under much pressure. I'm pretty sure the cap can handle the temps but if not, I have a metal one. During a brew session, I'll go ahead thread in the valve to see if it works but poking something in to push on the pin would get really annoying.

I actually meant to have the tube sticking up but totally beefed it when I drilled the hole. Having the elbow part disassembled from the QD screwed up my perspective and I was in a big rush.

I was replying to FSR402.

It looked like you put a schrader valve on your QD. Sorry for the misunderstanding.

But if you're thinking about adding one, the ones on bikes are very easily pushed in. You can do it by hand and there's a second set of threads to tighten it so there's no leaks.

 

[Bobby_M]

No problem. I picked up this schader on mcmaster. It actually had 1/8" NPT male threads on it but I didn't have a tap. An NPT tap and die set is really something I'd love to get my hands on but they're really pricey.

 

[fifelee]

Liked Bobby's idea so much thought I would give it a try.

Have you tested it yet bobby?

 

[Bobby_M]

Niiiiice. No, no brewing in my near future. Kitchen renovations ...

 

[nathan]

if you hook up too much stuff right away, the pump will have a hell of a time priming, so I start with just one section of hose at the pump outflow (where I have a valve as well). Turn on pump, when I prime enough to fill the in and out hoses, I turn off the valve and go put the hose on where I want it (you can kink the silicon to drip less while moving).

You may find that if you have dip tubes in your vessels that air gets trapped in them (all three of mine are like this). I find that the very first time I need to use those valves, those tubes are full of air and stuff doesn't want to prime and start. So I hook up hose from ball valve to pump, and hose from pump to nothing, and I open the ball valve and just give a good suck on it, which will pull the air into the first tube. then angle the tubing up so it's trapped in a high point, and work it down to the pump. Once it rises up through the pump you are usually golden.

One hint for avoiding this issue is to fill your vessles through the ball valves, at least for a second or two, so the tube is full of fluid, not air.

 

[Evan!]

Well, I'm glad this thread has spawned some good ideas. Personally, I think I've been able to get my process to where it doesn't need an air release valve. Just open the kettle valve, wait a few seconds, then turn on the pump.

 

[Bobby_M]

The issue that the release valve is meant to fix is that even after you let the liquid settle into pump head, there's some air in the input line between the pump and "from" vessel. The pump will start but then get airlocked. To Nathan's point, there are tricks to get rid of most of the air. One trick I use is to open the "from" vessel's valve with nothing attached and catch the dribble in a cup. This at least fills the siphon tube and ball valve with liquid.

 

[Evan!]

The issue that the release valve is meant to fix is that even after you let the liquid settle into pump head, there's some air in the input line between the pump and "from" vessel. The pump will start but then get airlocked. To Nathan's point, there are tricks to get rid of most of the air. One trick I use is to open the "from" vessel's valve with nothing attached and catch the dribble in a cup. This at least fills the siphon tube and ball valve with liquid.

Oh, I know, I realize that---what I'm saying is that, with my setup, as long as I open the valve first and let the head fill with water, I don't get "airlocked". Everything works fine.

 

[conpewter]

The airlock in the siphon tube is why I ended up switching to a bottom drain tube on the boil kettle. The HLT still has a siphon tube so I let it dribble a little if I don't remember to fill through the tube.

 

[nathan]

I ran my wort from the mash tun to the kettle ball-valve to ball-valve with the pump this time, and my first run out of the kettle had no air stuck in it (I pinched off the tubing and switched it on the pump to pump out from kettle).

Anyway, I did two batches in a row, had no issues beyond a few seconds of cavitation, so I think you just get so used to how to do it you can do it without even realizing it. It wasn't until I saw this thread again that I remembered.

 

[Denny's Evil Concoctions]

I have a T on the outlet with two ball valves and 2 QD's. I vent with whichever isn't hooked up to the hose and it also lets me take samples during the transfer to the BK etc.

With a ball valve I don't burn my fingers.

 

[fifelee]

I tested mine last weekend. Worked like a charm. No more priming problems for me. Yippy.

 

[doggage]

Looks like a schrader valve, so the cap is there just to provide some protection. It works like this:

I may not know the solution to the priming problem after having read this post, but I certainly do know the internal workings of the Schrader valve. And for that, slimer, I am forever indebted to you. The things one just takes for granted...

 

[lehr]

Mine.

 

[beerthirty]

Never saw this thread before lehr brought it to the top. Here is how I handle it.

these are vacuum breakers, mounted on each side of the pump. They contain floats that rise when liquid enters and seals the valve. With air present they fall and allow liquid head pressure to purge the air and then reseal. The NPT port has a bubble breaker to prevent surface tension of the liquid from blocking the port. I have one on the inlet of each pump to allow priming when the pump cavity is full but the line is empty, and one on the outlet of each pump so when the pump is turned off air that is trapped in the outlet lines or valves cant flow back to the pump and vapor lock the pump. I have yet to brew with it but have done 3 brew temp wet runs with 100% success. The red button is for the automatic purging and the black button allows you to manually purge.
link to the duovent. Auto Dual Air Vent,Hot And Cold,1/4 In - Vent Valves - Valves - Plumbing : Grainger Industrial Supply

 

[SpanishCastleAle]

That looks sweet beerthirty. Looks like a big-block.

Those aren't technically vacuum breakers. I mentioned these degassing valves in post 22 of this thread. A vacuum breaker works such that if you put one on the suction side of the pump it would open and your pump would just keep pulling air through the vacuum breaker. A vacuum breaker prevents you from pulling vacuum...but seals with positive pressure.

EDIT: Vacuum breakers prevent stuff like this from happening:

 

[slimer]

That looks sweet beerthirty. Looks like a big-block.

Those aren't technically vacuum breakers. I mentioned these degassing valves in post 22 of this thread. A vacuum breaker works such that if you put one on the suction side of the pump it would open and your pump would just keep pulling air through the vacuum breaker. A vacuum breaker prevents you from pulling vacuum...but seals with positive pressure.

EDIT: Vacuum breakers prevent stuff like this from happening:YouTube - Tank car implosion d'un wagon citerne

I work in the rail industry and have seen that video so many times! It never loses it's gusto.

 

[beerthirty]

I had always called them automatic air vents but others had called them vacuum breakers. I wasn't aware of the difference. Thanks

 

[FailureDrill]

Based on this thread, this is what I came up with. Worked awesome, thanks for the help.

 

[Grimtas]

Out of curosity why is everyone still using the left/right in/out puts when March makes a center inlet side outlet? I still need to buy the pumps for my rig and was planning on the center inlet route mounting the pumps verticle for easier plumbing. Thoughts...

 

[IrregularPulse]

A lot of people I imagine (myself included) just see so many people on here using this pump in this configuration and when they think Brew pump that's what they think and order. I got a great deal on my pump from another member on here however switching to the center input one.

 

[rcrabb22]

Out of curosity why is everyone still using the left/right in/out puts when March makes a center inlet side outlet? I still need to buy the pumps for my rig and was planning on the center inlet route mounting the pumps verticle for easier plumbing. Thoughts...

One reason might be the different inlet size from the opposed inlet model. The 809 PL-HS-C model I have seen available has an inlet combination of 3/8" FPT and 3/4" MPT with a 1/2" MPT outlet. The opposed model used 1/2" MPT for both inlet and outlet.

 

[Grimtas]

One reason might be the different inlet size from the opposed inlet model. The 809 PL-HS-C model I have seen available has an inlet combination of 3/8" FPT and 3/4" MPT with a 1/2" MPT outlet. The opposed model used 1/2" MPT for both inlet and outlet.

Ahh I missed the 3/8 3/4 Inlet on the C. But now that derives another question wouldn't a 3/4" inlet be easier to prime. I know the rig would require different plumbing on the outputs from the kettles but with a gravity feed on 3/4... bah nvm my outputs from the kettles are only 1/2" so that won't work. Back to my coffee.

Thanks for the inputs.

 

[hedonist91]

Mine.

Hey I am doing research on my pump setup, because I ruined a brewday with a march 809. So, I don't have a bleeder valve. I know now that it would be beneficial.
In your set up here, wouldn't you want the input to be facing up, allowing gravity to push into the pump too? I was under the impression, too, that you'd want to prime by turning the pump off and allowing gravity to run liquid through it first, then fiddle with turning it on and off and using the bleeder valve.
The orientation of the head on my pump is the input is straigt into the pump the long way, and then the output is out the side.
Sorry, no pics-I sent my pump with one of my friends to some mechanical genius guy who's going to look at it. Just trying to figure out how I should mount the pump when/if I get it back (maybe I ruined it?)
Thanks guys,.

 

[AlchemyBrewing]

I would love to hear what Bobby finally settled on and how it is working. I blew up a brew day yesterday pretty bad and the March Pump was definitely one of the many killers I encountered.