Ball valve for march pump, Necessary?

My setup recirculates the mash. As it is now the flow is only controlled by the valve on the mt, is this ok? I don't see the need to choke it twice, since you have to carefully control the flow out of the mt. Or is it better for the pump if you choke it(on the output side) more than the output flow of the mt?

Am I making sense, or do I need more sleep?

This is my impression (disclaimer: I don't own a pump):

March pump cannot be run dry, so restricting the in-flow (i.e. at the MT) is BAD....its possible that you can restrict too much and cause the pump to seize.

You want to restrict the pump on the out-flow, because that way its harder for the pump to be run dry.

The flow control valve should always be on the output side of the pump. Restricting the flow on the suction side would not harm the pump, but it could cause cavitation problems and possibly collapse the suction hose. The cavitation could also cause the pump to lose it's prime. You can still carefully control the flow out of the MT with the valve on the output side of the pump. That's exactly how I do it. Also, IMO, a gate valve works much better than a ball valve for this application as it allows more precise adjustment. You can expect that those who have big bucks invested in SS ball valves will most likely strongly disagree with this opinion.

You'll be OK if the connection between the MLT and pump is rigid but if it's soft tubing, it will likely get crushed due to the pressure drop when you really tighten down on the flow.

Catt22 said:

The flow control valve should always be on the output side of the pump. Restricting the flow on the suction side would not harm the pump, but it could cause cavitation problems and possibly collapse the suction hose.

Click to expand...

But you still can't run the mt wide open, or stuck sparge city. In hot water testing, I had no problem with collapsed hoses, that was with silicone, and some braided poly.

I ran a slow recirc for an hour with no problem, just wondered if it would harm the pump?

wildwest450 said:

But you still can't run the mt wide open, or stuck sparge city. In hot water testing, I had no problem with collapsed hoses, that was with silicone, and some braided poly.

I ran a slow recirc for an hour with no problem, just wondered if it would harm the pump?

Click to expand...

If you restrict the outflow of the pump you are still restricting the outflow of the MLT, just from ~2-3 feet further away.

camiller said:

If you restrict the outflow of the pump you are still restricting the outflow of the MLT, just from ~2-3 feet further away.

Click to expand...

Yes, but my question, and I know i'm doing a piss poor job explaining it it. Is it better to have a set flow from your mt, then choke that flow down a bit from the out side, thus insuring the pump cavity is always full. Is that necessary?

Like everything I do, am I over thinking this? I don't want to trash a pump if I can help it.

A valve on the output of the pump is the only way to control the flow downstream. There will be times when you want to turn the pump flow off momentarily or reduce the flow. And for optimum peformance, the pump head should always be full, or as nearly full as practicable. I pump out of a grant vessel, but I use the outlet valve a lot during recirculation.

wildwest450 said:

Yes, but my question, and I know i'm doing a piss poor job explaining it it. Is it better to have a set flow from your mt, then choke that flow down a bit from the out side, thus insuring the pump cavity is always full. Is that necessary?

Like everything I do, am I over thinking this? I don't want to trash a pump if I can help it.

Click to expand...

Personally, I like keep the BV on the MLT WFO and meter the flow after the pump via ball valve. My thinking, and I could be wrong, is I want the maximum amount of liquid going to supply the pump to guard against losing prime.

Hugh_Jass said:

Personally, I like keep the BV on the MLT WFO and meter the flow after the pump via ball valve. My thinking, and I could be wrong, is I want the maximum amount of liquid going to supply the pump to guard against losing prime.

Click to expand...

Good point. I guess if you choke it down on the outflow, you wouldn't get a stuck sparge with the mt valve wide open. I can't believe how stupid I am. I guess I shouldn't post with 3 hours sleep.

I agree with most everyone here. I think putting the valve on the output of the pump is the best option to guard against lost prime, cavitation, stress on the pump itself. I think you would be most happy in the long run by restricting your flow on the pump output rather than restricting from the MLT (or any other vessel for that matter).

You definitely want the valve on the output of the pump, not on the input side. The March pump uses the fluid being pumped as a kind of a 'bearing'. If it cavitates, or is run dry, you will ruin the pump head.

From the mash tuns point of view, it won't care where the valve is located, so there really is no good reason not have it on the output side of the pump and there are numerous reasons why not to control the flow at the MT outlet as many have already mentioned.

Nice Thread, I am in the process of buying my disconnects and this really helped!

If you don't already have the ball valve, I'd spend the extra cash on a gate valve. It's MUCH easier to adjust flow with a gate valve.

B

Advice taken...I still don't know why I have to match both bumps speeds...that's only for fly sparging right. If I'm b sparging can't I just open the gate valve from the out flow of the pump to the desired speed?

wildwest450 said:

My setup recirculates the mash. As it is now the flow is only controlled by the valve on the mt, is this ok? I don't see the need to choke it twice, since you have to carefully control the flow out of the mt. Or is it better for the pump if you choke it(on the output side) more than the output flow of the mt?

Am I making sense, or do I need more sleep?

Click to expand...

To expand, I used my pump for the first time this weekend, and I think I solved the pump priming dilemma. The answer.....you need three ball valves. Stay with me here.

I oriented my pump in the B3 style; pump at bottom of rig, input on the bottom, output on top. I attached a SS tee to the input. I attached 1/2xclose SS nipples to the two open ports on the tee, giving me all male connections from the pump for me to attach the ball valves to. The valve on the output controls flow, but on my system, usually stays completely open. The valves on the bottom of the pump, connected to the tee, are there for 1. priming, and 2. keeping the floor dry. On one of the input tee's BV, I attached my Poly QD. On the other BV, I connected a 1/2" MIP x hose barb, and I ran about 5 feet of vinyl hose from the barb.

The Poly QD is serving as your liquid input to the pump head. The valve this fitting connects to is always open, but can be closed once the pump is turned off to keep liquid from spilling out of the pump head, and all over the floor. The valve with the hose barb fitting was described by B3 as a bleeder valve, but I am going to call it the "priming valve". When I am ready to transfer liquids, I open all the valves in the line I want to move liquids along, and the only closed valve is the "priming valve". After a few seconds, the liquid will reach equilibrium , but undoubtably, there is air in the lines. I lay the 5' if vinyl hose on the ground (below the height of the pump) open the priming valve, and allow the 5' to fill with liquid. Before it can flow out the end of the hose, (keeping the priming valve open, mind you) I elevate the vinyl hose above the height of the vessel that is feeding the pump, through gravity, forcing the liquid through the lines and flushing out all of the air. I close the "priming valve", and turn on the pump. I swear, it works like a charm.

I was able to move boiling liquids, recirc a mash, and run a Jamil-o-chiller with no problems.

Good Luck,
Joe