Issue with my new AG setup

[lowriderdog37]

I finally got off my butt and got back into brewing. As a reward, I finally made my recirculating mash tun.

This is not my first attempt at all grain brewing but is a huge upgrade from previous version. I have done 3 batches with this setup now, they all taste great but I am having flow problems.

I am using the following false bottom:
http://www.northernbrewer.com/brewing/brewing-equipment/all-grain-equipment/false-bottoms/12-s-s-false-bottom.html

The first batch I had used a vinyl tube to connect the false bottom to the valve, but I thought it collapsed as I kept loosing flow. I then replaced it with the PVC reenforced tubing and the same happened. The other day I plumbed it with CPVC and made sure there was a spacer holding the false bottom off the floor of the cooler.

My issue is when I turn the pump on to recirculate or pump the wart into the pot, I get about a minute of great flow, then it backs off to a trickle. The only way I can get it going again is to stir the bottom and loose my grain bed "filter". Even when I am done with the grain, I hose a bunch of water in the mash to cool it down and it still just trickles for hours unless I disturb the bed. Am I missing something here?

 

[chapa]

Not sure, but are you opening the valve 100%? You will want the valve at the mash tun to be open all the way, but you will want to restrict flow AFTER the pump.

Its also important that the pump is primed properly also. Bobby M had a good video on that. Basically open the valve, let your hose that's attached to the mlt fill up as much as possible, turn off the valve, connect hose to your pump, then open the valve again on the mlt AND open the valve on the pump, and LET THE PUMP FILL UP, THEN turn it on.

You might already have these points covered, but figured they were worth mentioning. Good luck!

 

[lowriderdog37]

I appreciate it, I am usually the guy that will forget to plug the computer in and think it is toast. I do prime the pump and leave the valves all the way open during operation.

Like I said, I get a great flow for a minute or two then it trickles down to nothing.

 

[S0meB0dy]

I do prime the pump and leave the valves all the way open during operation.

If you are leaving the valve on the outlet of the pump all the way open that is likely your problem. Start out with it just partially open and open it up slowly until you get a decent flow rate. With the valve all the way open you may be pumping the wort too fast and compacting your grain bed which results in your trickle after a minute.

 

[lowriderdog37]

hmm, kinda makes sense. I'll give it a try. Thanks!

Anything else I should consider?

 

[chapa]

Yup thats what I was getting at, aside from priming the pump. Make sure you restrict the flow after the pump, but definitely RESTRICT the flow. That should be the issue.

 

[nate456789]

I ditched my round cooler and false bottom setup like yours after 2 batches.
Around 150 deg the bottom would swell up and slow the flow and even completely blocked it with the second batch. Maybe stirring it is relieving some of the down pressure from the grains on the false bottom.