Braumeister pump control

[ozroger]

Before today's brew session, after filling the BM (50 litre) and purging air from the pumps (the BM 50 has two) I noticed the output from one was well below the other. No strange noises, just not much flow from the top of the conduit I was temporarily plugging into the outputs, with the top of the conduit above the water level.

So I emptied the BM, inverted it, inspected the impellers and the intake & outlet pipes, and all good.

The rotary switches on both pumps were still in the original positions, as evidenced by the red "sealing wax". So - what's going on?

Back on it's feet, I poured about ten litres water back in, and ran the pumps. This time, I fiddled with the rotary knob of the problem pump - back and fro - and got the pump output back up to match the good one. Then continued with the brew.

During cleanup, I saw that the knob was now very close to it's original "sealed" position. It's the RHS one in the photo:

BM pumps.jpg (77.47 KiB) Viewed 2876 times

Does anyone know the workings of those knobs and what the graduations signify?

[IPA]

Not sure that I can help you with this problem. On the very first BM I owned,a 25, I had endless problems with the pump. It appeared that the impeller had become partially de-magnetised. Speidel sent me a new impeller and when that went the same way they sent me a new pump. Not long after I bought a 50 and after a couple of years both pumps lost power. It was long out of guarantee so I bought two new pumps and by this time they had changed the make of pump and now, ten years later, both are still going strong. So to sum up Speidel have used at least three different models of pump including the variable speed model that you have.The first make was Vortex the second was Lowara and the variable speed model that you have, which I think, is also Lowara.
Getting back to your problem I will hazard a guess and say that the impeller has a magnetic problem and that by increasing the speed slightly you have upped the flow rate to equal the other pump. You say that you checked the impeller. Did you also check that the holes in it are all clear of any débris ?

[ozroger]

Yes, I always put the impeller up to my lips and blow hard, then visually check that the holes are clear. Today, I even swapped the impellers to see if the problem moved, but it didn't.

I wonder whether the control knob simply operates a wire-wound potentiometer, and that by tweaking the knob back and fro, it re-made proper contact? Could it be that simple...?

[MashBag]

Could defo be that simple. Just a tired contact, that you remade.

When I clean my pump I stick the impeller to the steel wall and leave everthing to dry. Would be a simple test to check for any magnetic fade.. Just stick them to something.

I have lowara pump (brass collar). Not problems here. Red spot seals it on max.

[MashBag]

If the knob, comes off a squirt of 'servisol' would help.

[ozroger]

OK - it turns out the pump is a type commonly used in re-circulating How Water Systems. On my BM, they're the Laing E1vario. So variable speed control, so I'm sure that no harm will be done to the pump by moving the speed control from one extreme to the other. Just which extreme was Speidel "factory set" I don't know, however I'll try it out WITH WATER IN THE BM! It's detrimental to the ceramic pivot the impeller sits on, if the pump is run dry, as the fluid is the lubricant for that.

Another variant of the E1 is thermostatically controlled for when used in a recirc HW system.

I did remove the back cover of the pump body (one screw to undo) and the shaft from the control knob disappears somewhere in the guts of the thing, so a spray with whatever - Servisol, WD40, brake cleaner, etc - probably wouldn't do anything beneficial. But good thought!

[richard080561]

Did the BM come with the pump spped controls sealed? The original pump on my BM20 didn't have speed control but when it packed up the replacement was a newer model with the speed control. The control wasn't sealed and I remember finding some recommended settings on the BM website.

[ozroger]

Yes - when I bought my BM 50 second-hand a few years ago, the speed control knobs were sealed into position with red sealing wax. I assumed this indicated they were not to be fiddled with.

But now that I have (fiddled) I'll experiment further. I imagine there is an optimum setting to ensure a good circulation through the malt pipe, without being excessive. I'll do some research too, to see if I can find the Speidel recommendation for these impellers. I believe there are newer design impellers with different speed recommendations, just to make things interesting.

[IPA]

Hi Roger
Intrigued by your pump test I tried the same on my BM 50 and sure enough one pump was more powerful than the other.
Looking down from the top with the tap at the front which one,right or left was the most powerful ?

[ozroger]

G'day Ian - the RHS was the most powerful. This is also the side I modified with the "lower drain mod", however during that mod the pump setting was not touched.

For comparison, I'll add some water to the BM this morning, turn on the pumps, and in turn take photos of the fountain of water out of the top of the conduit. Due to the lack of a 100% seal between the conduit and the base of the BM, It's not a really scientific test, as the conduit is simply pressed into the outlet depression a little, but it should give some idea of the flow rate - if that makes sense...

[ozroger]

Update on pump head:

This is the flow from the top of the 19mm (3/4") conduit. Wall thickness is 2mm, so ID is 15mm.

BM pump head.jpg (52.11 KiB) Viewed 2752 times

Both pump controls are in the max position, and the output from both is pretty much the same.

So for any BM50 owners, it's probably worth a check on your pump outputs, as IPA said, to ensure a good match.

[IPA]

Hi Roger
I put a piece of pipe, of the same length, in each outlet and the flow rate was higher in the left one !
There is no speed control on my pumps so there is not much I can do.