Review of a Kaixin MP-20R
I purchased a Kaixin MP-20R from the
link supplied by Wolfy.
Background
I've been running a march 809 on my main 3V for a while and have been happy with it. When it came time to build a smaller testing system to allow me to run single sized batches for test recipes and beers like weizens and a lambic where I don't want multiple cubes full, I wanted something to run it without the need to remove the march from the main system and risk damaging it. After trying a brown pump, which I proceeded to break during mounting (my fault as I could see how thin the housing was), then gluing it back together to find it didn't flow to my requirements for THIS system, I proceeded to order a kaixin pump.
Delivery Time
Ordered Sun 7th arrived Tue 16th.
Un-packaging
Looks like as per Woly's pic, but mine is slightly larger and is white. Same box arrangement.
Wiring
This morning I got up and put a plug on it. The cable is thin, which is acceptable as the motor draws bugger all current. The plug I purchased is suitable all the way down to 2 core 1mm2 (the motors cable is 3core) The cable lock will not screw down far enough onto it to grip, so if you wire one up you need to think about this.
Sizing
I went the MP-20R for the higher flow for my 'testing brewery' as I wanted to redirect a lot of the flow back at the internal heating element to ensure wort movement at all times. Also I didn't go the threaded option as I snapped the brown pump the first time I tried to bolt parts to it. Being 18mm inlet and outlet I was concerned if the 1/2" silicone hose would fit, It went on easy.
Priming
I placed the pump under the brew vessel, and hooked up the hoses. I opened all valves to bleed the system of air, and left it for a couple of secs once the bubbles stopped (as I do with the march pump). When I fired up the pump I had no flow, so I shut it down immediately. As soon as I turned it off more bubbles started. Upon firing it back up I had some flow but the pump was cavitating, so I shut it down a second time, more bubbles. Next time it fired up no problems and I had decent flow. Stopping and restarting the system, but keeping it full of water, I had no issues. I've never had the same issues with the march, but will just keep an eye on it. Also to be fair this is a different system against where the march pump is running, but I have got similar placing of the pump.
Noise
I think this pump is quieter than the march 809. Maybe next brew I should put the db meter against them. Both are quite enough for me.
Performance
This pump is rated at Max flow 27L/min (same as march 809) and Standard flow @ 3.1m 17L/min (march 9.5L/min).
The system it is running on, has a head of 0.75m. That is 0.75m from the outlet of the pump to the upper return line.
The inlet and outlet are spec'd at 18mm, I am only using 1/2" plumbing on my system so it will impede the flow.
Tested on my system I'm achieving 14L/min. On the same setup I got 4.5L/min from the 12v brown pump.
Comparison to march 809
The march 809 seems to have more flow once loaded up a bit in the real world. Next time I run the march pump I will try and remember to get a flow measurement from it.
The march has a polysulfone head and is rated to 121c
The kaixin has a polypropylene head and is rated to 80c
The march cost about $200 (inc post)
The kaixin cost $84 (inc post)
Overall
It's been running for the last 1hr straight, no problems.
I don't recirculate the kettle, so the extra temperature rating of the march is not a huge concern but is a nice buffer to have.
I think the kaixin is a great pump for the money, and hopefully will prove to be as reliable as the march pumps have been.
It will be interesting to see what the higher temperature rated ones will cost when they hit the market.
QldKev
who's fairly adept at designing these kind of things.
