We had exactly the same situation on this year's section hike. I've copied my message to MSR and their reply below. This is the first problem I've had with the MiniWorks and MSR's analysis makes sense to me given the circumstances. I still like the MSR MiniWorks for my needs and plan to continue with it.
One thing I'll add is that I don't think my son was as diligent in cleaning his filter as he should have been. He described to me that he typically didn't scrub the core down but would just rinse the color off. I believe this could have resulted in the large particles getting washed off while the smaller particles were driven deeper into the core over time. I scrub my core fairly aggressively and have never had a problem, even on this hike when we pumped at the same water sources. I do boil my core after every section hike.
In the same situation, next time I would try boiling the organics out.
YMMV - I hope this helps.
______________________________
Dear Andy,
Thank you for contacting Cascade Designs Inc. and your thorough explanation of your water filter problem. It is possible that the filter had some organics which clogged it and usually scrubbing will remedy the problem. If scrubbing does not work then you can actually boil the ceramic in a pot of water.
Here are some instructions:
1. Remove ceramic element from housing.
2. Remove orange oring or orings from cartridge.
3. Place ceramic element in large pot. Cover the ceramic element completely with water (room temperature) and allow room for the water to reach a rolling boil without spilling over.
4. Bring water to a boil and allow element to remain in rolling boil for 5 minutes.
5. Turn off stove and allow water to cool before removing element.
6. Air dry ceramic element completely (3-5days).
7. Wash and dry completely all other filter parts.
8. Reassemble filter.
IMPORTANT: Remember to reinstall oring or orings.
Cascade Designs Inc.
4225 2nd Ave. South
Seattle, WA 98134
1(800)531-9531
[email protected]
Quality Innovation Service
-----Original Message-----
From: Andy
Sent: Monday, September 01, 2008 10:35 PM
To: Consumer
Subject: MSR MiniWorks EX problem
Dear MSR Customer Service,
In our family we have two MSR MiniWorks EX (me and son 1) and one
Katadyn Hiker (son 2) water filters. I've tried several water filters
over the years and decided some time ago that your MiniWorks is the
superior device. We use the filters frequently during the year and then
intensively during a two week AT section hike every year. To me, one
of the most important differentiating features of the MiniWorks over
the Katadyn is the ability to field maintain and clean the filter.
This year in the midst of our section hike, we had a very disturbing
development. My son's MiniWorks filter suddenly clogged totally. The
clogging was so severe that no water output was achieved and the
housing was building up pressure that impeded opening and could be
heard popping when finally opened.
We use a coffee filter prefilter. The affected filter core was
recently replaced and had only been cleaned a couple of times before
this happened. When we disassembled the filter, the core was slightly
discolored but not unusually so. My son who is an experienced
backpacker said that he had not filtered from any unusually dirty or
tannic contaminated sources during the hike leading up to this
incident.
Usually these filters seem to clog gradually and then we scrub away a
layer, rinse, and full flow is restored. When this happened, we
disassembled the filter and cleaned the core as ususal. The strange
thing is that we were never able to restore any water output no matter
how many times we scrubbed and rinsed the core. The core acted like it
was clogged all the way through. Finally in desperation we scraped
away significant portions of the core until finally the core failed
the minimum thickness gauge test. Even at that point no real water
output could be achieved - just a trickle. We even swapped the cores
between mine and my son's MiniWorks to prove that the core was the
problem, which did prove out.
I wanted to write to see what you think could have happened. I depend
and rely on the ability to field maintain these units and the fact
that we could not bring the MiniWorks back into any kind of even
minimal operation really hurts my confidence in backpacking with it.
Often I'm out on my own with minimal chemical backup. If we didn't
have the redundancy of the other water filters it could have been very
difficult.
I look forward to your feedback and will say that I enjoy the many MSR
products I use on my hikes.
Thank you and best regards,
Andy