Polaris was working fine until the back-up valve case cracked. Strange place to crack - the nut holding the smaller half to the larger half cracked around the whole nut and the threaded part of the larger half cracked directly under that. The crack was through the whole case and almost all the way around the circumference.
Anyway, I had another case from a previous repair. Found it, put the old valve into it and put the Polaris back into operation. Unexpectedly, especially since it had been working just minutes ago, the back-up valve failed. Ordered a new one; awaiting delivery.
Here's the question: Can you repair a back-up valve? It looks fine. The gears all seem to mesh & turn. Hate having to spend around $50 (w/o case) for a new one if there's another solution.