Problem with Coleman Hot Water on Demand system

Has anyone had a problem with their Coleman Hot Water on Demand system? After one year of use, (great use - the thing has worked perfectly), it seems as though the on-off temperature adjustment knob has become stuck in a postion such that the battery is constantly draining, and I can't get the unit to come on. I've so far resisted the temptation to try the brute force method of trying to turn the knob back, but the spirit is weak and I don't know how long I can hold out without hope of some other way of fixing it. I've looked for a Coleman service center, but the only one in NY is in Jamestown, which is so far from Long Island that it is almost in Ohio. Anyone have any experience of working on these units that might be relevant to my problem?

I had also been keeping mine in the original box so it wouldn't get slammed around. Last weekend, I took it to Oyster Bay, it's first trip without the box because I wasn't bringing the trailer and was short on space. Possibly something hit it. It had been charged before I put it away for the winter, but had run down while in storage. If I hook it up to the charger, the charging indicator lights and eventually turns green to indicate a full charge. As soon as the charger is disconnected, the light switches to the low battery indicator. If I push the knob in and turn it, I can hear the relay clicking, and the unit fires up, but then cuts out immediately. The pump doesn't seem to be working at all. (I have checked to make sure the right side is up.) I have removed the knob from its mounting, but since I don't know what the innards looked like to begin with, I can't tell if anything looks wrong. It may be time to place a call to the company and see if they can help: I would really be annoyed with myself if I screwed up a $175 piece of equipment out of a stubborn refusal to get help with it.