These units were installed in 2009. I have them installed in a eight unit apartment building and these were very effective at keeping top with the demand. I recently switched to each unit having their own hot water heaters so I have no need for these. They have been serviced regularly so these should last for many years to come at a fraction of the price it would cost to replace. Even if you don't need them now, I would buy and store, just in case at this price.
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