SWMBO went to make a pot of coffee with our Bunn coffeemaker and
reported to me that the water which flowed through the ground coffee was
I checked for the obvious and then drained the unit and took it down to
my basement shop for a look see.
I quickly found the problem was an open 141 degree C thermal fuse
mounted on top of the heater tank. That fuse was the first thing in
series with the hot side of the power cord and fed everything else in
But, I was surprised to find that there wasn't just one thermal fuse
there but two identical ones in series, clamped to the top of the tank
within a millimeter of each other.
I resisted the temptation to bypass the open thermal fuse and was
pleased to find that the Radio Shack store a quarter mile from our home
stocked them. Fifteen minutes later I was back home with a new $1.99
thermal fuse, installed it and the Bunn was back in business.
But why does Bunn use TWO identical thermal fuses in series? Are those
little suckers so unreliable that they felt the need to use two in case
one of them failed to open when the tank temperature soared because of a
My curious mind wants to know.
(W1BSV + Brass Rat '57 EE)
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