That was why I was asking the OP where his domestic hot water was coming
from. What you describe is the domestic coil used as a heat loop, which is
fine if the loop is not to demanding. If the demand is great, that coil
couldn't produce enough hot water to heat the loop, which is where a side
arm tank comes in. Instead of a small coil sitting in the boiler, a large
coil sits in this auxiliary tank, with an aquastat controlling the temp in
the tank


"Mikepier" wrote in message
oups.com...

RBM (remove this) wrote:
The heat exchanger is a tank with a coil in it and uses two circulators.
One
circulator moves dirty boiler water through the coil in the tank and
back,
that one would get clogged if there was to much sludge. The other
circulator
moves the heat exchanger tank water through the heating pipes and back
into
the tank


I had something different. I had a Weil Mclein steam boiler, that had a
spot to insert a coil to make hot water. The coil ( or heat exchanger)
is in direct contact with the boiler water. There was an inlet and an
outlet on this coil. Only this was not used for domestic hot water, it
was used for hydronic baseboard. We just attached a circulator, a
regulator valve for the water supply, and an aquastat. It was just one
circulator, not 2. so this is why I asked how sludge can be an issue
because the actual boiler water never comes in contact with baseboard
water in my set-up. But I have seen the setup you are describing in
other houses.