My brother-inlaw has problems with his hot water supply. The furnace
heats the house OK but the hot water, supplied by the furnace, seems to
work best only when the furnace is also heating the house. It seems like
the furnace has the wrong control, one for a furnace that only
supplies home heat. Assuming that the furnace has the proper control
does it seem that the control has failed in some way such that the
furnace will cool all the way down when there is no demand for home heat
and thereby allowing the heat exchanger coils to no longer heat the
domestic hot water?

Thank you for any ideas,
andy

"andy everett" wrote in message
news:xXnWh.104$Zm.10@trndny03...
My brother-inlaw has problems with his hot water supply. The furnace heats
the house OK but the hot water, supplied by the furnace, seems to work
best only when the furnace is also heating the house. It seems like the
furnace has the wrong control, one for a furnace that only supplies home
heat. Assuming that the furnace has the proper control does it seem that
the control has failed in some way such that the furnace will cool all the
way down when there is no demand for home heat and thereby allowing the
heat exchanger coils to no longer heat the domestic hot water?

Thank you for any ideas,
andy

Start at the beginning. Furnaces heat air. Boilers heat water. If he
truly has a furnace, it will not heat his water. He probably has a boiler.
Did the boiler once work properly, now it does not? You imply it has the
wrong control. If it worked in the past and no longer works, you have a
defective control, most likely. If it is a new install, it is possible that
some control is lacking or not properly wired. In that case, call the
installer. If something is not working properly on an older unit, any
competent service technician can find and fix the problem. In this case, it
is probably not a DIY job to repair it.

On Apr 21, 9:02 am, andy everett wrote:
My brother-inlaw has problems with his hot water supply. The furnace
heats the house OK but the hot water, supplied by the furnace, seems to
work best only when the furnace is also heating the house. It seems like
the furnace has the wrong control, one for a furnace that only
supplies home heat. Assuming that the furnace has the proper control
does it seem that the control has failed in some way such that the
furnace will cool all the way down when there is no demand for home heat
and thereby allowing the heat exchanger coils to no longer heat the
domestic hot water?

Thank you for any ideas,
andy

There should be an aquastat somewhere on the boiler. It's basically a
thermostat for the hot water. There should be a dial on it for you to
adjust, normally hot water is set to about 150. Either it's set to
low, or the aquastat and/or the wiring is not working right. that's
why you only get hot water when the boiler comes on to heat the house.

If it's a fairly modern boiler, with a domestic coil, it will probably have
a triple aquastat relay mounted right on the front of the unit. It'll
probably say Honeywell on it. If you have one like this, it will have two
adjustable dials inside, One for high temperature cut out, and one for low
temperature cut in. This type of boiler is designed to maintain a tank of
hot water for both domestic and heat. If the low temp cut in is set to low,
it won't fire up unless the heat thermostat is raised. Check to see that the
high temp cut out is set for 180 and the low temp cut in is set for 150




"andy everett" wrote in message
news:xXnWh.104$Zm.10@trndny03...
My brother-inlaw has problems with his hot water supply. The furnace heats
the house OK but the hot water, supplied by the furnace, seems to work
best only when the furnace is also heating the house. It seems like the
furnace has the wrong control, one for a furnace that only supplies home
heat. Assuming that the furnace has the proper control does it seem that
the control has failed in some way such that the furnace will cool all the
way down when there is no demand for home heat and thereby allowing the
heat exchanger coils to no longer heat the domestic hot water?

Thank you for any ideas,
andy