"Jerry." wrote in message
...
Anyone know of any issues with Honeywell 3 port mid position valves, i.e.
installation, location or in service problems etc., I've had three or four
go faulty in the last 4 years since the system (and I hasten to add) was
professionally installed and it sounds like I might be approaching another
!

It's either been problems with the valve it's self or the motor drive not
operating (opening the required port(s)) and thus causing the boiler to
overheat and cut out due to there being no flow - and causing hot water
and
steam to be forced up into the boiler feed / expansion tank :~(


this last part dosnt make sense as the valve will never shut both ports no
flow will be caused by a pump failure
if the valve is not powered the hw port is open if it is the ch port will
open or a blockage in the system
phil n