hot water valve perm open

[Chris S]

Hi all
was hoping if someone could explain in layspeak the exact nature of my CH/HW system and the implications. Have inherited an old system in the new house and quickly ran out of money due to a quick install of a new boiler being required and so had to persist with the old setup. Have a new iflow CH motorised valve but an old Honeywell equivalent for the HW circuit. However the latter has been rigged to be permanently open. My heating engineer buddy was convinced that this was due to the piping in that half of the pipework around the boiler/cylinder not being long enough to allow for any pressure relief at the end of the timer cycle and so was wedged open in case there was some sort of bottleneck/blockage inside the motorised valve (unbelievably an isolator type valve was fitted inline in the pipework rather than the usual "red handled" one; I knew there was a pressure buildup at that stage of the cycle as I had to adjust the isolator valve to stop a vibration noise!!). So after that confusing description my question is: if the HW is permanently on in terms of the motorised valve is it just the cylinder thermostat that is controlling how much the boiler comes on for HW purposes? many thanks (PS I will obviously overhaul system after winter)

 

[Charnwood]

My heating engineer buddy..................my question is.......

My question is, why did your buddy not answer the question?

 

[CBF]

i'd get a new heating engineer buddy the lenght of pipework has nothing to do with your situation, you shouldn't have or need an isolator valve before or after the zone valve but what you should have is a auto bypass before the zone valve between the flow & ret so if the boiler has pump overrun then it has somewhere to pump, although you need one on most systems if you had a mid pos valve at least one port will always be open which it won't be on your setup

 

[stem]

I found a system that had two 2 port valves (S Plan) the original boiler didn't have a pump overrun so no by-pass was fitted. When the boiler was changed, the new one had a pump overrun and needed a by-pass so the HW valve was wedged open. It was operated like this for over 10 years! (the wiring was changed slightly too, as the valve no longer operated its internal switch for the boiler)

Some of your description sounds similar and if your conversation with your plumber buddy was in the pub late one evening, maybe something has gotten lost in the translation.

Alternatively the valve may be faulty and has been wedged open. If it has just been latched into the manually open position with its lever, that normally releases the next time the valve operates, so if it doesn't operate it won't unlatch.

 

[Nige F]

Some of your description sounds similar and if your conversation with your plumber buddy was in the BAR late one evening, maybe something has gotten lost in the translation.

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let`s keep it all American