no hot water from taps, indirect system. Open vented

[nenevall]

i` noticed yesterday that my HW from taps was tepid, not hot as it was few days prev, the CH pump running okay, rads nice and hot...

Switching the motorised valve into manual i felt some resistance where it felt like it as trying to go back to auto, pipes seem pretty hot feeding into and out of the storage tank?

yet still 1 hour later, no real change in hot water temp.

Any Suggestions, hints?

 

[nenevall]

couples hours later, hot water now coming through...

looks like a faulty control zone valve!

 

[nenevall]

ok so we sort of have hot water, but its no where as hot as it used to be...

more lukewarm / tepid...

feeling the pipes going into the cylinder the input from the 3 way valve is pretty warm to the touch, the output is stone cold.. which would suggest the heat is transferring into the coil and water?

the only thing i noticed is the temp of the pipes leading into the 3 way valve from the circulating pump is very hot... ouchie if you hold onto it. as is the 22m pipe going to the rads, the pipe going to the cyclinders is hot but not as hot as the other 2 pipes..... by the time it goes to the first floor to the cylinder its noticeable cooler...

is it possible the 3 way valve is somehow restricting the flow enough to cause water temp to drop?

 

[Hugh Jaleak]

Pipe feeding cylinder coil from 3 way valve should be as hot as the input pipe from the boiler when HW is selected (or valve is locked open manually). It doesn't appear to be from your description so either valve not opening to HW port properly or cylinder coil airlocked/blocked.

If the pipe is rising from the valve to the cylinder there should be a method for venting air out of the coil. I'd check for an airlock first.