Hot water not hot enough

[izzy eckerslike]

Our hot water is not getting hot enough anymore, we have old gas fired indirect gravity hot water & pumped heating, I think that maybe the heating circuit is robbing the water tank of hot water, The 2 flow pipes from the boiler both go to a connection on the tank & share the expansion pipe. the heating pipe then carries on around the house.

When switching on hot water only it seems the thermostat switches it off before it gets hot enough, however the heating pipe gets very hot where the expansion gravity forces it along parts of the system
does it sound like a blockage in the tank coil/fitting?
Our water is not really hard but our kettle does fur up a little

 

[bathjobby]

When switching on hot water only it seems the thermostat switches it off before it gets hot enough

Seems to answer your question ! If you haven't changed the temp setting on it and it is switching the boiler off before water is getting up to temp, change it, a few £s.

 

[sooey]

It sounds like a blocked cold feed and not enough water in the system. Check the float valve in the header tank aand drain some water from the system to see if the tank starts to fill.

 

[izzy eckerslike]

When switching on hot water only it seems the thermostat switches it off before it gets hot enough

Seems to answer your question ! If you haven't changed the temp setting on it and it is switching the boiler off before water is getting up to temp, change it, a few £s.

I have upped the temp to full with little effect, the fact that water is not really hot when the heating is on also points to sme other fault.

Quote:
It sounds like a blocked cold feed and not enough water in the system. Check the float valve in the header tank and drain some water from the system to see if the tank starts to fill. :Quote

I have drained the heating circuit & refilled it , not sure if this would also empty the flow & return to the hot tank

How can I be sure that there is no air trapped in the coil that goes thru the tank ? Is there a means of bleeding it or is air just pushed out thru the expansion pipe