Background - One morning about two weeks ago I found we had hot water in the cold water tank, so I ran off the cold (now hot) water and let the cold tank refill to try and diagnose the reason. But the cold tank has stayed cold ever since after that with nothing coming back from the hot cylinder via the feed pipe or overflow.
However, since then the HWC temperature will not rise above 50-55c despite the thermostat still being set at 65c.
It is a 200l cylinder with a 3kw immersion fed from excess solar power with a 4h boost at night.
I assumed the thermostat had failed, but after fitting a new one (tested to switch at 60-65c in a pot of hot water) there is no difference - the hot water heats until about 50c and then the controller says 'Hot' and switches off the power.
This morning, in desperation, I bypassed the themostat and lo-and-behold the water carries on heating. (I switched off when it got to 70c).
I have no idea whether the hot cold water incident and the HWC switching off early are connected, or just a coincidence, but I'm running out of ideas on what the problem might be.
Any suggestions welcome. Thanks.
However, since then the HWC temperature will not rise above 50-55c despite the thermostat still being set at 65c.
It is a 200l cylinder with a 3kw immersion fed from excess solar power with a 4h boost at night.
I assumed the thermostat had failed, but after fitting a new one (tested to switch at 60-65c in a pot of hot water) there is no difference - the hot water heats until about 50c and then the controller says 'Hot' and switches off the power.
This morning, in desperation, I bypassed the themostat and lo-and-behold the water carries on heating. (I switched off when it got to 70c).
I have no idea whether the hot cold water incident and the HWC switching off early are connected, or just a coincidence, but I'm running out of ideas on what the problem might be.
Any suggestions welcome. Thanks.