Hot water air locked on solar thermal system

BEC · Feb 5, 2015

Hi there,
I installed a solar thermal system to a property in the summer and changed an old vented cylinder over a two coil cylinder (also vented). Has worked fine until last couple of weeks when the customer is complaining of air locks in his hot water taps. My first thoughts are that the temp stat might have gone and the water is getting far too hot (he does say that it's very hot when it comes out) and blowing off causing an air lock in the system.

Any other thoughts on this?

BEC

gassafe · Feb 5, 2015

Are you referring to the temp stat that goes into the cylinder from the solar? I can't imagine at this time of year that the solar is getting too hot!!

I guess they've been using the boiler to heat the top coil in this weather so maybe check the setting on that thermostat, check immersion is turned off, or maybe the ball valve is playing up in the header tank, not refilling fast enough etc...

BEC · Feb 5, 2015

gassafe said:
Are you referring to the temp stat that goes into the cylinder from the solar? I can't imagine at this time of year that the solar is getting too hot!!

I guess they've been using the boiler to heat the top coil in this weather so maybe check the setting on that thermostat, check immersion is turned off, or maybe the ball valve is playing up in the header tank, not refilling fast enough etc...

Thanks for the reply. Yes, it will be getting topped up by their existing oil boiler so I was thinking of the main thermostat on the cylinder. I hadn't thought of the ball valve on the header tank so will check that although I don't think it will be this because their cold water pressure is fine (also fed from header tank).