Help! How water cyclinder open vent pipe

[81ll]

I have an issue where the HWC (Hot Water Cyclinder) open vent pipe is dripping occasionally into the CWSC (Cold Water Storage Cistern) in the loft. Which is causing the overflow from the CWSC to drip.

The HWC Stat temp was sent to 55 degrees.

I have turned down the temp for the heating system and hoping this cures the issue.

Any suggestions what the issue could be?

 

[Ch4 plumbing]

Faulty cylinder stat?
Faulty immersion stat maybe?

 

[Simon F]

Is the overflowing water hot/cold?
any mixer taps?
how hot is the hot water, same as stat or hotter?
how high is the overflow?
how quickly does the cold tank empty, is there a blockage in the cold feed to cylinder?

 

[81ll]

The immersion heater is not one.

The overflowing water is hot.
There are mixer taps, if it was them i believe it would drip all the time.
how hot is the hot water, same as stat or hotter? Need to check this.
The overflow is a good height, I thought about bending the float bar but that isn't really a proper fix (i think)
how quickly does the cold tank empty, is there a blockage in the cold feed to cylinder? The cold tank does not empty, no cold feed to the cylinder is not blocked.

 

[JCSPLUMBING]

I'd say cylinder stat is buggered.

 

[solutions]

Does the vent pipe rise vertical out of the cylinder to the storage cistern or is there a horizontal section at the top of the cylinder first?

Still most likely a failed thermostat. Check your immersion is off so you can exclude that.