Troubleshooting

A quick reference table for troubleshooting issues when installing and servicing a Mixergy cylinder.

Mixergy cylinders

Fault Possible Cause Solution
Milky / cloudy water  Oxygenated Water Water from any pressurized system will release oxygen bubbles when flowing. The bubbles will settle out.
No hot water flow  Cold main off Check and open stopcock.
Strainer blocked in inlet control group Isolate water supply, strip and clean.
Inlet control group may be fitted incorrectly Check and refit if required.
Water escaping from the case unit Compression fitting on pipework not sealing  Check / remake joint.
Leaking cylinder  Isolate supply and contact Mixergy technical support via phone (01865 884 343) or through our Website
Cold water at hot taps.  Heat source not working 

Check heat source - consult boiler / heat pump / solar manufacturer’s instructions. 

The immersion heater is not switched on or the cutout has triggered  Check / reset.
Motorised valve fault  Check plumbing / wiring to motorized valve. 
Circulating pump fault   Check pump and consult manufacturer’s instructions.  
Cut-out in dual stat has operated  Reset and investigate cause. 

Water discharges from expansion relief valve 

If continual, pressure reducing valve (part of inlet control group) may not be operating correctly.  Check outlet pressure from inlet control is 3 bar. 
If continual - expansion relief valve seat may be dirty or damaged  Remove cartridge - check seat, clean and renew if necessary. 
If intermittent - expansion vessel charge may have reduced / bladder perished Check pressure in expansion vessel. Recharge to 3bar if necessary. If bladder perished replace vessel. 
Unit is being back pressurized. 

With cylinder cold check pressure in cylinder. If this is the same as the incoming mains pressure then you are getting a back feed. Install a balanced cold supply.

Hot water discharges from temperature & pressure relief valve

Unit has overheated - thermal controls have failed 

Switched off power to boiler / heat pump and immersion heater. Leave water supply on. Wait until discharge stops. Isolate water supply and replace if faulty.

Noise during hot water draw off - typically worse in the morning 

Expansion vessel over pressurised

Check pressure adjust to 3 bar.

Hot or warm water from cold tap 

If tap runs cold after a minute or so the pipe may be picking up heat from hot pipework or heating pipework. 

Insulate / re-route. 

Low Pressure

Service valve not fully open 

Ensure service valve is fully open.

Partially blocked strainer

Check/clean strainer in pressure reducing valve.

Restricted delivery pipework

Replace damaged or old pipework. 

Low mains pressure 

Check incoming mains pressure or discuss with local water supplier.

Water not hot enough

Boiler not providing enough heat

Ensure boiler thermostat is set to above 65°C

Cylinder thermostat settings incorrect

Adjust thermostat to between 55°C & 65°C

Status LED codes

Flashing green

System OK

Solid green / red

System updating. Do not turn power off

Very slow flashing red every 2 seconds – temperature sensor issue

Check temperature sensor

Slow flashing red once a second – no gauge detected

Check gauge is plugged in correctly

Fast flashing red twice a second – energy measurement issue

Contact Mixergy technical support via phone (01865 884 343) or through our Website

Very fast flashing red, five times a second – unable to detect the presence of the current reader if Mixergy Solar X

Check the wiring between the cylinder controller, diverter, current reader and current clamp

Very fast flashing red, five times a second – main processor issue

Contact Mixergy technical support via phone (01865 884 343) or through our Website.

Solar X

Fault Possible Fault Solution
Cylinder always switches the immersion on to full power when diverting Current clamp has been installed in the wrong direction Current clamp must be attached around the neutral cable on the incoming mains supply with the arrow pointing towards the incoming supply main fuse.
Rapidly flashing red light on the side of the cylinder
controller
Cylinder unable to detect the presence of the current reader Check the wiring between the cylinder controller, diverter and current clamp.

PV Switch

Fault Possible Fault Solution
3rd party solar diverter not working correctly Solar diverter is unable to supply heat to the cylinder Check the solar diverter is setup correctly according to
manufacturer's instructions
Check the immersion heater thermostat is adjusted to max
Check that the cylinder is not entirely full of hot water (i.e. 100% charged). If the cylinder is full of hot water, drain the cylinder down 20-30% and repeat the commissioning steps.
RCD tripping  RCD is tripping when the cylinder is switched on  Check all mains wiring to the PV switch, diverter and cylinder immersion. 

Heat Pump Kit

Fault Possible Fault Solution
Heat pump DHW sensor reading incorrect value or giving an error code The heat pump interface DIP switches set incorrectly 
Check resistance reading by measuring between the COM and HOT or COLD
Reset DIP switches to correct resistance. Confirm by measuring between the COM and HOT or COLD
Immersion heater being energised when a call for heat Cylinder hasn’t been set to operate with the default heat source set as ‘heat pump’ Check/reset default heat source to ‘heat pump’
Cylinder is charging slowly via heat pump Heat exchanger circulator pump not running or set incorrectly Check the heat exchanger circulator pump is running and set to 3