UK Manufactured Unvented Hot Water Cylinder Installation Guide
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Testing
If there is no hot water you can carry out several tests with your multimeter to decide which component is
faulty.
First remove the cover for the wiring and then check for voltage across the live and neutral terminals on the
element. If you get a reading the element is faulty (power going through thermostat so stat is working).
Next, check whether the thermostat is working by connecting your multimeter to the live out of the thermo-
stat, if there is no reading the thermostat is faulty.
If the water is getting extremely hot the thermostat is stuck in the
‘ON’ position and will need to be replaced.
Safety
•
Disconnect the immersion from the mains electrical supply before removing any covers.
•
Do not attempt to replace the immersion heater(s) with alternatives to those recommended by JOULE.
•
Do not bypass the Thermal Cut-Out(s) in any circumstances.
Replacing The Immersion
First task is to isolate the power. Immersion heaters are rated at 3kW and require their own 16A or 20A dou-
ble pole isolation switch. Turn off the power from the isolation switch and remove the fuse. Next turn off the
water to the tank.
Drain the water from the tank via the drain cock using a hose. Remove the immersion using an immersion
spanner. Thread in the replacement immersion heater creating the seal using a rubber o-ring. Slot the im-
mersion heater into the hole with the washer and make sure the threads are lined up correctly. Tighten with
whichever spanner you are using, taking care not to over tighten and risk damaging the cylinder.
Open the taps up and turn the cold water supply back on. When water starts to come out of the taps shut
them off and check for leaks. If all is good wire up the immersion heater, checking that your connections are
good. Fit the cap on the immersion and turn the power back on.
If the immersion is connected to a booster switch turn it on and check that it heats up. Economy 7 immersion
heaters will only turn on at set times during the night and cannot be altered so check the following morning
to see if the water has heated up properly.
