Thermaflow TH12 - Checking the Elements; Checking Circuit Breakers; Checking the Contactor; Check the Operation of the AQUA STAT

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Checking the elements
Check the continuity between live and neutral terminals on the element. Replace the element if there is
no continuity.
Checking circuit breakers
Switch each circuit breaker off in turn and check that continuity is broken to each element.
Checking the contactor
Turn the main isolator off (this should be situated adjacent to the boiler) you should hear a dull thump
from the enclosure marked number 3 on the boiler schematic diagram 1.8.1. This indicates that the
contactor has disconnected the circuit to the MCB and in turn the four heating elements. Turn the main
isolator on and off a few times and listen for this noise. This will indicate correct operation of the
contactor.
Check the operation of the AQUA STAT
The Aqua Stat is positioned above the bottom element on the boiler.
Make sure the external controls are
calling for heat.
Turn the dial on the thermostat up and down and listen for a small click. As you turn the
thermostat dial up and down check if the central heating pump, (positioned on the right side of the
unit) is switching
on and off. If this is the case, this indicates correct operation of the thermostat.