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7.2 OVERHEAT LOCK-OUT & RE-SETTING
Central heating overheat.
If the boiler detects a overheat condition of 100ºC (80ºC if adapted floor heating) in the central heating circuit a safety
thermal limit switch will operate and switch the boiler off disabling all functions including DHW production.
The cause of the overheat should be investigated.
The safety limit switch is on the right underside of the boiler and will require re-setting manually by following the procedure
shown:
Unscrew & remove the black cap and push the small pin behind it until you hear a click. The limiter will not re-set until the
temperature in the heating header drops below 100°C or 80°C if the boiler is adapted for radiant floor heating.
Domestic Hot Water overheat.
As with the heating circuit a second thermal limit switch, situated on the left underside of the boiler, will operate if a
overheat condition (80ºC) is detected in the DHW circuit and switch the boiler off disabling all functions including central
heating.
The cause should be investigated and the above procedure followed to re-set the DHW limit switch.
Summary of Contents for MATTIRA MAC15B
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