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7.2 OVERHEAT LOCK-OUT & RE-SETTING
Central heating overheat.
If the boiler detects an 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
an 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.
7.3 HEATING SYSTEM FLOW SWITCH – E3 ERROR & SYSTEM BY-PASS REQUIREMENTS
If the error E3 appears on the display, the flow switch has detected insufficient water flow in the heating circuit
and heat production is disabled to protect the boiler from overheating.
A 7l/min flow rate is required. The possible causes for this condition are:
- Insufficient water pressure in the heating system requiring re-filling to 1.5bar
- Pump not circulating or seized. Check as shown (Sect 5.5)
- Blockage in heating circuit from debris or a foreign object in the boiler or pipe-work.
- Insufficient flow rate caused by restrictions such as insufficient size pipe-work, too many bends or isolation valves
with restricted bore.
- Closed radiator valves (Thermostatic). It may be sufficient to maintain one radiator with permanently open valves
however it is recommended the fitting of an automatic by-pass valve. This type of valve modulates open when
necessary to ensure that the appropriate minimum flow rate is maintained through the boiler, at all other times it
is closed thus preventing unnecessary and wasteful circulation through the bypass and the boiler.
7.4 CHECKING RATED HEAT OUTPUT
It is possible to check the actual heat power output configuration that is set on the boiler and also the
modulated operating output at that moment.
Press the
button for three seconds.
The heating display will show
followed by the temperature value of the return probe of the heating
circuit.
On pushing
button the display will show
followed by the value of the limited maximum output
according to the tables (see 5.1).
On pushing
button again the display will show
followed by the actual modulated output power at
that moment.
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