DISPLAY CAUSE
E03 Flow temperature over 100°C while boiler is not in
operation (stand-by)
E56 Heating flow temperature probe in open circuit
E66 Heating flow temperature probe short-circuited
E04 Domestic hot water temperature probe in open circuit
E05 Domestic hot water temperature probe in short circuit
E08 Under floor heating temperature probe in open circuit
E20 Flame detected with gas valve closed
E21 Error in the electrical connection (live and neutral crossed)
E22 Problem with the 50Hz power supply
E23 Flame detection electrode short-circuited
E64 Heating return temperature probe in open circuit
E74 Heating return temperature probe in short circuit
E99 Problem within the electronic system
There follows a description of the safety functions that most influence the behaviour of the boiler.
1.FLOW SWITCH. At the beginning of every ignition sequence, the P.C.B. checks the operation of the main circuit flow switch. Initially, the pump is off and the flow switch must be open (not giving consent); if this does not occur within the space of a minute, the system carries out a shutdown. When the flow switch is open, the pump is turned on and within one minute the flow switch must close; if it does not do so, the monitoring mechanism shuts down the boiler (with the pump off).
During normal operation, the flow switch must remain closed; if it opens for over two seconds, the boiler shuts down, then the monitoring mechanism will attempt to turn it back on.
2.FAN. On ignition, the fan must rotate at the correct speed, otherwise the boiler will not attempt to turn itself on. During operation, the fan rotates at the speed set by the control P.C.B.; if the number of rotations deviates by more than 300 rpm from this setting, the boiler shuts off.
3.OVERHEATING. This device shuts down the boiler in the event that the primary circuit reaches a temperature that exceeds 100°C.
The operation of the overheat monitoring mechanism also includes the following precautionary measures:
-After every ignition, the system flow temperature or the flow/return difference must increase by 3°C in 20 seconds. Until an increase of 3°C is reached, the boiler remains at the ignition power. If the increase in temperature does not come about, the boiler shuts down and will not attempt to re-ignite until the flow temperature is below 50°C. If after three attempts the temperature does not increase, the boiler shuts down.
-Before the boiler attempts ignition, the system flow/return temperature difference must be below 20°C. In order for a successive attempt at ignition to be carried out, the system must register that once every 2 hours the flow/return temperature difference is below 5°C.
-If, during operation the return temperature becomes greater than the flow temperature by more than 5°C, the boiler shuts down immediately.
4.DAILY TEST. In order to prevent the shutdown of the components, the boiler carries out a self-diagnosing test every 24 hours: the pump turns on for 3 seconds and the diverter valve moves.
5.ANTI-FROSTDEVICE. The boiler is fitted with an anti-frost device consisting of three separate functions:
-Monitoring of the system flow temperature: if this temperature goes below 5°C, the pump turns on (heating system circulation). If the temperature goes below 2°C, the boiler turns on at the minimum power and remains on until the return temperature is over 10°C.
-Outdoor sensor installed: the pump turns on if the external
temperature goes below -3°C, it turns off when the external temperatures raises above -1°C.
-Continuous operation of the pump: select by means of jumper 4
(see paragraph 3.6.6.).
NOTE: In all cases, the circulation takes place in the heating system. The anti-frost device activates only when (with the boiler operating correctly):
-the system pressure is correct;
-the boiler is electrically powered;
-there is a supply of gas.
6.ANTI-SCALEDEVICE. When producing domestic hot water, the burner shuts off whenever the output temperature of the hot water exceeds 62°C or the flow temperature of the primary circuit exceeds 72°C. It will not turn on if the temperature of the primary circuit is greater than 72°C.
3.9.COMBUSTION ANALYSIS
The boiler is designed to allow for easy analysis of
the products of combustion.
Using the special traps, it is possible to detect the temperature of the burnt gas, the combustion air, the concentrations of O2,
CO2, etc.
The maximum heating power test conditions may be optimised by turning the selector knob “C” to the flue test position.
3.5.DRAINING
The draining of the heating system must be carried out as follows:
-Turn off the boiler and the bipolar switch;
-Loosen the automatic air release valve (27);
-Open the system's discharge valve (18) and gather the water that comes out in a container;
-Empty out from the lowest points of the system (where provided).
If the system is to be left active in areas where the room temperature may go below 0°C during winter, it is recommended that anti-freeze liquid be added to the water in the heating system in order to avoid the need for repeated draining.
Draining the domestic hot water system
Every time that there is a danger of freezing, the domestic hot water system must be drained as follows:
-close the water mains stop-cock;
-open all the hot and cold water outlets;
-empty out from the lowest points (where provided).
