Method for the predictive maintenance of primary circuit components of a boiler

Method for controlling a gas boiler, said boiler comprising:

• a primary circuit for the heating of heat transfer fluid, in turn comprising:
• a combustion chamber housing a primary exchanger and a burner fed by an air/gas mix provided by a fan and by a gas valve,
• feeding and return conduits of the heat transfer fluid flowing in said primary circuit, respectively adapted to lead said fluid to the heating bodies of the heating system and vice versa by a circulating pump,
• inlet and return conduits for deviating said heat transfer fluid towards a secondary exchanger in its primary side,
• a secondary circuit for the heating of sanitary water, comprising:
• said secondary exchanger,
• feeding and return conduits, respectively adapted to lead said cold water in an inlet of the secondary side of the secondary heat exchanger and said hot sanitary water from said secondary side of the secondary heat exchanger towards the user,
• a three-way baffle valve adapted to switch the path of said heat transfer fluid:
• towards said heating bodies of the heating system via an output, in such case said boiler being in HEA operating mode to heat said fluid,
• or towards said secondary circuit, in such case said boiler being in DHW operating mode to heat said sanitary water,
• a control unit adapted to manage the steps of said method and to exchange information with sensor means adapted to measure the flow rate Q of said heat transfer fluid flowing in said primary circuit,
• said control method monitoring the efficiency state of said primary exchanger, and/or said primary-side secondary exchanger, and/or said pump through a periodic control of the flow rate values Q, Q-r, Q.dhw, and/or Q.hea of the heat transfer fluid flowing in said primary circuit, said flow rate values Q, Q-r, Q.dhw, and/or Q.hea being provided by said sensor means and processed by said control unit,
• wherein said control method provides for the output of signals W.dhw, W.20, W.30-10, W.10, and/or W.30 representative of the loss of efficiency of said primary exchanger and/or primary-side secondary exchanger and/or pump when said flow rate values Q, Q-r, Q.dhw, and/or Q.hea reduces below the reference flow rate values Q.dhw-rif and/or Q.hea-rif, pre-stored in said control unit,
• said flow rate values Q, Q-r, Q.dhw, and/or Q.hea being provided by:
• a flow meter or other equivalent type of flow rate sensor, located on said primary circuit,
• and/or a smart pump,
• and/or sensor means detecting one or more physical quantities from which said flow rate values Q, Q-r, Q.dhw, and/or Q.hea are calculated,
• said control method comprising a first part “method M.dhw” wherein:
• the boiler is operated in a DHW operating mode;
• the pump is operated at the maximum rotation speed;
• the control unit contains in memory at least:
• a reference flow rate value Q.dhw-rif, representative of the optimal flow rate of the boiler in said DHW operating mode,
• a threshold value ΔQ.dhw-rif consisting in the reduction of the flow rate value Q, Q-r, and/or Q.dhw detected with respect to said reference flow rate value Q.dhw-rif, said threshold value ΔQ.dhw-rif being representative of an anomalous reduction of the flow rate value Q, Q-r, and/or Q.dhw,
• a value Fl.max representative of the maximum number of consecutive exceedances of said threshold value ΔQ.dhw-rif;
• said reference flow rate value Q.dhw-rif is compared with repeated readings of said flow rate value Q, Q-r, and/or Q.dhw flowing in the primary circuit with the boiler in said DHW operating mode, and if:
• said threshold value ΔQ.dhw-rif is exceeded for a number of consecutive times equal to said value Fl.max, then said control unit provides for a final step END.dhw_1 for the output of an alarm signal W.dhw, representative of the loss of efficiency of said primary exchanger and/or primary-side secondary exchanger and/or pump, otherwise said control unit provides for a final step (END.dhw_2), stopping said first part “method M.dhw” and setting up to repeat it periodically.