====== Immergas Zeus 24 Maior schematics and repairing ======

===== Schematics - Reference =====

==== From the user manual ====


{{:notes:schema_manuale.png|}}

LEGENDA:
  * B1   -  Sonda NTC mandata
  * B2   -  Sonda NTC sanitario
  * CAR  -  Comando amico remoto (optional)
  * E1-E2 -  Candelette accensione
  * E3   -  Candeletta rilevazione
  * E4   -  Termostato di sicurezza
  * H1   -  Led alimentazione valvola gas
  * H2   -  Led segnalazione blocco
  * H3   -  Led presenza rete
  * M1   -  Circolatore
  * M2   -  Ventilatore fumi
  * M3   -  Motorino tre vie
  * S4   -  Micro pressostato fumi
  * S5   -  Interruttore generale
  * S7   -  Micro pressostato impianto
  * TA   -  Termostato ambiente On/Off (optional)
  * X20  -  Ponte inibizione TA o CAR
  * Y1   -  Valvola gas
  * Y2   -  Modulatore valvola gas


==== Details of MAIN REGULATION BOARD ====

X2 has the following links : 11-10 , 9-8, 7-6 . Between the links are optocouplers that feel the power to the GAS VALVE and/or the overheat.

X7, 17 and 16 are switched together through a relays contact. This gives the consent to the Burner Board.

==== Details of BURNER CONTROL BOARD ====

{{:notes:schema_burner.png|}}

==== The whole ignition path schematic ====

This schematic is a view of the whole circuit that controls ignition. It comprehends parts of the two boards and other components and adopts some semplifications.

{{:notes:schema_tot.png?1000|}}

===== The repairing =====

The common problems concerns relays and capacitors on the Burner Board.

The cap. after R33, parallel to coil of "central" relais, was dried in my case, thus relay oscillated at 50Hz and damaged its contacts.
Replacing the cap. (10uF/63V) and the relais (OMRON 48V), had the furnace back alive.