Operating instructions
78
User Interface Display
Explanation
Boiler Conguration
Two pump modes are available:
1. 
Pump Mode = 0 ‘CH or CH&DHW’
• In this mode either CH or DHW pump terminal is energized 
depending on type of demand (CH or DHW).
• CH and DHW pumps are never energized at the same time.
• In the case of simultaneous call for both CH and DHW, the 
energized pump depends on whether the boiler is currently 
supplying CH or DHW demand. Refer to DHW Priority 
settings below.
• This is typical of hydronic system design with separate CH 
and DHW Pumps.
2. 
Pump Mode = 4 ‘System Pump’
• In this mode only one external system pump is installed in 
hydronic system. This pump will energize independent of 
type of demand (CH or DHW).
• Connect this pump to CH/System Pump electrical terminal 
block. See page 35 for diagram.
• DHW pump terminal does not function.
• This is typical of hydronic system design which utilizes zone 
valves for all CH zones and DHW indirect tank.
Note:
• Pump Mode selection depends on electrical and 
hydronic system design. Please refer to sections 5 
and 8 for recommended hydronic piping and electrical 
congurations.
• Internal heat exchanger pump is energized anytime 
demand exists regardless of Pump Mode setting or type 
of demand (CH or DHW).
'Service Reminder’ feature allows the installer to enable or 
disable a service reminder notication on the User Interface at a 
predened interval .
Service reminder does not affect operation of boiler in any way. 
It is only a reminder to End User that routine preventative 
maintenance is required by qualied service technician.
Allowed Range: 1 to 999 days 
APPENDIX A - CONTROL MODULE










