Operating instructions
7
3.1 Component Listing - Refer to diagrams on 
following pages.
1. 
User Interface Displays information regarding boiler 
condition. Allows adjustment of boiler operating 
parameters. NOTE: Does not replace thermostat used 
to control central heating space.
2. 
Combustion Air Inlet (2"/3") See section 6.
3. 
Return Water From Heating System (In) 
Connection supplied at bottom of boiler. See section 5.
4. 
Low Voltage Terminal Strip Connection of all low 
voltage wiring, including thermostat. 
5. 
Igniter
6. 
Flame Sensor 
7. 
Sight Glass Permits observation of burner ame.
8. 
Burner (see page 40)
9. 
Heat Exchanger 
10. 
Condensate Collector
11. 
Return Water Temperature Sensor
12. 
Drain Valve (see page 14)
13. 
Internal Primary Loop Ball Valve 
14. 
Supply Water Outlet to Heating System (Out) 
Connections supplied for connecting from bottom of 
boiler. See section 5.
15. 
Vent Temperature Sensor 
16. 
Condensate Drain  Boiler produces a liquid 
(condensate) as a by-product of combustion. Condensate 
must be piped to appropriate drain. See section 6.
17. 
Heat Exchanger Pump 
18. 
Gas Shutoff Valve  Fuel supply isolation during 
servicing. See section 7
19. 
Combustion Air Blower Delivers proper quantity of 
combustion air, receives fuel from gas valve, mixes air 
and fuel sending mixture to burner for combustion.
20. 
Gas (Control) Valve Delivers proper quantity of fuel 
to Combustion Air Blower. See section 7. 
21. 
Supply Water Temperature Sensor and High Limit 
Switch 
22. 
Low Water Cutoff Senses inadequate quantity of 
water. Turns off boiler before damage can occur.
23. 
Safety Relief Valve Factory supplied, Field installed. 
See section 5.
24. 
High Voltage Junction Box For connection of 120V 
components. See section 8.
25. 
Vent Connector  See section 6.
26. 
Gas Connection See section 7.
27. 
Wall Hanging Support Bracket (see page 12) 
Integral to boiler. Allows wall mounting when used 
with supplied wall mounting bracket. See section 4.
28. 
Air Vent
29. 
Boiler Control Module 
30. 
Lower Jacket Panel Gently pull upward then forward 
to access. 
31. 
Transformer Supplies 24V power to low water cutoff. 
32. 
Flue Air Mixture Pressure Test Port - Not available 
on all models.
33. 
Combustion Analysis Test Port 
34. 
Internal Pump Relay - Not available on all models.
35. 
Heat Exchanger Surface Temperature Switch
36. 
ASME Plate
3 - COMPONENT LISTING










