Please read before proceeding – Lochinvar 400-801 User Manual
Page 4

4
Please read before proceeding
When servicing boiler –
• To avoid electric shock, disconnect electrical supply 
 before performing maintenance.
• To avoid severe burns, allow boiler to cool before 
 performing maintenance.
Boiler operation –
• Do not block flow of combustion or ventilation air to 
 the boiler.
• Should overheating occur or gas supply fail to shut off, 
 do not turn off or disconnect electrical supply to 
 circulator. Instead, shut off the gas supply at a location 
 external to the appliance.
• Do not use this boiler if any part has been under water. 
 The possible damage to a flooded appliance can be 
 extensive and present numerous safety hazards. Any 
 appliance that has been under water must be replaced.
Boiler water –
•
Thoroughly flush the system (without boiler
 connected) to remove sediment. The high-efficiency 
 heat exchanger can be damaged by build-up or 
 corrosion due to sediment.
• Do not use petroleum-based cleaning or sealing 
 compounds in the boiler system. Gaskets and seals in 
 the system may be damaged. This can result in 
 substantial property damage.
• Do not use “homemade cures” or “boiler patent 
 medicines”. Serious damage to the boiler, personnel, 
 and/or property may result.
• Continual fresh make-up water will reduce boiler life. 
 Mineral buildup in the heat exchanger reduces heat 
 transfer, overheats the stainless steel heat exchanger, and 
 causes failure. Addition of oxygen carried in by makeup 
 water can cause internal corrosion. Leaks in boiler 
 piping must be repaired at once to prevent the 
 introduction of makeup water.
Freeze protection fluids –
• NEVER use automotive antifreeze. Use only inhibited 
 propylene glycol solutions which are specifically 
 formulated for hydronic systems. Ethylene glycol is 
 toxic and can attack gaskets and seals used in hydronic 
 systems.
Service Manual
