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Glow Brand · Boiler troubleshooting

Heating system preparation and water quality

C95 & C140

What is going on

Stainless steel heat exchanger is damaged by corrosion, debris and hard water. Prepare and protect the heating loop before startup.

Likely causes

  • Debris, flux, solder or scale left in the system.
  • Dissolved oxygen from tap water and frequent make-up water.
  • Hard make-up water causing calcium deposits in the heat exchanger.
  • Leaks that introduce fresh oxygen into the system.

Check in this order

  1. Flush the entire system before connecting the boiler and repeat as needed.
  2. Use a suitable cleaning agent for new and retrofit systems. Use a heavier cleaner for heavy lime scale or sludge.
  3. Make sure the system is watertight before filling.
  4. Use only approved piping black malleable iron, flexible corrugated stainless steel, copper, or PEX/PERT rated for heating with an oxygen barrier for the heating loop.
  5. Add an inhibitor to the heating water.
  6. Limit make-up water additions and treat hard make-up water.
  7. Failure to follow these steps voids the warranty and can cause premature heat exchanger failure.

Applies to: Boiler heating loop preparation

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Source: Glow Brand C95 & C140 installation & operating manual, p. 32. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.