HVACopediaGlow Brand · Boiler · Freeze protection
Anti-frost pre-heat
What happens, in order
- Boiler needs power and gas; frost protection icon flashes when active (default mode 1)
- If supply, return or flue temperature falls to 50 F (10 C) the CH pump starts
- If temperature keeps dropping by a further 9 F (5 C) the burner fires at minimum power
- Burner runs until the return temperature reaches 59 F (15 C)
Timings and thresholds
| Item | Value |
|---|---|
| Pump starts | 50 F (10 C) |
| Burner fires | a further 9 F (5 C) drop |
| Burner stops | return 59 F (15 C) |
Applies to: B85, B120, B160
Models
More Glow Brand boiler sequences
- Power-up and de-air · Startup
- Ignition and retry · Ignition
- Central heat call and post purge · Heating
- Indirect tank call and priority · Domestic hot water
- Anti-legionella cycle · Other
Take it to the job
Sequences of operation, error codes and tips work offline in the HVACopedia app.
Source: Glow Brand B85/B120/B160 Installation and Operating Manual (sections 10.2, 11.7, 11.8, 11.10, 12.1). Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
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.