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Glow Brand · Boiler troubleshooting

Display normal but no domestic hot water (indirect tank)

Glow B85/B120/B160

What is going on

The boiler runs for heating but the indirect tank does not get hot.

Likely causes

  • DHW Mode not set to 1 (2.035)
  • Tank sensor not wired to terminals 5-6
  • Tank already near setpoint
  • DHW priority time ran out
  • DHW pump not running (terminals 15-16)
  • Plumbing not per the indirect tank diagram

Check in this order

  1. Confirm DHW Mode (2.035) is 1 and a tank sensor is wired per Fig. 11.12.
  2. Read the tank temperature at 1.002 and compare with the tank setpoint (2.115). A DHW call starts when the tank drops 9 F below setpoint (default 140 F).
  3. Radiator icon flashing the DHW priority time (2.043) may have expired. Cycle power and consider a longer priority time or higher setpoint.
  4. Faucet icon flashing confirm the DHW circulator runs on terminals 15 and 16.
  5. Check the piping against Figure 6.4.
  6. Any DHW setting above 120 F needs a thermostatic mixing valve.

Applies to: B85, B120, B160 (NG and LP)

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Source: Glow Brand B85/B120/B160 Installation & Operation Manual V20231025, 13.2.3 p.68. 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.