HVACopediaGlow Brand · Boiler troubleshooting
Display normal but no domestic hot water
What is going on
Heating works or display is fine but there is no hot water.
Check in this order
- No tank DHW mode (2.035) must be 5. Check DHW flow (1.062). The burner needs more than 0.5 gpm (1.9 l/m) to start. If flow is low, check supply, the cold inlet filter screen and the flow sensor wiring; replace the flow sensor if needed.
- Compare DHW setpoint (0.048) with DHW temperature (1.002). Burner fires when temperature is under setpoint with flow. Suggested setpoint 125 F (52 C); raise at 2.048.
- Tank with sensor mode 1, sensor wired per Fig. 11.12, tank setpoint at 2.115 (default 140 F, demand starts 9 F below).
- Tank with aquastat mode 2 unless using the alternate connection, aquastat wired per Fig. 11.12, max tank setpoint 135 F.
- If the radiator symbol flashes, DHW priority time may have run out. Cycle power and raise 2.043 or the tank setpoint.
- If the faucet symbol flashes with a tank, check the DHW circulator on terminals 9 and 10.
- Check plumbing matches Fig. 6.3 or 6.5.
Applies to: C95, C140 (NG and LP)
More boiler guides
Related
Glow Brand error codes · Glow Brand parts · Glow Brand tips · Calculators and reference tables
Take it to the job
All guides, error codes and tips work offline in the HVACopedia app.
Source: Glow Brand C95 & C140 Installation & Operation Manual V.01282025 , Sec. 13.2 p.73. 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.