HVACopediaGlow Brand · Boiler
Loc 16 Flue temperature too high
What the control is telling you
Exhaust temperature went above the limit set by the appliance setting: 149 F (65 C) with PVC venting or 194 F (90 C) with CPVC.
Applies to: B85, B120, B160 (NG and LP)
Likely causes
- Blocked exhaust or intake
- Dust, lint or oil drawn into the combustion air
- Dirty combustion chamber or scaled heat exchanger
- Wrong indirect tank piping, sensor or aquastat
- Secondary pump not running
- Parameters 2.003/2.024/2.091/2.115 set above what the vent material allows
Test and repair steps
- Check intake and exhaust for blockage.
- Make sure the combustion air is clean.
- Clean the combustion chamber or descale the heat exchanger, then run a combustion analysis.
- If an indirect tank is used, check its piping, sensor/aquastat and secondary pump.
- Confirm the CH and DHW setpoint limits match the vent material (PVC = 140 F max; CPVC needed above that with parameter 2.138 set to 52-55).
Settings for these units
Maintenance intervals · Glow B85/B120/B160
| Item | When |
|---|---|
| Annual inspection by a technician | Every year (warranty) |
| Relief valve try-lever test | Annually |
| LWCO test | Annually |
| Condensate trap clean | Annually (14.3) |
| Heat exchanger combustion-side wash | Annually or when combustion drifts (14.4) |
| Burner door silicone gasket | Replace if damaged or after 2 years |
| Service reminder | 2.203 on, interval 2.204 (default 1000 days) |
Operating pressure should sit 5 psi under the relief valve rating (max 25 psig on a 30 psi valve); water never above 180 F.
Models that show this code
3 models in Glow B85/B120/B160
Other codes on the same units
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Source: Glow Brand B85/B120/B160 Installation & Operation Manual V20231025, Table 12.1 p.63. Summarized in our own words; check the original manual for your model.
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