HVACopediaGlow Brand · Boiler
AttE 204 Outdoor sensor open or shorted
What the control is telling you
The outdoor temperature sensor on terminals 3 and 4 reads open or shorted. The boiler keeps running without outdoor reset.
Applies to: B85, B120, B160 (NG and LP)
Likely causes
- Sensor wiring
- Failed outdoor sensor
- CH mode 1 or 2 selected with no sensor fitted
Test and repair steps
- Measure the sensor about 10,000 ohm at 77 F (25 C).
- If the resistance is right, check the wiring to terminals 3 and 4.
- Replace the sensor, or set CH mode 0 if no outdoor sensor is used.
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 12.3 p.66. Summarized in our own words; check the original manual for your model.
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