HVACopediaFlowMax · Combi boiler
E14 Air pressure switch tripped
What the control is telling you
Listed only in the 120 diagnostics list. The 120 troubleshooting table puts air pressure switch faults under E02 instead; checks below come from that E02 entry.
Applies to: FLOWMAX-90, FLOWMAX-120
Likely causes
- Air pressure switch faulty
- Intake or exhaust vent blocked
- Air pressure switch wiring loose
Test and repair steps
- Inspect the intake and exhaust vent pipes and terminals for blockage and clear them.
- Check the vent length is within the 100 ft maximum equivalent length (each 90° short elbow = 7.5 ft, each 45° = 2.5 ft).
- Check the air pressure switch wiring and sensing hoses.
- Replace the switch if it does not close with the fan running and venting clear.
Settings for these units
Installation clearances · FlowMax condensing combi (FLOWMAX-90/120)
| Location | Service clearance (in) | To combustibles |
|---|---|---|
| X (side) | 0 | 0 in |
| Y (side) | 0 | 0 in |
| L | 16 | - |
| H | 24 | - |
| A (above) | 12 | 0 in from jacket top |
| B (below) | 12 | - |
| Front | - | 0 in |
| Rear | - | 0 in |
Wall-mount on a flat, solid vertical wall that can carry the weight.
Letters follow fig. 1 of the manual; L and H are the clearance zone in front/around the unit as drawn.
Hot water scald risk by temperature · FlowMax condensing combi (FLOWMAX-90/120)
| Temperature setting | Time to 2nd/3rd degree burn (adult skin) |
|---|---|
| Over 170°F | Nearly instantaneous |
| 160°F | About 1/2 second |
| 150°F | About 1-1/2 seconds |
| 140°F | Less than 5 seconds |
| 130°F | About 30 seconds |
| 120°F or less | More than 5 minutes |
120°F lowers scald risk; children, elderly and disabled people burn faster.
Fit a tempering (mixing) valve if water is stored or set hotter, e.g. with parameter 1 = 03 (up to 160°F).
Models that show this code
2 models in FlowMax condensing combi (FLOWMAX-90/120)
Other codes on the same units
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Source: FlowMax FLOWMAX-120 Instruction Manual, 6.11 Diagnostics error code list, p.67. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
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.