HVACopediaFlowMax combi boiler error codes
13 codes with causes and test steps, plus 2 settings tables.
| Code | Meaning | Severity |
|---|---|---|
| 31 | Incompatible remote control | Low |
| E01 | Ignition / ionization lockout (no flame) | High |
| E02 | Safety (overheat) thermostat or air pressure switch tripped | High |
| E03 | Flue gas thermostat / exhaust thermofuse tripped | High |
| E05 | Heating (supply) sensor fault | Medium |
| E06 | Domestic hot water (DHW) sensor fault | Medium |
| E12 | DHW storage tank (cylinder) sensor fault | Medium |
| E14 | Air pressure switch tripped | High |
| E16 | Fan (blower) fault | High |
| E22 | Parameter programming request | Medium |
| E35 | Flame detection fault (false flame) | High |
| E42 | Fan speed control board fault | High |
| H2O | Low water pressure in heating circuit | Medium |
Settings and specs
Installation clearances
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.
- Closet installation: 0 in front; alcove allowed.
Source: FlowMax FLOWMAX-120 Instruction Manual (ManualsLib 769807), 3.3 Installing the water heater fig. 1 and item d, p.25; Warning label p.15
Hot water scald risk by temperature
Specifications · 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).
Source: FlowMax FLOWMAX-90 User Manual (ManualsLib 763385), Danger - Table Risk of Scalds (image), p.7; FlowMax FLOWMAX-120 Instruction Manual (ManualsLib 769807), same table (image), p.14
Models covered
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.