Closed Combustion
Sealed combustion boilers use fans and ducted air vents which improve the performance of a Low Mass Boiler.
They also provide low NOx for emission requirements. Generally, these units also ship with upgraded ignition systems that allow for staged thermal performance for different seasonal loads.
The reason this technology was developed was to meet the newer anti-smog regulations, which were largely driven by NOx emission. These systems burn the fuel more thoroughly and release less smog.
BioTherm offers three closed combustion boiler models: HiDelta, Delta Limited, and MVB.
HiDelta
| Model Number | Full Input in BTUH | Flue Diameter | Stages |
|---|---|---|---|
| H3-HD101 | 100,000 | 4" | 2 |
| H3-HD151 | 150,000 | 4" | 2 |
| H3-HD201 | 199,000 | 5" | 2 |
| H3-HD251 | 250,000 | 5" | 2 |
| H3-HD301 | 299,000 | 5" | 2 |
| H3-HD401 | 399,000 | 5" | 2 |
| H3-302B | 300,000 | 5" | 2 |
| H3-402B | 399,000 | 6" | 2 |
| H3-502B | 500,000 | 6" | 2 |
| H3-652B | 650,000 | 8" | 2 |
| H3-752B | 700,000 | 8" | 2 |
| H3-902B | 900,000 | 8" | 2 |
| H8-992B | 990,000 | 10" | 3 |
| H9-1262B | 1,260,000 | 12" | 4 |
| H9-1532B | 1,530,000 | 12" | 4 |
| H9-1802B | 1,800,000 | 14" | 4 |
| H9-2002B | 1,999,000 | 14" | 4 |
| H9-2072B | 2,070,000 | 14" | 4 |
| H9-2342B | 2,340,000 | 16" | 4 |
Delta Limited
| Model Number | Full Input in BTUH | Flue Diameter | Stages |
|---|---|---|---|
| H4-399B | 399,000 | 6" | On/off |
| H3-499B | 500,000 | 6" | 2 |
| H3-649B | 650,000 | 8" | 2 |
| H3-749B | 750,000 | 8" | 2 |
| H3-899B | 900,000 | 8" | 2 |
| H3-989B | 990,000 | 10" | 2 |
| H8-1259B | 1,260,000 | 12" | 3 |
| H9-1529B | 1,530,000 | 12" | 4 |
| H9-1799B | 1,800,000 | 14" | 4 |
| H9-1999B | 1,999,000 | 14" | 4 |
| H9-2069B | 2,070,000 | 14" | 4 |
| H9-2339B | 2,340,000 | 16" | 4 |
MVB
| Model Number | Full Input in BTUH | Flue Diameter | Stages |
|---|---|---|---|
| H7-504A | 500,000 | 8" | Modulating |
| H7-754A | 750,000 | 10" | Modulating |
| H7-1104A | 1,100,000 | 10" | Modulating |
| H7-1504A | 1,500,000 | 12" | Modulating |
| H7-2004A | 1,999,000 | 14" | Modulating |