Modulating furnace having improved low stage characteristics
US6283115A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 2000 |
| Grant date | Sep 4, 2001 |
| Priority date | — |
| Expiry date | Jul 31, 2020 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF24H3/105
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
An improved, induced-draft, gas-fired furnace which is adapted to operate at any of a high, medium and low firing rate. A pressure sensing assembly generates differential pressure signals that vary in accordance with the pressure across a heat exchanger assembly. A gas flow control assembly is responsive to the differential pressure signals, and to signals received from the furnace control circuit, to supply gas to the furnace at any of its three different firing rates, the lowest of those firing rates corresponding to a gas-air mixture which cannot be ignited. The furnace control circuit applies to the circulating air blower, and to the inducer blower, speed control signals that are so related to one another that the lowest primary wall temperature in the heat exchanger is maintained above the condensation temperature of water during steady state operation of the furnace at its low firing rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.