Abstract: A compact, highly flexible and efficient, multi-positionable, multi-dimensional and multi-stage gas-fired heat exchanger system as described. The system is connectable in a forced air duct regardless of the angular position and size of the duct. The heat exchanger comprises one or more heat transfer tubes which are shaped and dimensioned as dictated by the customized use of the heat exchanger. The tubes are secured to a support panel as well as the gas burner associated with each of the inlet openings of the tubes. A position orientable gas valve is secured to a gas distribution manifold. A turbulator may be associated with at least some of the tubes to cause turbulence in the hot combustion flow in each of the tubes to modify the efficiency in heat transfer along one or more sections of the tubes by directing hot combustion gas along an inner circumferential wall of the tubes.

Abstract: An automatic modulating regulator device and method of operation for use with a non-electrical hot water heat source supplied by a pressurized water supply. The hot water heat source has a hot water circuit to pump hot water to heat exchange elements. The regulator device comprises a valve which when a power failure occurs changes to a normally open state. The regulator device is adapted to be connected to a hot water return conduit of the hot water circuit. A self-powered thermostatic valve is responsive to a temperature sensor and modulates the flow of hot water returned through the regulator device. A flow restrictor is connected downstream of the regulator device for releasing controlled quantities of water from the return hot water conduit to a drain.

Abstract: An external gas-fired heater for heating a water/glycol fluid is comprised of a housing having a combustion chamber therein. The chamber has a coil through which the water/glycol fluid is circulated and heated by a cylindrical gas burner disposed inside the coil with the coil spaced thereabout. The housing is adapted for mounting outside a building to which the heated fluid is convected for heat exchange with heating devices contained within the building. A cover is removably secured to the housing for access to the internal heater devices and is equipped to convect air within the housing for the air-gas mixing blower. Quick connect couplings permit the housing to be easily removed and replaced, if necessary. The cover also provides ease of access to the heater devices for servicing or replacement.