Abstract: A heat exchanger includes front and rear walls forming a flue gas space such that a fluid flowing through a channel formed in the front and rear walls can exchange heat with flue gas in the flue gas space, in use. An entirety of the back wall extends along a first plane, and the back wall is provided with a back fin. The front wall includes a lower portion extending upwardly along the back wall, and an upper portion extending upwardly from an upper end of the lower portion and outwardly away from the back wall to form a combustion space of a flammable gas between the upper portion and the back wall. The upper portion is provided with a front fin. The front and back fins are arranged symmetrically with respect to a virtual line along which the flammable gas is to be injected into the combustion space.

Abstract: A heat exchanger system includes a heat exchange main unit having a gas channel and a fluid channel configured such that a fluid in the fluid channel can exchange heat with a flue gas in the gas channel, a housing, a drain collecting part arranged to collect condensate from the flue gas, and a siphon attached to the drain collecting part to prevent release of the flue gas from a condensate outlet. The siphon has a tubular body, first portion having a condensate inlet, and second portion having the condensate outlet and an operation member. When the tubular body is attached to the drain collecting part, the first portion is connected to the drain collecting part, the first and second portions can be at least partially located inside and outside the housing, and the operation member can be located outside the housing. The first and second portions are detachably attached.

Abstract: A heat exchange system includes a heat exchange main unit having a gas channel and a fluid channel configured such that a fluid in the fluid channel can exchange heat with a flue gas in the gas channel, a housing, a drain collecting part arranged to collect condensate from the flue gas, and a siphon detachably attached to the drain collecting part to prevent release of the flue gas from a condensate outlet formed in the siphon. The siphon has a tubular body, a condensate inlet formed on one end side, and the condensate outlet formed on an other end side. The tubular body has an attaching part to detachably attach the tubular body to the drain collecting part through a hole formed within a wall of the housing, and a grip located outside the housing when the tubular body is attached to the drain collecting part.

Abstract: A heat exchanger includes front and back walls forming a flue gas space such that a fluid flowing through a channel formed in the front and back walls can exchange heat with flue gas in the flue gas space, in use. The front wall includes a lower portion extending along the back wall, and an upper portion extending upwardly from an upper end of the lower portion and outwardly away from the back wall to form a combustion space of a flammable gas between the upper portion and the back wall. A length of the upper portion along a longitudinal direction thereof is longer than a length of the lower portion along a longitudinal direction thereof.

Abstract: A heat exchanger includes front and rear walls forming a flue gas space such that a fluid flowing through a channel formed in the front and rear walls can exchange heat with flue gas in the flue gas space, in use. An entirety of the back wall extends along a first plane, and the back wall is provided with a back fin. The front wall includes a lower portion extending upwardly along the back wall, and an upper portion extending upwardly from an upper end of the lower portion and outwardly away from the back wall to form a combustion space of a flammable gas between the upper portion and the back wall. The upper portion is provided with a front fin. The front and back fins are arranged symmetrically with respect to a virtual line along which the flammable gas is to be injected into the combustion space.

Abstract: A heat exchanger system includes a heat exchange main unit having a gas channel and a fluid channel configured such that a fluid in the fluid channel can exchange heat with a flue gas in the gas channel, a housing, a drain collecting part arranged to collect condensate from the flue gas, and a siphon attached to the drain collecting part to prevent release of the flue gas from a condensate outlet. The siphon has a tubular body, first portion having a condensate inlet, and second portion having the condensate outlet and an operation member. When the tubular body is attached to the drain collecting part, the first portion is connected to the drain collecting part, the first and second portions can be at least partially located inside and outside the housing, and the operation member can be located outside the housing. The first and second portions are detachably attached.

Abstract: A heat exchange system includes a heat exchange main unit having a gas channel and a fluid channel configured such that a fluid in the fluid channel can exchange heat with a flue gas in the gas channel, a housing, a drain collecting part arranged to collect condensate from the flue gas, and a siphon detachably attached to the drain collecting part to prevent release of the flue gas from a condensate outlet formed in the siphon. The siphon has a tubular body, a condensate inlet formed on one end side, and the condensate outlet formed on an other end side. The tubular body has an attaching part to detachably attach the tubular body to the drain collecting part through a hole formed within a wall of the housing, and a grip located outside the housing when the tubular body is attached to the drain collecting part.

Abstract: A heat exchanger includes front and back walls forming a flue gas space such that a fluid flowing through a channel formed in the front and back walls can exchange heat with flue gas in the flue gas space, in use. The front wall includes a lower portion extending along the back wall, and an upper portion extending upwardly from an upper end of the lower portion and outwardly away from the back wall to form a combustion space of a flammable gas between the upper portion and the back wall. A length of the upper portion along a longitudinal direction thereof is longer than a length of the lower portion along a longitudinal direction thereof.