circuit for "central heating"

[Eyckmans Albert]

Hello,



Does anyone knows how the hardware of a regulator to start
modulating the gasburner of central heating works.

I mean modulating on the boilers own thermostate (set on 60°C).

The boiler measuring points are suction and discharge temperature.

The signal to start modulating go to the boilerfan speedregulator which on
his turn regulate the gasvalve and this mixture goes through a venturi to
the premix burner.

I want to know how the controller works, the electronic circuit, which
building blocks ( IC etc) are possibly used to make it work.

The control unit used in my cv boiler (which control a lot more than the
position of the gasvalve during modulating) is from
Honeywell (MCBA 1461 V3.1) but the agent in my country won't give any
information on it.

Albert

 

[Paul Hovnanian P.E.]

Hello,

Does anyone knows how the hardware of a regulator to start
modulating the gasburner of central heating works.

I mean modulating on the boilers own thermostate (set on 60°C).

The boiler measuring points are suction and discharge temperature.

The signal to start modulating go to the boilerfan speedregulator which on
his turn regulate the gasvalve and this mixture goes through a venturi to
the premix burner.

I want to know how the controller works, the electronic circuit, which
building blocks ( IC etc) are possibly used to make it work.

The control unit used in my cv boiler (which control a lot more than the
position of the gasvalve during modulating) is from
Honeywell (MCBA 1461 V3.1) but the agent in my country won't give any
information on it.

Probably because of the liability involved should someone mess around
with this system and blow a building up.

Most simple gas furnaces have burners that are either on or off. Sensors
detect certain prerequisite conditions necessary for safe operation
(pilot/ignition source on, proper flue draft, etc.) and then command the
gas valve open. Other parameters are monitored to ensure continued safe
burner operation (heat exchanger overtemp., backflow of combustion
gasses, etc.) and will shut the furnace down if out of bounds conditions
are detected.

I'm sure that there are more sophisticated control systems for larger
(commercial, industrial, etc.) type installations. But I'm guessing that
the Honeywell rep. figures that anyone qualified to work on one of these
systems will know where to get maintenance and repair data.