DE3832320A1 - Method for regulating a central-heating boiler - Google Patents

Abstract

In order to obtain a maximum saving of energy, but eliminate the occurrence of condensate, a regulating method is proposed in which a mixing valve (16) is switched completely from the return pipe (17) to the flow pipe (15) and the burner (18) is run on full load in a starting circuit until a minimum value of the boiler water temperature (at thermostat 13) slightly above the dew point is reached, with a low or normal heat demand, i.e. at desired flow values below the set value of sensor (20), the desired flow temperature is regulated by the mixing valve (16), and with a high heat demand, i.e. at desired flow values above the set value at sensor (20), the mixing valve (16) is switched completely towards the heating boiler and the burner (18) is run in modulating fashion with adjusted burner load. <IMAGE>

Description

The invention relates to a method according to the preamble of Claim 1.

Central heating boilers used to be high enough Temperature operated above the dew point. The setting the desired flow temperature was carried out using a mixer by adding an appropriate amount of colder return running water to the hotter flow. Such a regulation was included quite high energy losses of the high-temperature boiler connected.

The boilers are used today to avoid energy losses smoothly regulated to temperature ranges below the dew point. The desired flow temperature is immediately in the heating boiler set. Can on a downstream mixer usually be dispensed with. Appropriate measures are taken against the resulting condensate. These can be on the water side, on the heating side, in the operating mode burner and material selection.

There are thus two different boiler regulations opposite, the sliding mode of operation due to the has achieved significant energy savings. Doing so tries to damage due to the formation of condensate by suitable Prevent measures.

A boiler regulation is to be created with which one achieved the highest possible energy savings, the emergence of However, condensate is almost completely avoided.

The control method according to the invention consists of the in the characteristic Signs of the patent claim measures.

Essential for avoiding condensation in the boiler is compliance with a minimum boiler water temperature temperature above the dew point. This is according to the invention but only slightly above the dew point and not on one for all cases of sufficient height. Because of the special Switching of the mixing valve and the burner becomes the minimum value reached as quickly as possible during start-up. The rapid passage through the condensation area prevented a larger amount of condensate.  

With low and normal heat requirements, i.e. H. if the weather set flow setpoints below the minimum boiler value water temperature, the flow temperature (for heating circle) regulated in the usual way. Because the minimum However, the energy losses are relatively low quite low. In any case, the formation of condensate is removed because the minimum temperature is above the dew point.

When there is a high demand for heat, i. H. if the weather-related pre run setpoints are above the minimum value, the lead temperature (towards the heating circuit) in the now general slidably regulated in the boiler. The mixing valve is open to the boiler. The burner is controlled directly. Its modulating mode of operation ensures the desired Boiler (flow) temperature. Since this is always only on the required value, energy losses are largely eliminated switches. The value is well above the specified min minimum value. So there is no condensate.

The invention represents a sensible combination of the two known control methods. Compliance with a relative low, but above the dew point minimum valuable, limits energy losses and avoids condensation sat formation. The special regulation of the boiler water temperature uses above this minimum value when there is a high demand for heat known advantages of sliding control.

The drawing represents one in a single figure Longitudinal section through a boiler including one Control schemes as an embodiment of the invention.

In a reverse combustion chamber 1 , the heating gases are passed to a front turning chamber 2 and from there through smoke pipes 3 through the water space 4, 4 ' to the rear exhaust gas collector 5 . Impressions 6, 6 ' in the smoke pipes 3 serve to increase the turbulence and adapt the flow cross-section to the heating gas temperatures. Short-circuit smoke pipes 7 with an embossments 9 lead from the bottom 8 of the reversing combustion chamber 1 to the exhaust manifold 5 . When the temperature falls below a limit in the exhaust pipe 10 , a shut-off flap 12 resting on an end ring 11 is opened. The exhaust gas temperature is raised by the short-circuit flow.

In the start-up or heating phase of the boiler, a thermostat 13 bridged with its end lying above the dew point switching point the heating circuit flow sensor 14 in the flow line 15 and 16 on the mixing valve entirely from the return line 17 to the feed line 15 °. The burner 18 runs at full load until the set minimum temperature is reached in the thermostat 13 .

When the switching point of the thermostat 13 is reached and at low temperature setpoints for sensor 14 below a temperature set on sensor 20 , sensor 20 is switched to controller 21 and modulating burner 18 maintains the minimum temperature set on sensor 20 in the boiler. The set value of the sensor 20 is just above the switching point of the thermostat 13 . At the same time, the controller 19 is effective, which mixes the return flow 15 with the return flow 15 via the mixing valve 16 and thus regulates the flow temperature in accordance with the provision by sensor 14 .

When operating with high heat requirements and high setpoints for sensor 14 above the set value of sensor 20 , controller 21 is switched to sensor 14 and sensor 20 is deactivated. The specified setpoint of the flow temperature at sensor 14 is now driven directly by the burner 18 . The mixing valve 16 is opened all the way to the boiler.

Claims (1)

Method for controlling a central heating boiler with a mixing valve between the return line and the supply line while maintaining a minimum value of the boiler water temperature, characterized in that
that the mixing valve ( 16 ) is switched entirely from the return line ( 17 ) to the supply line ( 15 ) and the burner ( 18 ) is operated at full load (slightly above the dew point of the water temperature in the boiler with thermostat ( 13 ) and the burner ( 18 ) is operated at full load (start-up circuit) ;
that at setpoints of the flow temperature at sensor ( 14 ) below the minimum value of the boiler water temperature at sensor ( 20 ), the desired flow temperature is regulated by the mixing valve ( 16 ) and the burner ( 18 ) is switched on if necessary to maintain the minimum value (low and normal heat is required) );
and that at setpoints of the flow temperature at the sensor ( 14 ) above the minimum value of the boiler water temperature at the sensor ( 20 ), the mixing valve ( 16 ) switches the return ( 17 ) completely to the heating boiler and the burner (18) modulating depending on the desired setpoint Flow temperature (at sensor 14 ) is driven.