JPH0730924B2 - Hot water heater - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hot water heater having a momentary emptying prevention function and circulating hot water between a water heater and a fan coil unit.

[Prior art]

Conventionally, in a hot water heater that performs heating operation by circulating hot water heated by a water heater to a fan coil unit,
The water level in the expansion tank provided in the heating water circulation circuit is determined by the water level detection device to be three levels of high water level H, medium water level M, and low water level L.
When the water was detected at the stage, and the water was in the low order L (hereinafter referred to as L ON), the circulation pump could be operated and the combustion of the water heater could be started.

In addition, before starting the heating operation, it is necessary to spread water over the entire heating water circulation circuit, and for this purpose, combustion is performed when the water level in the expansion tank is lower than the low water level L (hereinafter referred to as less than L). Instead, it is possible to perform a heating trial run in which water flows through the heating water circulation circuit.

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional hot water heater, when the heating operation switch is used to fill water in the entire heating water circulation circuit, the circulation is started to operate the circulation pump and start the combustion of the water heater at L ON. The water is sent from the expansion tank by the pump, and the water level in the expansion tank drops. When the water level falls below L, the operation of the circulation pump and the combustion of the water heater are stopped. Oscillates between L ON and less than L, and there is a problem that instantaneous boiling is performed during this period.

An object of the present invention is to provide a hot water heater capable of solving the above-mentioned problems and preventing instantaneous air heating.

[Means for Solving the Problems]

In order to achieve the above object, the hot water heater of the present invention is a hot water heater that forms a heating water circulation circuit by connecting a water heater, a fan coil unit, and an expansion tank to automatically supply water in a heating operation state. , A water level detecting device for detecting three levels of high water level H, medium water level M, and low water level L in the expansion tank is provided, and when the water level in the expansion tank is less than the low water level L (less than L), the circulation pump is operated and The combustion of the water heater is stopped, and the circulation pump can be operated when the water level in the expansion tank reaches the low water level L or more (L ON).
When the water level in the expansion tank reaches the medium water level M or higher (M ON), combustion of the water heater can be started.

[Action]

In the hot water heater of the present invention configured as described above, when heating operation is started, when there is no water in the circulation pipe or the expansion tank, or when the water level in the expansion tank is less than L, operation of the circulation pump and water heating It does not burn the vessel but simply supplies water automatically.

When the water level in the expansion tank becomes L ON, only the circulation pump starts operation, the water in the expansion tank is sent out and the water level drops, and when it becomes less than L, the circulation pump stops.

When water is distributed to the entire heating water circulation circuit by repeating this operation, when the water level in the expansion tank rises to M ON, the combustion of the water heater is started.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 2, a hot water heater to which the present invention is applied will be described. The water heater 1 includes a heat exchanger 10, a burner 11 disposed below the heat exchanger 10, and a control valve 1 for controlling the combustion gas amount of the burner 11.
2 and a combustion fan 13.

The outgoing pipe 21 is connected to the hot water outlet side outlet of the heat exchanger 10, and the outgoing pipe 21 is provided with a plurality of branch pipes 31, 31 via the first header 30.
The branch pipes 31 and 31 are connected to the inlet sides of the heat radiating heat exchangers 32 and 32 of the fan coil units 3 and 3, respectively.

In the heat radiating heat exchangers 32, 32, the low temperature water after heating the air supplied by the heat radiating fans 33, 33 is collected from the branch pipes 34, 34 to the second header 35, and is returned from the return pipe 22 to the expansion tank 4
Sent to.

The low temperature water in the expansion tank 4 is transferred from the water inlet pipe 23 to the heat exchanger 10 of the water heater 1 by the circulation pump 5 provided in the water inlet pipe 23.
Sent to the cold water side inlet of.

The expansion tank 4 includes a makeup water pipe 24 and an overflow pipe 41.
Is connected, and the makeup water pipe 24 is provided with an automatic makeup water valve 7.

A water level detection device 6 is disposed in the expansion tank 4, and the water level detection device 6 is composed of high water level H, medium water level M, and low water level L detection electrodes.

When the water level in the expansion tank 4 is less than L, the automatic replenishment water valve 7 is opened to start automatic replenishment of water, the operation of the circulation pump 5 and the combustion of the water heater 1 are stopped, and the circulation is performed at L ON. The pump 5 can be operated, and when it becomes M ON, the combustion of the water heater 1 can be started, and when the high water level H is reached (hereinafter referred to as H ON), the automatic makeup water valve 7 is closed.

Next, the operation will be described with reference to the flowchart of FIG. 1. When the heating operation switch is turned on when there is no water in the entire heating water circulation circuit including the expansion tank or the circulation pipe (for example, immediately after installation), the expansion tank 4 Since the water level inside is less than L, the automatic replenishment water valve 7 is opened and water is automatically replenished, but at this time, the circulation pump 5 and the water heater 1 have stopped burning.

When the water level in the expansion tank 4 rises and reaches L ON, the operation of the circulation pump 5 is started, and when water is sent out by the expansion pump 5, the water level in the expansion tank 4 decreases, and when the water level is less than L, circulation occurs. The pump 5 is stopped.

The water level in the expansion tank 4 becomes L ON again due to automatic water supply.
When it reaches, the operation of the circulation pump 5 is started, and when the water is sent out by the circulation pump 5 and the water level in the expansion tank 4 becomes less than L, the circulation pump 5 is stopped.

By repeating this operation alternately, water spreads throughout the heating water circulation circuit, and when water returns from the return pipe 22 into the expansion tank 4, the water level in the expansion tank 4 rises and L ON is maintained. The circulation pump 5 is continuously operated.

When the water level in the expansion tank 4 further rises and reaches M ON,
The combustion of the water heater 1 is started, and the combustion operation is continued while controlling the hot water temperature.

When the water level in the expansion tank 4 rises and reaches H ON, the automatic replenishment water valve 7 is closed and water replenishment is stopped.

When the water level in the expansion tank 4 drops again to less than L during the heating operation, the combustion of the water heater 1 is stopped, the automatic replenishment water valve 7 is opened, and the automatic replenishment of water is restarted.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

The circulation pump can be operated when the water level in the expansion tank reaches L ON, and the combustion of the water heater can be started when the water level in the expansion tank reaches M ON. It is possible to prevent the instantaneous water heating that occurs when the water level inside vibrates between L ON and less than L ON.

[Brief description of drawings]

FIG. 1 is a flow chart showing the operation of the embodiment of the present invention,
FIG. 2 is a schematic configuration diagram of a heating water circuit to which the present invention is applied. 1 ... Water heater, 3 ... Fan coil unit, 4 ...
Expansion tank, 5 ... Circulation pump, 6 ... Water level detector,
7 ... Automatic replenishment water valve.

Claims (1)

[Claims] 1. In a hot water heater having a water heater, a fan coil unit and an expansion tank, a circulation pump can be operated when the water level in the expansion tank reaches a low water level L or more (L ON). The hot water heater is characterized in that the combustion of the water heater can be started when the water level in the expansion tank reaches the medium water level M or higher (M ON).