JPH0468261A - Hot water heating device - Google Patents

Abstract

PURPOSE:To prevent momentary idle burning by making the circulating pump to be possible to run when the water level in expansion tank becomes higher than lower water level and beginning the combustion of water heater when the water level reaches at middle. CONSTITUTION:A water level detecting device 6 is set in an expansion tank 4 and the detecting device 6 is constituted from detecting electrodes of high, middle and low water levels H,M,L respectively. When the water level of expansion tank 4 does not reach L, an automatic water supply valve 7 is opened to supply water automatically and the running of circulating pump 5 and the combustion of water heater 1 are stopped. When LON is reached, the circulating pump 5 is made to be possible to run. When MON is reached the combustion of water heater 1 is made to be possible. The automatic water supply valve 7 is closed when high water level H is reached. By making the circulating pump to be possible to run when the water level in the expansion tank reaches LON, and beginning the combustion of water heater when the water level MON is reached, the momentary idle burning caused by vibration when the water level in the expansion tank has reached at LON or lower than L can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot water heater that has a function to prevent instantaneous dry heating and circulates hot water between a water heater and a fan coil unit.

[Prior art]

Conventionally, hot water heaters perform heating operation by circulating hot water heated by a water heater through a fan coil unit.
A water level detection device detects the water level in the expansion tank installed in the heating water circulation circuit at three levels: high water level H1, medium water level M, and low water level.
It was detected in stages, and when the water level reached a low level (hereinafter referred to as LON), the circulation pump could be operated and the water heater could start combustion.

In addition, before starting heating operation, it is necessary to distribute water throughout the heating water circulation circuit, and for this purpose, combustion is carried out when the water level in the expansion tank is below the low water level (hereinafter referred to as below). It is possible to perform a heating trial run in which water flows through the entire heating water circulation circuit without heating.

[Problem to be solved by the invention]

However, in the above-mentioned conventional hot water heater, when the heating operation switch is used to fill the entire heating water circulation circuit with water, the circulation pump starts operating and the water heater burns using the LON. As a result, water is sent out from the expansion tank and the water level in the expansion tank decreases, and when it becomes less than L, the operation of the circulation pump and the combustion of the water heater are stopped, and the water level in the expansion tank decreases. There was a problem that the temperature oscillated between LON and less than L, and instantaneous dry firing occurred during this period.

An object of the present invention is to provide a hot water heater that can solve the above problems and prevent instantaneous dry heating.

[Means for Solving the Problems] In order to achieve the above object, the hot water heater of the present invention connects a water heater, a fan coil unit, and an expansion tank to form a heating water circulation circuit, and in a heating operation state, water In a hot water heater that automatically replenishes water, there is a high water level H in the expansion tank.
Equipped with a water level detection device that detects in three stages: 1 medium water level M and low water level, and the water level in the expansion tank is less than the low water level (less than L)
At the time of The water heater is designed to start combustion when the water reaches the middle water level M or higher (MON).

[Effect]

In the hot water heater of the present invention configured as described above, when heating operation is started, if there is no water in the circulation pipe or expansion tank, or if the water level in the expansion tank is less than L, the circulation pump is operated and water heating is started. It simply replenishes water automatically without burning the vessel.

When the water level in the expansion tank reaches LON, only the circulation pump starts operating, and the water in the expansion tank is pumped out to lower the water level, and when it becomes less than L, the circulation pump stops.

When this operation is repeated and water is distributed throughout the heating water circulation circuit, the water level in the expansion tank rises and reaches MON.
This starts the combustion of the water heater.

[Example〕 Embodiments of the present invention will be described based on the drawings.

In FIG. 2, to explain a hot water heater to which the present invention is applied, the water heater 1 includes a heat exchanger 10, a burner 11 arranged below the heat exchanger 10, and a control valve 12 that controls the amount of fuel gas to the burner 11. , and a combustion fan 13.

An outflow pipe 21 is connected to the hot water outlet of the heat exchanger 10, and the outflow pipe 21 is branched into a plurality of branch pipes 31.31 via the first header 30, and the branch pipes 31.31 are connected to fan coil units. 3.3 is connected to the inlet side of the heat radiation heat exchanger 32.32.

In the heat radiation heat exchanger 32.32, the heat radiation fan 33
, 33, the low-temperature water is collected from the branch pipes 34, 34 into the second header 35, and then passed through the return pipe 2.
2 to an expansion tank 4.

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

A make-up water pipe 24 and an overflow pipe 41 are connected to the expansion tank 4, and the make-up water pipe 24 is provided with an automatic make-up water valve 7.

A water level detection device 6 is disposed within the expansion tank 4, and the water level detection device G is composed of detection electrodes for a high water level H1, a medium water level M, and a low water level.

Note that 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 pump is stopped in the LON. 5, and when it reaches MON, the water heater L can start combustion, and when the high water level H is reached (hereinafter referred to as HON), the automatic make-up water valve 7 is closed.

Next, the operation will be explained with reference to the flowchart in FIG. 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 combustion of the circulation pump 5 and the water heater 1 is stopped.

When the water level in the expansion tank 4 rises and reaches LON, the operation of the circulation pump 5 is started, and when water is sent out by the circulation pump 5, the water level in the expansion tank 4 decreases and LON is reached.
When it becomes less than 1, the circulation pump 5 is stopped.

Automatic water replenishment brings the water level in the expansion tank 4 to LO again.
When reaching N, the operation of the circulation pump 5 is started, and when 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 the water returns from the return pipe 22 into the expansion tank 4, the water level in the expansion tank 4 rises, and if LON is maintained, the water circulates. Pump 5 is operated continuously.

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

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

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

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

The circulation pump can be operated when the water level in the expansion tank reaches LON, and the water heater can start combustion when the water level in the expansion tank reaches MON. It is possible to prevent instantaneous dry heating that occurs when the water level oscillates below LON and L.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operation of an embodiment of the present invention;
FIG. 2 is a schematic diagram of a heating water circuit to which the present invention is applied. 1...Water heater, 3...Fan coil unit, 4...Expansion tank, 5...Wi ring pump, 6...
Water level detection device, 7... automatic make-up water valve.

Claims (1)

[Claims] (1) In a hot water heater that has a water heater, a fan coil unit, and an expansion tank, the circulation pump can be operated when the water level in the expansion tank reaches the low water level L or above (LON), and the expansion tank A hot water heater characterized in that combustion of the water heater can be started when the water level in the water heater reaches a middle water level M or higher (MON).