JP3608022B2 - Freezing prevention device for hot water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a freeze prevention device for a hot water heater, and more particularly, to a freeze prevention device for a hot water heater that performs a freeze prevention combustion operation.
[0002]
[Prior art]
Conventionally, hot water heaters have an ambient temperature detection thermistor (F-point thermistor) installed at an appropriate place, and perform a freeze prevention operation by detecting that the ambient temperature has decreased.
For example, as shown in FIG. 6, the conventional hot water heater has a water heater 1, a heating forward pipe 3 is connected to the outlet side of the heat exchanger 2 of the water heater 1, and the inlet of the heat exchanger 2. The heating return pipe 4 is connected to the side, and drain plugs 31 and 41 are provided at the ends of both pipes 3 and 4.
The heating return pipe 4 is provided with a circulation pump 5 and an expansion tank 7, and a drain pipe 6 having a drain plug 61 is branched. The expansion tank 7 includes a water refill pipe 71, an overflow pipe 72, and a water level detection. And an electrode 73.
A gas conduit 81 is connected to the combustor 8 having the ignition electrode 9 and the flame detection electrode 10, and a gas governor 12 and a gas electromagnetic valve 13 are provided in the gas conduit 81.
A control device 14 such as a computer is provided, and is provided in a heating temperature thermistor (high temperature thermistor) 15 and an airing safety device 16 provided in the heating forward pipe 3 and a combustion fan 11 communicated with the lower part of the water heater 1. The rotation speed sensor 17, the overheat prevention device 18 provided in the vicinity of the casing of the water heater 1, and an ambient temperature detection thermistor (F point thermistor) provided at a suitable location outside the casing of the water heater 1 to detect the ambient temperature. ) 19 is connected to the control device 14.
[0003]
The freezing prevention operation will be described. In FIG. 4, the detected temperature t of the ambient temperature detection thermistor 19 is equal to or lower than the freezing prevention temperature to (for example, to = 7 ° C.) or the detected temperature T of the heating temperature thermistor 15 is freezing prevention. When the temperature is equal to or lower than t ₁ (for example, t ₁ = 7 ° C.), the circulation pump 5 is turned on to start the operation, the combustion of the combustor 8 is started to start the antifreezing operation, and the heating temperature thermistor 15 Is detected to be equal to or higher than a preset anti-freezing set temperature t _s (for example, t _s = 19 ° C.) and the combustor 8 is turned off to stop the combustion. When a transition is made to the post-pump operation to continue the operation and a predetermined time s (for example, s = 5 minutes) has elapsed, the operation of the circulation pump 5 is stopped and the freeze prevention operation is terminated, and the ambient temperature detection Whether the detected temperature t of the thermistor 19 is below freezing prevention temperature-to, or detected temperature T of the heating temperature thermistor 15 begins to freeze prevention operation again becomes below freezing prevention temperature t _1.
[0004]
Further, when the heating temperature thermistor 15 is heated by the heating operation, it takes time to cool the heating temperature thermistor 15, the heating temperature thermistor 15 cannot detect a temperature drop, and the presence of the ambient temperature detection thermistor 19 is indispensable. In the case where the ambient temperature detection thermistor 19 is omitted, a post-combustion timer that is started after the end of combustion is provided, and a preset time S (for example, S = 90 minutes) elapses after the end of combustion, that is, the end of combustion between the rear set time S (S = 90 min), by raising by changing the antifreeze set temperature t _s to a high value t _s1, when the heating temperature thermistor 15 is heated by the heating operation, the heating temperature It is known that the antifreezing operation can be started even if it takes time to cool the thermistor 15.
[0005]
[Problems to be solved by the invention]
However, the conventional anti-freezing device for a hot water heater has the following problems.
Because an ambient temperature detection thermistor is required, it is difficult to prevent an increase in cost. If the ambient temperature detection thermistor is removed, the heating temperature thermistor is difficult to cool after the heating operation is completed, and the antifreezing operation is not performed. There was a problem that the temperature would freeze.
Further, as shown in FIG. 5, during the post-completion combustion S (S = 90 min), when raised by changing the antifreeze set temperature t _s to a high value t _s1, freeze prevention operation in addition to normal heating operation The anti-freezing operation is repeated after the combustion, and there is a problem that the anti-freezing operation may be shifted even when the anti-freezing operation is unnecessary.
[0006]
An object of the present invention is to simplify the configuration by eliminating the need for an ambient temperature detection thermistor, and to prevent unnecessary freeze prevention operation even if the freeze prevention temperature is changed to a high value to increase the freezing prevention temperature. Is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a freeze prevention device for a hot water heater according to the present invention includes a hot water heater, and is provided in a heating forward line connected to a hot water outlet side of the hot water heater in a hot water heater that circulates hot water. , A heating temperature thermistor that starts anti-freezing operation when it detects that it has fallen to the anti-freezing temperature, and a post-combustion timer that starts at the end of the combustion operation. By adopting a high anti-freezing temperature that is raised, before the set time elapses after the end of the combustion operation, the heating temperature thermistor is used after the end of the combustion operation by adopting the start temperature of the anti-freezing operation, that is, the raised anti-freezing temperature. Even when the cooling of 15 takes time, the freeze prevention operation can be quickly started.
In addition, by adopting a freeze prevention temperature obtained by raising the freeze prevention temperature, it becomes easy to shift to the freeze prevention operation, so that the set time can be shortened.
Further, by starting the post-combustion timer only at the end of the heating operation, there is no possibility of starting an unnecessary freeze prevention operation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 3, a schematic configuration of a hot water heater to which the present invention is applied will be described. It has a water heater 1, a heating forward line 3 is connected to the outlet side of the heat exchanger 2 of the water heater 1, and a heating return line 4 is connected to the inlet side of the heat exchanger 2. Drain plugs 31 and 41 are provided at the end of 4.
The heating return pipe 4 is provided with a circulation pump 5 and an expansion tank 7, and a drain pipe 6 having a drain plug 61 is branched. The expansion tank 7 includes a water refill pipe 71, an overflow pipe 72, and a water level detection. And an electrode 73.
A gas conduit 81 is connected to the combustor 8 having the ignition electrode 9 and the flame detection electrode 10. The gas conduit 81 is provided with a gas governor 12 and a gas electromagnetic valve 13. An electrode 10 is provided.
[0009]
A control device 14 such as a computer is provided, and is provided in a heating temperature thermistor (high temperature thermistor) 15 and an airing safety device 16 provided in the heating forward pipe 3 and a combustion fan 11 communicated with the lower part of the water heater 1. The rotation speed sensor 17 and the overheat prevention device 18 provided in the vicinity of the casing of the water heater 1 are connected to the control device 14.
Although not shown, a post-combustion timer that starts at the end of the combustion operation is provided, the set time S after the end of the combustion operation is measured, and as shown in FIG. By not starting at the end of the freeze prevention operation, unnecessary freeze prevention operation can be prevented.
[0010]
The operation will be described with reference to the flowchart of FIG. 1. When it is determined that a set time S (for example, S = 90 minutes) has elapsed since the end of the previous combustion operation, and the set time S (S = 90 minutes) has elapsed. When the normal operation is performed and the detected temperature T of the heating temperature thermistor 15 is equal to or lower than a predetermined freezing prevention temperature to (for example, to = 7 ° C.), the circulation pump 5 is turned on to start the freezing prevention operation. It is confirmed that the detected temperature T of the temperature thermistor 15 is equal to or higher than a preset anti-freezing set temperature t _s (for example, t _s = 19 ° C.), and the combustion is stopped by turning off the combustor 8 while circulating. When a transition is made to the post-pump operation in which the operation of the pump 5 is continued and a predetermined time s (for example, s = 5 minutes) has elapsed, the operation of the circulation pump 5 is stopped and the freeze prevention operation is terminated.
[0011]
Further, before the set time S (S = 90 minutes) has elapsed since the end of the previous heating operation, the freezing prevention temperature to is increased by a predetermined value, and the detected temperature T of the heating temperature thermistor 15 is higher than that in a normal case. When the temperature becomes equal to or lower than the raised freeze prevention temperature to ₁ (to ₁ = 19 ° C.), the circulation pump 5 is turned on and the freeze prevention operation is started, and the detection temperature T of the heating temperature thermistor 15 is set in advance. After confirming that _ts (t _s = 19 ° C.) or more is reached, the combustor 8 is turned off to stop the combustion, and the operation shifts to the post-pump operation in which the operation of the circulation pump 5 is continued. When s = 5 minutes), the operation of the circulation pump 5 is stopped and the freeze prevention operation is terminated.
[0012]
According to this configuration, before the set time S (S = 90 minutes) elapses after the combustion operation is finished, the start temperature of the freeze prevention operation, that is, the raised freeze prevention temperature to ₁ (to ₁ = 19 ° C.) is adopted. Thus, even when it takes time to cool the heating temperature thermistor 15 after completion of the combustion operation, the freeze prevention operation is started promptly.
Further, by adopting the anti-freezing temperature to ₁ obtained by raising the anti-freezing temperature to ₁ , it becomes easy to shift to the anti-freezing operation, so the set time S can be shortened.
Furthermore, since the post-combustion timer is started only at the end of the heating operation and is not started in the combustion for preventing freezing, there is no possibility of starting unnecessary anti-freezing operation.
[0013]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
In a hot water heater that has a water heater and circulates hot water, a heating temperature that is provided in a heating forward pipe connected to the outlet side of the hot water heater and starts a freeze prevention operation when it is detected that the temperature has fallen to a freeze prevention temperature It is equipped with a thermistor and a post-combustion timer that starts at the end of the combustion operation. By adopting the start temperature of the freeze prevention operation, that is, the raised freeze prevention temperature before the passage of time, the freeze prevention operation can be started promptly even if it takes time to cool the heating temperature thermistor 15 after the completion of the combustion operation.
In addition, by adopting a freeze prevention temperature obtained by raising the freeze prevention temperature, it becomes easy to shift to the freeze prevention operation, so that the set time can be shortened.
Further, by starting the post-combustion timer only at the end of the heating operation, there is no possibility of starting an unnecessary freeze prevention operation.
[Brief description of the drawings]
FIG. 1 is a flowchart of a freeze prevention operation according to the present invention.
FIG. 2 is a time chart showing the operation of a post-combustion timer according to the present invention.
FIG. 3 is a schematic configuration diagram of a hot water heating apparatus to which the present invention is applied.
FIG. 4 is a flowchart of a conventional freeze prevention operation.
FIG. 5 is a time chart showing the operation of a conventional post-combustion timer.
FIG. 6 is a schematic configuration diagram of a conventional hot water heater.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Water heater, 2 Heat exchanger, 3 Heating outgoing line, 4 Heating return line 5 Circulation pump, 6 Drain pipe, 7 Expansion tank, 8 Combustor 11 Combustion fan, 14 Control apparatus, 15 Heating temperature thermistor 16 Empty Fired safety device, 17 Rotational speed sensor, 18 Overheat prevention device

Claims (2)

In a hot water heater that has a water heater and circulates hot water, a heating temperature that is provided in a heating forward pipe connected to the outlet side of the hot water heater and starts a freeze prevention operation when it is detected that the temperature has fallen to a freeze prevention temperature Freezing of the hot water heater is provided with a thermistor and a post-combustion timer that starts at the end of the combustion operation, and before the set time elapses after the combustion operation ends, a high anti-freezing temperature that is a raised anti-freezing temperature is adopted. Prevention device. The freezing prevention device for a hot water heater according to claim 1, wherein a timer after combustion is started only at the end of the heating operation.

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