FROST PREVENTION METHOD AND FROST PREVENTION APPARATUS FOR HOT WATER SUPPLYING AND HEATING APPARATUS

摘要

PROBLEM TO BE SOLVED: To effectively and surely implement frost preventing operation with a simple construction by detecting atmospheric temperature varying with operation of a hot water producing means and effecting an on/off control of the hot water producing means and a circulating pump to run a frost prevention operation. ;SOLUTION: When outdoor temperature detected by an atmospheric temperature detecting means 27 in a vicinity of a heating heat exchanger 3 and an inlet opening 9 becomes a critical freezing temperature, i.e., 3°C or lower, a circulating pump is activated and a heating burner 3a is started to burn and the heat exchanger 3 is operated. The heating burner 3a is kept effecting a weak burning so as to keep hot water at a temperature just sufficient to avoid freezing. Hot water is produced and is circulated to a high temperature side terminal heating circuit 18, a low temperature side terminal heating circuit 20 and the like. By combustion heat generated in the heat exchanger 3 temperature in atmosphere in the vicinity of the heat exchanger 3 is raised. After frost prevention operation is stopped, the temperature in the atmosphere falls down again and reaches the critical freezing temperature of 3°C or lower, and then the circulating pump 22 and the heating heat exchanger 3 are operated.;COPYRIGHT: (C)1997,JPO