| 摘要 |
PROBLEM TO BE SOLVED: To provide a latent heat recovery type hot water supply device capable of accurately detecting occurrence of abnormality such as attachment of scale to a primary heat exchanger regardless of thing that the primary heat exchanger and a secondary heat exchanger are bypass-connected or not.SOLUTION: A latent heat recovery type hot water supply device A includes: a heat transfer tube-type primary heat exchanger 1 and a secondary heat exchanger 2 for successively recovering sensible heat and latent heat from a combustion gas generated from a burner 3; and a control portion 4 capable of calculating heat exchanging efficiency &eegr; of the secondary heat exchanger 2, and water enters from the secondary heat exchanger 2. The control portion 4 compares the heat exchanging efficiency &eegr; of the secondary heat exchanger with a prescribed threshold value Th, determines whether the primary heat exchanger 1 is normal or not, and changes the threshold value Th corresponding to a water entering temperature to the secondary heat exchanger 2. |
