Patent ID: 7628123

Claim:
A combined hot water supply system in which plural water heaters are connected in parallel to a connection controller and the water heaters are operated in association with one another, wherein the connection controller increases the number of water heaters in operation when a predetermined condition for increasing a number of water heaters in operation is satisfied, and each of the water heaters includes: a heat exchanger that heats water supplied from a water supply pipe and taps hot water to a hot water supply pipe; a burner that heats the heat exchanger; a combustion-amount adjusting means for adjusting a combustion amount of the burner; a water-supply-quantity detecting means for detecting a flow rate of the water supplied from the water supply pipe; a water-supply-quantity adjusting means for adjusting the flow rate of the water supplied from the water supply pipe; a hot-water-supply-temperature detecting means for detecting temperature of the hot water tapped to the hot water supply pipe; a hot-water-supply control means for controlling, when a flow rate of water equal to or larger than a predetermined ignition water quantity is detected by the water-supply-quantity detecting means, the combustion amount of the burner with the combustion-amount adjusting means such that hot water of a target temperature is tapped to the hot water supply pipe; and a water-supply controlling means for limiting, when operation is started according to an instruction for increasing the number of water heaters in operation from the connection controller, the flow rate of the water supplied from the water supply pipe to be equal to or smaller than a water quantity at operation start, which is equal to or larger than the ignition water quantity and smaller than a maximum flow rate adjustable by the water-supply-quantity adjusting means, with the water-supply-quantity adjusting means from the start of the operation until a detected temperature of the hot-water-supply-temperature detecting means rises to be within a predetermined temperature range set near the target temperature.