Flow control and improved heat rise control device for water heaters
Disclosed are systems and devices for controlling the amount of water passing through a heat exchanger and the amount of water that by-passes the heater without passing through the heat exchanger. In some embodiments, the system includes a by-pass valve assembly having means for sensing a time-varying characteristic of fluid adjacent the inlet, means for sensing a time-varying characteristic of fluid adjacent the outlet, and a valve that alters the amount of fluid by-passing the fluid heater in response to differences in the time-varying characteristic of fluid adjacent the inlet and fluid adjacent the outlet.
1. A by-pass valve assembly for a fluid heater having an inlet and an outlet, comprising:
a. means for sensing a time-varying characteristic of fluid adjacent the inlet;
b. means for sensing a time-varying characteristic of fluid adjacent the outlet; and
c. a valve responsive to differences in the time-varying characteristic of fluid adjacent the inlet and fluid adjacent the outlet so as to alter an amount of fluid by-passing the fluid heater.
2. A by-pass valve assembly according to claim 1 in which the time-varying characteristic is temperature.
3. A by-pass valve assembly according to claim 2 in which the valve comprises a rotatable fluid diverter.
4. A gas-fired swimming pool water heater comprising:
a. a heat exchanger comprising a plurality of heater tubes or coils;
b. a manifold in fluid communication with the heat exchanger and comprising a water inlet and a water outlet; and
c. a valve assembly comprising:
i. means for sensing a time-varying characteristic of water adjacent the inlet;
ii. means for sensing a time-varying characteristic of water adjacent the outlet; and
iii. a valve responsive to differences in the time-varying characteristic of water adjacent the inlet and water adjacent the outlet so as to alter an amount of water by-passing the heat exchanger.
5. A gas-fired swimming pool water heater according to claim 4 further comprising means for altering an amount of heat transferred to water entering the heat exchanger.
6. A gas-fired swimming pool water heater according to claim 4 further comprising at least one baffle directing water flow into at least one tube or coil.
7. A gas-fired swimming pool water heater according to claim 4 in which the valve comprises a rotatable fluid diverter.
8. A gas-fired swimming pool water heater according to claim 4 in which the valve is positioned closer to the water inlet than to the water outlet.
9. A by-pass valve assembly for a fluid heater comprising:
a first sensor configured to sense a first time-varying characteristic of fluid adjacent an inlet;
a second sensor configured to sense a second time-varying characteristic of fluid adjacent an outlet;
a valve that alters an amount of fluid by-passing the fluid heater based on a differential between the first time-varying characteristic and the second time-varying characteristic.
10. The by-pass valve assembly of claim 9 , wherein:
the first and second sensors are temperature sensors; and
first time-varying characteristic is a first temperature and the second time-varying characteristic is a second temperature.
11. The by-pass valve assembly of claim 9 , wherein the fluid heater is a swimming pool fluid heater.
12. The by-pass valve assembly of claim 9 , further comprising a firing mechanism configured to alter an amount of heat generated by the fluid heater based on the amount of fluid by-passing the fluid heater.