| | | | | flows. |
| | | | | For example, a flow of 3-1/2 gallons per minute |
| Comparing Green Plumbing Systems: <a | | | | through 100 feet of 1/2" type L copper tubing |
| rel="nofollow" | | | | requires a pressure of 4.3 PSI (10 Ft. Head). 100 |
| onclick="javascript:pageTracker._trackPageview(' | | | | feet of pipe would service a fixture about 40 |
| outgoing/article_exit_link');" href=" Hot Water | | | | feet from the water heater. Any elbows or |
| Systems</a> | | | | valves in the line add to the back pressure. |
| | | | | Tankless water heaters require around 8 Ft. of |
| For more information about all kinds of water | | | | Head (3-1/2 PSI) for a flow of 3-1/2 gallons per |
| heaters: <a rel="nofollow" | | | | minute. Adding the two pressure drops together |
| onclick="javascript:pageTracker._trackPageview(' | | | | yields almost 8 PSI (18 Ft. Head). |
| outgoing/article_exit_link');" href=" Heater | | | | Since that is above the cut-off pressure of the |
| Problems</a> Tankless and tank type water | | | | S-70T, it can never pump that much flow. So |
| heater information. | | | | take what the Metlund web site says with a grain |
| Demand type hot water delivery systems are | | | | of salt. |
| designed to speed up the delivery of hot water | | | | If you have a tankless water heater that supplies |
| to your fixtures without running any water down | | | | a fixture 50 feet away, it's unlikely that the |
| the drain. These systems only operate when | | | | Metlund model S-05T would even achieve a flow |
| you "demand" your hot water by activating the | | | | rate of 2 gallons per minute when used with a |
| pump. Usually that means pushing a button. | | | | tankless water heater. |
| The pump is normally located under the sink from | | | | The pump must be plumbed to the water main |
| where the hot water is demanded. Depending on | | | | side of the shut-off valves under the sink due to |
| your plumbing layout one pump can service more | | | | the low head capabilities of the pump, and the |
| than one and often all of the fixtures in a home. | | | | high head loss through the shut-off valves. |
| Once activated the pump sends hot water from | | | | The Metlund pump shuts off when it senses an |
| the water heater to the fixture, hopefully more | | | | increase in temperature of 3°. |
| quickly than if you just ran the faucet full-blast. | | | | The prices listed are from Metlund's website. |
| The cooled off hot water in the hot water pipes | | | | S-70T-PF-R Kit ($518.65) |
| is sent back to the water heater inlet via the cold | | | | Same as S-70T-PF plus one remote control |
| water pipes. | | | | package. |
| When the pump senses an increase in | | | | S-70T-PF-V-102 ($542.50) |
| temperature it shuts off. That prevents hot | | | | Same as S-70T-PF plus one hard-wired motion |
| water from filling the cold water pipes. When the | | | | sensor. |
| pump shuts off you have nearly instant hot | | | | The Chilipepper Model CP6000 Demand Hot Water |
| water at the faucet, and no water was run down | | | | Pump |
| the drain. | | | | The Chilipepper was designed to be hooked up |
| The Metlund S-70T Hot Water Pump | | | | with hoses, and thus needed a much more |
| The Metlund S-70T actually uses a Taco Inc, | | | | powerful motor to overcome the head loss |
| Model 008 Cartridge Circulator pump. | | | | produced by the very small holes through typical |
| According to the Metlund web site the S-70T | | | | faucet connections. The CP6000 has a maximum |
| models are designed for homes under 3500 | | | | Head of 115 Ft (50 PSI). |
| square feet and adequate for runs of up to 100 | | | | Connection to the plumbing is done with the same |
| feet. The pump curves can be found at the | | | | type of supply hoses as most of today's |
| Taco Pump web site, and the curve marked | | | | homes. The water supply to the house does not |
| "008" is the curve for this pump. | | | | need to be turned off. You just shut off the |
| Metlund lists the "performance" as "Gallons/Minute | | | | angle stops under the sink, connect up the hoses, |
| = 14" and "Total Head = 16 ft." As can be seen | | | | and turn the valves back on. |
| from the pump graph curve #008, the 16 Ft. | | | | The powerful Chilipepper pump works great with |
| (7PSI) is the amount of back pressure needed to | | | | any tankless water heater on the market |
| stop the pump from pumping any water. | | | | regardless of brand or model. |
| The 14 gallons per minute is how much water the | | | | The high rpm 1/3 horsepower motor does make |
| pump would pump if there was no backpressure | | | | noise, and you can hear it. It's very handy to be |
| at all. The actual flow that the pump produces | | | | able to hear the pump shut off, because that |
| depends on the backpressure produced by the | | | | way you know when to turn on the faucet. |
| friction of the water against the pipe wall as it | | | | |