Comparing the Metlund and Chilipepper Demand System Pumps – Two Water Conservation Products
A Look At The Metlund D’mand © S-50T demand hot water Pump
This article compares the Metlund D’Mand system pump, the S-50T model, to the Chilipepper CP6000. The information is predominately from the Metlund web site, but since the author, William Lund, is the original inventor of the MetLund pump, and the inventor of the Chilipepper pump, he is well qualified to evaluate the two systems.
Lets start with what a demand hot water system is and how it works. A demand hot water pumping system pumps the hot water from your water heater to your fixture, sending the cooled off hot water already in the hot water piping back to the inlet of the water heater. When hot water reaches the pump a temperature sensor detects the increase in temperature and shuts off the pump.
You now have hot water at the fixture and you did not run any water down the drain. If the pump is powerful enough you can get your hot water faster than normal as well.
Metlund S-50T D’mand Pump
Metlund has three models, the S 50T, the S 70T, and the S 02T. The S-50T is the smallest of the three models, and uses a TACO, Inc. model 006 hot water circulating pump.
Metlund lists the “performance” as “Gallons/Minute = 8” and “Total Head = 10 ft.”
This is a bit miss-leading.
Here are the pump curves from Taco’s website.
As you can see from the curve labeled 006 the pump pumps “almost” 10 gallons per minute with no backpressure at all. “0 feet of head”.
With a head of about 8 feet the flow stops completely.
Pushing 3-1/2 gallons per minute through 100 feet of 1/2″ Type L copper tubing, (which would require the fixture to be less than 50 feet from the water heater), would require over 10 feet of head.
Since the 006 cannot develop that much pressure, it probably can’t even push 3 gpm through the pipe.
From Takagi’s website, the pressure drop through a model T-K3 tankless water heater at only 2.5 gallons per minute creates a head loss of 5 feet.
If you have a tankless water heater that supplies a fixture 50 feet away, it’s unlikely that the Metlund model S-05T would even achieve a flow rate of 2 gallons per minute.
The Metlund S-50T-PF Kit ($356.00) Comes with two 1/2″” threaded male adapters two brass “T” compression fittings, two stainless steel flex-lines, and one hard-wired button.
The pump must be plumbed to the water main side of the shut-off valves under the sink due to the low head capabilities of the pump, and the high head loss through the shut-off valves.
The pump shuts off when it senses an increase in temperature of 3 degrees .
The Metlund S-50T-PF-R Kit ($411.55) is the same as S-50T-PF plus one remote control package.
The S 50 T has a 3 year warranty. It’s 1/40 of a horsepower motor is whisper quiet. You won’t even know when to turn on the hot water faucet.
The Chilipepper Model CP6000 Demand Hot Water Pump
The Chilipepper CP6000 is also a hot water demand system, and does exactly the same thing as the S-50T. The Chilipepper was designed to be hooked up with hoses, and thus needs a much more powerful motor to overcome the head loss produced by the very small holes through typical faucet connections.
A side benefit of the powerful motor is that the Chilipepper produces a flow of about 3 gallons per minute with just about any plumbing system. The Chilipepper pump has a cut-off head of 115 feet. With a 3 gallon per minute flow the Chilipepper has more than enough power to overcome the head losses in any tankless water heater and hundreds of feet of pipe.
The CP6000 has an adjustable temperature increase for shut-off. It’s adjustable from an increase of from 3 degrees to 12 degrees via a knob on the front of the case.
Connection to the plumbing is done with the same type of supply hoses as most of today’s homes. The water supply to the house does not need to be turned off. Just turn off the supply valves to the fixtures and connect up the pump.
The high rpm 1/3 horsepower motor does make noise, and you can hear it. That’s a plus since you can hear the pump shut off and you know it’s time to turn on the faucet.