hot tap recirculation pump

[cfz2882]

once,in a mid-80s popular science magazine,i saw a small low power electric pump
meant to recirculate,through insulated pipes,hot water from the hot tap back to
the water heater so that instant hot water would be avalible at the tap regardless
of the distance to the water heater-anyone try this method? IIRC.the little pump
was made by grundfos.

 

[variflexpghpa]

They work great

especially if you have long pipe runs from your water tank to your bath or kitchen.
The kits are easy to install. The pump with built in timer installs in line with the cold supply to the water heater. You then install the bypass valve at the furthest point faucet. This valve is also easy to install. The supply lines from the existing faucet hook up to the valve, and the hot/cold from the existing shut off valves also connect to the bypass valve. Basically what happens is that the pump pushes the hot water thru the bypass valve into the cold line, which then heads back to the water tank. You have created a closed loop with the bypass valve.

The bypass valve has a thermostat in it which shuts the flow down as the hot water gets to it. I bought kits at Lowes and Costco.

 

[mattl]

Actually you really don't need the pump.  All you need to do is run a small line, 3/8 PEX is fine, from the furthest point and connect it with a back flow presenter to the drain on your water heater.  The natural convection will cause the water to circulate.  This is on my to do list as I have some long runs to various sinks in the house.  It only works with one connection, so choose the furthest point.

 

[hydralique]

Grundfos still makes recirculation pumps. Having one is a real water saver in larger homes because it eliminates having to run water down the drain for an extended period of time to get hot water.

 

[dj-gabriele]

I have that at home! LOVE IT!

My system is quite sophisticate: each of the bathrooms and kitchen has the pump switch connected to the light switch plus an additional "on" switch to turn the pump on if hot water is needed.
The pump is time operated and will run for 2 minutes once the switch is tripped, that's just enough to bring hot water to the pipes, plus if the water was used before and the pipes are still hot, it will not turn on.

This couples the advantage of instant hot water even if there is an almost 30 metres run of pipe from the combi-boiler and almost null power and heat loss for doing so. It's a very reliable system, installed in 2003 and zero maintenance since.

 

[retro-man]

I have one in my house and love it. Having a business on the 1st floor and living upstairs is quite a distance from the hot water heaters in the basement. I have a pump that takes the hot water from the farthest distance in the house and returns to the hot water tanks. It is on contantly so that the water is hot when you turn the faucet on. I have probably about a mile of plumbing in this house if not more and it keeps the water hot at all sinks and faucets. It sure beats waiting for the water to warm up and watching all that go down the drain.
Jon

 

[twintubdexter]

couldn't live without it...

When I bought my house the owner tried to explain some of the "features" including the three rows of eight switches in the kitchen, dining and living rooms and all of the lights they controlled inside and outside...like I could remember more than three or four. He turned on the kitchen faucet and said "see, the water's hot right away" and I just ignored it. Now, some years later I could not live without that recirculating pump. It's really more of a matter of convenience as opposed to not wasting water running it down the drain. Washing your hands, taking a shower...all so much easier when the water's hot immediately. Amazon carries these systems and I remember seeing one at Costco. They are very easy to install. Go get one!

 

[circlew]

My plumber installed a recirculation loop on the hot water line to the kitchen. I'm thinking the pump is a Tasco. Haven't used it yet as the kitchen isn't in yet, so no water is turned on to that part of the house. I'm sure I'll find it satisfactory.

 

[cfz2882]

recirc pump

sounds good-might have to rig up a recirculation pump to the kitchen sink or try
the thermosiphon arrangement mentioned by MattL.Hot pipes are not insulated,so
will have to insulate them before doing this...Washers are close to the waterheater
so not needed for those. I have some little brushed 12vDC pumps that should be
suitable-wouldn't use them for constant duty,but for intermittant duty they should
last a long time...

 

[retro-man]

If you going to do it yourself type of project with parts and pieces you have around the house just one thing to remember is that the pump and parts used at the pump have to be made for potable water, not just anytype of pump will do.
Jon

 

[volvoguy87]

A mixed blessing.

Having instant hot water is a great thing. There is, however, a downside. The standby losses with a pump system become a factor! With a normal water heater, the hot water is in the insulated tank. With a recirculating system, there is hot water in the tank AND all the pipes. All of a sudden the surface area through which water can loose its heat has been significantly increased (read, you will have to run the water heater's elements or burner more). If you install one of these, it's well worth the money to insulate the water pipes (It's worth the effort to insulate them regardless).

Insulate those pipes and save money!
Dave

 

[cfz2882]

yep,pretty important to insulate recirculated hot lines to avoid heat loss when
the recirc pump is on!
The little DC pumps i might use are about the same as the little heater circulation
pump found on some mercedes benz cars such as '83 300D.If i decide not to use these
i have a few magnetic coupled small pumps with shaded pole,phono/fartfan type moto
-one by "little giant"a couple others by gorman rupp.