Automated Recirculating Hot Water System

[miked]

We had a Metlund system, and it worked well. However, when we remodeled our bathroom, the designer chose to have exposed piping under the sink, so it was no longer an option. We went with the Grundfos instant hot water system. It also works well.

The only downside with the Grundfos is that when you use the cold water tap in the specific sink, you sometimes have to wait 10 seconds to get cold water. Not a big deal, really.

 

[MrGibbage]

These add on systems that don't require a separate return line... I think I read somewhere that they use the cold water line??? So, does that mean when you go to use the cold water that you have to wait for it to push out all the hot water that's in the line?

 

[DavidL]

Yes, I think that would be the case, but since you proactively choose to run the circulation pump, you are choosing hot water. If you made that choice, and then wanted cold water, then you would have to wait for cold.

 

[miked]

The return line is the cold line, you're correct. This hasn't been a problem for us. At most, at the sink where the cold meets hot, you'll get maybe 10 seconds of warm (not hot) water before the cold flows. And it's never a problem anywhere else in the house.

 

[ricklearned]

I have a hot water recirc system that works great. I have a return line back to my water heater and a small pump near the water heater. The pump is activated by a relay controlled by an ocelot. The hot water is recirculated for two minutes on fifteen minute cycles during the early morning and evening. My pipes are insulated so they keep the water warm for a while. I also have a momentory switch which will trigger the ocelot to run the pump for a minute which will get me instant hot water anytime that the morning or evening cycles are not on.
I have an Elk M1 on order and am looking forward to putting this on the M1 and including a rule so it doesn't run when the system is armed. I also plan on turning off my water heater when I am away to save energy.

 

[noshali]

I have done some research on tankless water heaters and this is what I found out.

1. The install is a bit tricky as one cannot use existing exhaust for your water heater that in my case is also the chimney for my furnance. There is also an issue of how many turns the exhuast can have plus it also needs an air intake dedicated to it. I had an installer come in to give me an estimate. The water heater was for about $900 but the install was going to be $1000 as my whole house is finished including the basement (no false celing, drywall ceiling in the basement).

2. This year the federal govt. is offering $300 in tax rebate as an incentive also but I could nto justify paying $2000 for a water heater.

3. No one has really been able to answer (including the installer, which put me off) was what happens in the middle of winter and all someone wants to do is wash their hands. Maybe you guys can shed some light on this. pumps etc make sense but it just seems too much just to get hot water.

regards,

 

[Steve]

I was getting ready to try a recirculating system and found this one. It seems to overcome all of the issues with all these other systems (noise, too much hot in the cold line, etc). Has anyone used one of these Redytemp units?

 

[Ranger Digital]

nosh, its no different than when someone wants to wash their hand with a tanked heater. Turn water on, warm water tanks a while to get to faucet. the tanked version COULD be set to push out HOTTER water though. Course that cost more money and is not efficient.
edit: oops, way old thread.

 

[beelzerob]

Demerits to Steve for resurrecting a 2 year old thread...and then tricking poor Ranger into replying to it.

 

[Ranger Digital]

beez, LOL. I still had the thread on my screen and noticed how old it was. Edited it, posted it and now saw your post, LOL.

And you are right! He got me, lol.

 

[Steve]

Hey, I asked a simple question and did not hold a gun to anyones head to go back and reply to previous questions Figured was better than starting a new thread - and yes, I've done that before myself, so Ranger - don't feel bad...

So, the current question on this old table is... "Is anyone using a RedyTemp unit"? Hard to find any info on it and I've searched like crazy.

 

[SethP]

I have a built-in recirculator. It has a separate pipe running back from the kitchen to the hot water heater. It works very well - BUT:

I'm using a current transformer connected to a 1-wire input to log all activity of my furnaces. With the recirculator off, the heater runs every 4 hours to keep the tank hot. With the recirculator on, it runs every 2 hours. Twice as much standby energy used. This is with fully insulated pipes and maybe a 50 or 60 foot run from the water heater.

Therefore, a timer is crucial to keep energy usage in check.

Mine was hardwired, so I cut the wire, put in an outlet, and ran it through an appliance module. I'm going to install hardwired pushbuttons in the bathroom and kitchen shortly to request hot water, and play with a motion sensor as well, so if there's motion in the morning between 7 and 8, get hot water. It will take a bit of tweaking.

Seth

 

[khearn]

My house has a gravity hot water recirculation system. No pump required. It has a return pipe from the highest faucet in the house. All of the hot water pipes are insulated except for the last several feet of the return. So that bit cools down just a tad, becomes denser and flows back down into the heater, drawing hot water up through the pipes. The shower is hot in just a few seconds and no electricity is wasted. Plus, it's silent.

I'm not sure how well it would work in a one-story house though, ours is 2 story.

Keith

 

[hucker]

My house has a gravity hot water recirculation system. No pump required. It has a return pipe from the highest faucet in the house. All of the hot water pipes are insulated except for the last several feet of the return. So that bit cools down just a tad, becomes denser and flows back down into the heater, drawing hot water up through the pipes. The shower is hot in just a few seconds and no electricity is wasted. Plus, it's silent.

I'm not sure how well it would work in a one-story house though, ours is 2 story.

Keith

Keith:

There is no free lunch. You might not use any electricity or a pump but the uninsulated pipe is what is driving the system and that is a heat loss that requires extra power. It is far more elegant that is for sure!

 

[nsisman]

My house has a gravity hot water recirculation system. No pump required. It has a return pipe from the highest faucet in the house. All of the hot water pipes are insulated except for the last several feet of the return. So that bit cools down just a tad, becomes denser and flows back down into the heater, drawing hot water up through the pipes. The shower is hot in just a few seconds and no electricity is wasted. Plus, it's silent.

I'm not sure how well it would work in a one-story house though, ours is 2 story.

Keith

How does that work when the hot water lines are pressurized ?

I can't visualize any water being returned in a closed system without a pump to cause circulation ?