# Thoughts on the Grundfos Comfort System



## ECH (Jul 27, 2018)

Just wondering what your thoughts are on this system, specifically when a third line for recirc is NOT used and the under sink thermostatic valve is used instead.

We had a call back today for "no cold water", myself (apprentice), and the plumber I was with that day put in a comfort system along with a water heater and tank booster a few days ago. 

After doing some more research about these valves, they are normally open until the temp in the hot line reaches 95 degrees, and cold line is going to be similar. So where is the up-side to this setup? 

If the circ pump is on all the time, depending on where the cold supply comes into the house of course, you could be waiting a while for cold water.......

If the pump is on a timer, you will have both problems, waiting for hot when the pump is off, and waiting for cold when the pump is on........

Am I missing something, I don't see the value?


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## Debo22 (Feb 15, 2015)

I’ve installed a few them and like them. It should be minimal warm water on the cold side of the fixture with the thermostatic valve installed. 

It sounds like the thermostat valve was bad or installed incorrectly.


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## ECH (Jul 27, 2018)

Could be, I worked on strictly the water heater portion of that job, so I didn't get to see the valve go in. I work with a different plumber just about every day, so the chances of me being with that same guy at the same time he gets a call back are slim.

It sucks really, seeing what went wrong has a lot of value that I don't get to experience very often. 

I did get to go on a tankless call back today, that was put in last week, a Noritz that was throwing a code because the exchanger and outlet temp was climbing too high.
Turns out she was using such a low flow of water that the tankless couldn't burn low enough to keep the minimal amount of water at 120. At half a GPM the temp just kept climbing. The plumber had to go in the menu and change some settings. That was interesting.


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## Alan (Jun 18, 2008)

The thing I don't like about them is the warm water part of it. People don't like wasting all that cold water getting the warm water to their bathroom, but it seems like with the comfort system we are doing the exact opposite. Wasting that warm water to get the cold to the faucet.


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## ECH (Jul 27, 2018)

Alan said:


> The thing I don't like about them is the warm water part of it. People don't like wasting all that cold water getting the warm water to their bathroom, but it seems like with the comfort system we are doing the exact opposite. Wasting that warm water to get the cold to the faucet.


Exactly!


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## The Dane (Feb 19, 2015)

Alan said:


> The thing I don't like about them is the warm water part of it. People don't like wasting all that cold water getting the warm water to their bathroom, but it seems like with the comfort system we are doing the exact opposite. Wasting that warm water to get the cold to the faucet.


I have never installed that type of system. I have often though thought that exact same thing.

Sent from my BLN-L24 using Tapatalk


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## ECH (Jul 27, 2018)

I think the success of it comes down to where the water main ties into the system from the city. Meaning, if the main comes in close to the water heater (and crossover valve is at furthest fixture), then the hot water has a long way to get back to the heater, and so the cold line is now warm and it takes a long time to get actual cold (makeup water) from the main.

But if the main comes into the system close to the crossover valve, then when the faucet calls for cold, there isn't a long wait till the cold makeup water hits the faucet and the "cold" line being warm isn't much of a concern. Although then the concern is waiting for warm water at some other faucet.

Really the only way to do it and do it right is to install a third line and 2 check valves.


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## chonkie (Jul 31, 2014)

I've installed a few of these. Of course a dedicated return line is best. But without a dedicated line, and using the Grundfos system, the time it takes for the cold side to not be warm is a lot less time than if not having this system if it takes a few minutes for hot water to reach a faucet. Probably only takes like 10-15 seconds to get cold water on the ones I've installed.


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## chonkie (Jul 31, 2014)

Also to note, all of the grunfos systems I've installed had a timer on the pump. You can have it run all the time or you can set some dip switches (what they seem like to me) on the perimeter of the clock/timer for one time or numerous times that it should come on and turn off. I tell customers to set it up on timer to come on like 15 to 30 minutes before their normal intended use, then to turn off 15 minutes or so after they expect to not need hot water.


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## PlumbdogTim (Apr 9, 2018)

What are people waiting on cold water for? Just looking for a room temperature cup of water?


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## ECH (Jul 27, 2018)

PlumbdogTim said:


> What are people waiting on cold water for? Just looking for a room temperature cup of water?


I guess so, a cup of water for taking pills, room temp for brushing teeth etc.


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## Alan (Jun 18, 2008)

I'm revisiting this thread because i'm exploring this system for a guy who wanted me to abandon his hot water lines and put a 10 gallon heater under his kitchen sink and a 10 gallon heater under his bathroom sink.

I don't really think that's enough hot water at 110v to keep up with realistic hot water demands, so this pump with a valve at each end of the house would solve his problem of waiting forever and wasting hot water.


My question is : Why when this little thermal valve closes off, does the pump not burn up?


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## Plumbus (Aug 4, 2008)

Two minutes of purge to get the shower water warm enough to step into is reason enough to install a comfort system. For years I procrastinated, knowing that the roi would be a long time coming. I also knew that the next drought would make the argument moot. That drought came about 3 years ago and that's when I installed a comfort system. The down side is that you do get warm water out of the cold side which isn't a big deal usually, but while washing lettuce last night, I was reminded what a pita it can be.


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## Fatpat (Nov 1, 2015)

I have installed close to 100 and I’ve never had a complaint. Most customers say it’s the best money they’ve ever spent, so that makes me happy 😀


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