Review of the Grundfos Comfort System Hot Water Recirculation Pump 

All the home automation options nowadays are making life soooo much easier on us! Thanks for the tips and ideas!

@@danschaller1628 with the automation intelligence we can avoid a lot of CO2 emissions. Normally people use the toilet 🚽 half an hour before showers 🚿, I re-route the pipes with electric valves and Alexa so the toilet 🚽 is filled with the cold water standing in the hot water pipes. Once the toilet 🚽 receives hot water, the pipes are re-routed to their normal configuration. Then you have instant hot water at the shower. No pump ⚙️ needed. I read the idea from a gentleman in Australia 🇦🇺. Using Alexa to make the system more effective was my addition to his idea.

​@@danschaller1628you need just 1 mixing valve in the farthest sink

But aren’t you wasting a fortune by having your water heater constantly be warming up cold water that the pump is sending back to the water heater?

@@westfield90 Without being an expert, I would suggest that it is a small consideration since it isn’t exactly “cold” water being sent back to the water heater, it’s just colder than the valve’s minimum temp to stay closed. It would therefore take less energy to reheat than the actually cold new water from the municipal supply or a well.

@@jaw982 Does the recirculation pump increase the hot water pressure and flow ?

@@ajarivas72 not that I can tell. I have turned it on and off when the shower or sink was running and I don’t sense any flow or pressure fluctuations.

@@danschaller1628 thanks a lot for your answer.

Never really noticed an issue with it. The cold was always quick and seemingly uninterrupted by the recirc pump.

My wife and I are still happy with this recirculation system. I see your concern about having to wait 15 minutes. However, we are very comfortable with using a voice command while still laying in bed to activate the pump and after finally crawling out of bed, using the bathroom, and brushing my teeth, the timing works well to save some water. It just really annoys me to stand there for minutes with the water running down the drain waiting for the hot water. I have talked with other people with this same pump and have heard everything from they leave it running nonstop, and the example they use the standard timer and have it start well before they wake in the morning and let it run for hours. If you don't want to wait for however long yours will take to hit that "sweet spot" of time for near instant hot water, I'd use some of these other ideas instead of the voice control that I use. One last thought...not sure if it really matters but I have thoughts that running the pump for many hours, or all the time, unnecessarily wastes electricity.

@@danschaller1628 Thanks for the reply. I think our needs are generally predictable enough that we can set the timer to run the pump for a couple of hours in the morning and evening and that will cover most of out use. We'll just have to experiment. On another note, I've heard that when the hot water line is primed, the cold water line is now warm-hot, since it's been returning the hot water to the water heater, and now you have to wait for cold water to fill the line if you want any. Any comments on that phenomenon?

That’s a good question. I really don’t know the answer but don’t see the need if you place the valve at the furthest sink away from your water heater.

Don’t recall ever seeing heat traps on the old water heater. No sign of them now.

@@danschaller1628 Hmm.. thanks Dan.. Happy Christmas!

@@steven.h0629 Does the recirculation pump increase the hot water pressure and flow ?

@@ajarivas72 No, this system design only works while all outlets (faucets) are closed.

@@steven.h0629 Thank you for your kind replay. I appreciate it.

We moved out of the home over a year ago. So, I don't know if there are any new issues. We ran it multiple times a day and never had any problems with it. Our new home came with a recirculating instant hot water heater. However, if I ever live in a home presenting the same long wait time for hot water with a tank water heater, I would install another Grundfos recirc pump. I was definitely happy with our experience with it.

It does recirculate it back to the water heater through the cold water lines. Check out the official Grundfos video depicting the operation at ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Jd0IsylW4Cc.html

It was warm when operating.

NO new return line used with this pump but it does come with a valve that I installed under the sink to recirculate the water.

Do you know if i should drain water heater? Thank you for yor reply

@@josesosa1628 I’m not a plumber but I’d say no. Of course it can’t hurt to drain it to give it a cleaning if installing the pump.

I installed pump ofer the weekend the question now is should i leave it on all day or on schedule i have it on wyze plug so far thank you for your opinion

Yes there is one installed but it’s just out of view on the right area on top of the heater. You can see the pipe heading vertical to it.

We had the type UP15-10SU7P/TLC installed.

Just a regular outlet with constant power.

Watch this video and notice the diagram of the hot/cold water pipes and how it circulates. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Jd0IsylW4Cc.html

And no expansion tank ,no clearance to combustibles.

I’m currently a apprentice and I’m trying to figure out if you are able to put the pump on the hot water supply ? To me it just makes sense you need a return line and tie into the hot water tank (recruit inlet) and have the pump there ? Hope that makes sense and someone can help me out.

@@evandelzotto443 dedicated loop is the correct way, if you put a pump on the hot side the velocity of the water changes, I have seen hammering, balancing valves fail,and smells from hot contaminate the cold. Dedicated loop return can be throttled down and wont increase velocity of water leading to corrosive damage.

Master plumber

The valve came with the pump so I wasn't aware of its individual price, and never had problems with it so didn't need to buy a replacement. Always interesting to see different mods!

Looks like cpvc which is rated for hot water.

Good point and very relevant if one leaves the pump on constantly. I'm running the pump an average of 30-60 minutes each day and have seen no real spike in the use of electricity or propane (power for the pump and propane for the water heater). I changed the duration of my voice activated outlet (pump time) from 15 min to 30 minutes since it gives me a bigger window of time to make it to the shower after I activate it.

@@danschaller1628 Does the recirculation pump increase the hot water pressure and flow ?

It's just out of view on the right top area. No unions required when put together with copper pipes.