@grundfos I'm considering the use of a hot water recirculating pump. You've described it could be used, with a check valve, in an existing home and the cold-water line would return water back to the water heater. What happens if you want to use your cold water, are you then pushing all the hot water out to get cold water? And, how does this work with normal water uses like dishwasher, clothes washer, toilets, et al? Thank you.
Hey there! The Grundfos Comfort System (UP 15-10 SU7P/TLC) uses a bypass valve under the farthest sink to create a hot water loop in homes without a dedicated return line. This may briefly cause some warm water in the cold water side, but it quickly returns to cold water. No need to worry about losing hot water. For homes with multiple hot water branches, additional bypass valves may be needed for instant hot water at every tap. Using hot water recirculation benefits appliances by providing instant hot water when needed. Toilets, connected to the cold water line, are not affected. Hope that helps! -Ty
Looking online at recirculating pumps, I get the impression that the version shown in this video has been replaced with a built in timer version, is that correct? Other than the timer, is there any differences between the two?
Hey there! The current version does utilize a manual timer, and you can find more details about it here: gfos.ly/6053Xig9J Outside of the timer change, there should not be any differences between the two pumps. Hope that helps! -Ty
So this routes the water from the hot line into the cold line which will end up in the hot water tank. And the check valve shuts off when the water heats to a certain point. That means the cold water line will have hot water in it? How hot does that back flow get?
Hello Brian, the comfort valve has a small amount of cross flow at the fixture it is installed in. The tepid water is in the cold water riser, and it flushes out as soon as the cold tap is opened. No other fixtures should experience warm water in the cold line. The valve closes at approximately 95 degrees. As the water cools the valve slowly opens and a small amount of water will push through until the thermostatic element inside the valve reaches 95 again and closes. Hope that answers your question!
Hello. I am having a heck of a time finding a recirc pump for a tankless water heater for 4 bathroom home for a medium to medium-large home (4000 sq ft including basement). Can you please help?
Hey there! The circulator will increase the flow slightly to push the water to the valve and then back to the water heater. Depending on the size of the pump this will be different. Example: a 15-29 will be less than a 15-55. For the Comfort System, which is for homes without a return line - this pump is very small (15-10). The new ALPHA CS is larger but has technology built-in to make sure it doesn't produce flow that is over the pipe guidelines to help reduce the risk of pin holes. Hope that answers your question! -Ty
If my grundfos is really hot to the touch, can I assume it is faulty? We had a frozen line that broke, and I had to shut off water supply at the main. I believe that during the shutdown, the circulator continued to run thus somehow burning itself to lock up?? How do you tell if it is circulating at normal expected capacity?
Hey there! It's hard to say for certain without having a bit more info. If you would like to e-mail me at namregsocial@grundfos.com with your pump model, preferred contact info, and location, that would help greatly in providing support. Thank you! -Ty
I have one of these systems installed. I am finding that the cold line water is always warm/tepid - even after running the cold for some time. How can I test the check value is operating correctly?
Hey there, The presence of warm water on the cold side is a side effect of this system. If the valve remains open, the water can become very warm or even hot. You can test this by turning off the cold water shut-off valve located under the sink and then opening the faucet to full cold. Water from the hot side will cross over through the valve. When the valve reaches a certain temperature, it should close, and the faucet will no longer run water. However, if the valve is stuck open, the water will continue flowing. The simplest way to prevent warm water on the cold side with a correctly functioning valve is to use the pump's built-in timer. Set it to run for 15 minutes, and then turn it off for another 15 minutes. This should help maintain the desired water temperature and prevent the warm water issue. Hope that helps! -Ty
so this is pushing water from the hot water line backwards into the cold water line. that doesn't make sense. You're likely to overpressure the line and blow it out. Also, how does the pump know there is cold water in the hot water line? There's no sensor at the cross over valve.
Hey there! The hot water tank is fed by the same cold water system, and the cold water supply line acts as a recirculation line back to the tank. Consequently, the tank, hot water supply, and cold water supply tank all form a large loop. The crossover valve incorporates a thermally actuated piston. This feature enables the valve to remain open for crossover flow from hot to cold when the pump is operational and the water is cold. The thermally actuated piston is fully closed once the valve reaches approximately 100°F. Additionally, a check valve is installed to prevent cold water from flowing into the hot side. Hope that helps! -Ty
Hello there! That could definitely be the case. Regulations and applications vary from country to country. This specific video is meant for the US market where a return line is not required, and a water filter is an optional choice. Hope that helps! -Ty
Hello, The ALPHA Comfort System pump will turn off (go into stand by) when the valve closes. The pump will then stay off for about 15 minutes, and then run again during operating hours. Hope that helps! -Ty
Yes, the system was actually designed for continuous pump operation. When the valve closes, it does open slightly, maintaining a very low flow while the pump operates at just 25 Watts. Hope that helps! -Ty
Hey there, this would definitely be a high level DIY installation that would require a little knowledge about plumbing. However, we always recommend contacting a local licensed professional for help with installations.
Hey there! The Comfort System shown in this video does not work with a tankless water heater, however our brand new ALPHA Comfort System does. You can find more info here: gfos.ly/6059bQ1hH
Hey there! You can use the form on this page to get in touch with someone to purchase: gfos.ly/6050Ra9SQ Hope that helps, let us know if we can help any further! -Ty
