Automated Recirculating Hot Water System

[Steve]

Mr. RedyTemp

It's good to see a manufacturer reply. I was wondering how you found this site and thread? Anyway, I have a few questions if you don't mind.

1. Besides the variable vs fixed temperature sensing, what are the difference between your product and Metlund? Why would I want to choose RedyTemp?

2. On the subject of temp sensing, Metlund claims that they use the 6-8 degrees above ambient because then 115 degree water is only a foot or two behind and this insures that hot water does not get into the cold line. While I understand your adjustability, isn't is possible alot more hot water can get into the cold line if adjusted too high? Maybe I am missing something but if Metlunds claims are accurate then the fixed sensor should work in all situations, no?

3. Metlund appears to have several dealers where you appear to sell direct only. Is that true?

4. What is the real difference between the ATC-3000 and TL-4000 when used on a standard tank heater? Which would you recommend and why? Why would one spend an additional $175 minimum on a TL?

5. What department at RedyTemp do you work in and are you available if one were to call in?

Thanks again for your participation here!

 

[dougmeredith]

I've been thinking about this for a while and am considering rolling my own. My plan would be to put a circulating pump and check valve in my mechanical room on the hot water line. I might also plumb a straight pipe in parallel to the pump, just to be sure that there is no restriction to the water flow. This pump would be controlled by my home automation system. At three or four locations in the house, I would have a valve (also controlled by the HA system) that would allow hot water to cross over into the cold. There would be a temperature sensor on the hot water line at each of these points.

The HA system would turn on the pump whenever at least one valve was open. Rules could include hot water temperature, time, motion in the bathroom, and bathroom door closed. The beauty of rolling my own is that I can tweak these rules over time to get exactly what I want.

I'm not sure I can do this as cheaply as a commercial system, but I think I can do it better.

Doug

 

[amirm]

FYI, these things can damage your pipes if they get air in them. Ours did, and proceeded to create a pin hole in our copper pipe which took some time to figure out.

I've never seen this said before. How would this system introduce air into your pipes? Why would the air cause a hole in a copper pipe?

It doesn't introduce it itself. But should you get air into your pipes (e.g. water being shut off by the city, etc.), then some of it gets trapped in the pump. You will hear the noise. At least a while until the impeller self destructs as it did in ours.

Of note, there is a way to mount them as to avoid this. There is a height requirement which needs to be followed and ours was not done that way. Nor did it have shut off valve to easily replace the impeller.

In our second house, we are putting two hot water tanks instead of a single larger one. We had this before and it eliminates the need for the above pumps which can waste a lot of energy as they recirculate the hot water in the uninsulated pipes in your house.

How do the two tanks eliminate the need for the hot water recirculation system? Is it because you put the tanks in different locations so that they are closer to where the hot water is needed?

Doug

Yes. We put one near the kitchen and another near the bedrooms/shower (the two are the extremes of the house). Each then gets hot water very quickly. That system is superior to our primary house which has a pump. As noted by someone else, the pumps have timers so they only work part of the time (running them all the time wastes even more energy through the pipes). And mix hot and cold altough that is not a consideration for us....

 

[gbirk]

I’ve been considering this for a while. My plan would be to put a dedicated re-circulating line with a check valve and pump installed on the return line. I’ve been considering the Metlund S-70T. I have an ISY. Can I just get buy a re-circulating pump like the Taco Model 008 and have the ISY control the pump? I could set rules to have the ISY turn the pump on based on time, motion in the bathroom, a light or fan turned on in the bathroom, etc.

Thanks for your feedback.

 

[apostolakisl]

Costco sells one made by Watts. Anybody used this one? It looks easy to install,. is relatively cheap, and could be run off of an insteon appliance linc allowing you to actviate it via motion or perhaps an insteon light switch in the bathroom.

 

[RichardK]

In our house the kitchen is far from the hot water heater and it can take a long time to get hot water. I like the concept of a small recirculation pump under the sink, but it occurs to me that the hot water that's forced into the cold water line is also softened water (all of the hot water in the house is softened). So some of the drinking water would have sodium introduced, unless there's something in this scenario that I'm missing.

 

[Steve]

@gbirk: The Metlund unit you linked and the Taco pump are completely different approaches. The Metlund is installed at the point of use (or furthest water outlet on a line) and pulls hot water thru until the desired temp. The 'cool' water is pushed into the cold line. The Taco pump is typically installed at the water heater and pushes water thru the system and is returned in a dedicated return line.

@Lou: I believe the Watts unit is the same sold at Home Depot and is similar to the Taco pump. It goes on the water heater and has a built in timer and uses a recirculation return line.

@Richard: IMHO there will be a very negligible amount of sodium you would ingest and is nowhere near important enough to cause any issues.

 

[ano]

I have the Watts unit, and it works good. Where I live the water company reimburses the cost of the unit up to $250, I think. I had to install 4 of the diverter valves on faucets to get hot water everywhere. The amount of warm water going into the cold is quit small, and turning in the cold water for 2 seconds removes that. I'm not sure how it works in your house, but mine has soft water going to both hot and cold taps. When we wash clothes and take showers, both hot and cold water is used. If you are worried about sodium in the water, then I would switch to the salts they have that use potassium instead of sodium and/or add a reverse osmosis water filter for drinking water. That should remove 95% of any sodium in the water.

 

[apostolakisl]

Reverse Osmosis is great. I bought the one at Costco which I believe was a Watts model. My wife insisted and I was like alright whatever. But she was right, the water really is a lot better and I don't consider our city water to be bad in the first place.