Hot Water Recirculating system?

Cyclist77 · October 22

In the process of installing the Weil-McClain CGa3 and the indirect DHW. Had a thought last night about including a recirculation pump so I could locate the new tank closer to the boiler and that puts it farther from the first floor master bathroom.

The o line systems I see have a sensor underneath the sink. I wo like to recirculate all the water at that end of the hose.

Any sketch you might be willing to share?

Thanks

EdTheHeaterMan · October 22

Assuming that you have a dedicated return line from the furthest hot water tap bsck to the boiler room, you can operate it constantly so there is no need for any sensor at al. That would be a waste of energy since you probably only use that hot water tap for 20 to 50 minutes per day. sp for more than 23 hours per day you would be sending hot water out to the piping system just so it can give off heat to the walls and crawl spaces where the hot water pipes are located.

I had an interesting idea when i lived in a single Ranch Home in New Jersey. Connect the recirc pump to the light switch in the bathroom. when you go in to use the facilities, the first thing you do is to turn on the light. that will also start the pump to move all the cold water from the hot water lines so by the time you are ready to wash your hands, the hot water is already there.

Don't forget to turn out the light when your are done. you will be wasting more than just the electric for the light bulb.

Cyclist77 · October 22

Ed,

As was sitting in the bathroom! I had the thought of a switch!

I ne er let time go to waste!

Cyclist77 · October 22

So after looking over the basement piping I think I have a plan. I will run a 1/2" return line to the tank and use a pump from a previous setup. It is a Taco 006-BC4.

Cyclist77 · October 22

After doing a bit more searching I came across a "non pump" or passive setup using a check valve.

Any thoughts??

Alan (California Radiant) Forbes · October 22

Thermosiphon (passive setup) is my favorite as long as you have room to slope the supply pipe upwards and the return line downwards. You want to ream the pipe to reduce turbulence and pressure drop. I would use 3/4" pipe for pressure drop reasons and a swing check, not a spring check. Insulate well.

Circulation is always on unless you add a timer and a zone valve/solenoid for potable use.

Jon_blaney · October 22

When you need hot water, turn on the bath tub, not the shower. It has no flow restriction. No cost solution.

tim smith · October 22

I used an occupancy sensor in my bathroom pointed at door which was appx 40 ft from my tank. oversized pump a bit from a 15-10 grundfos. Used 3/4 return line to speed up flow with out washing out. It would have hw at tap by the time I got ready to use hot water. just had it on short run time.

Larry Weingarten · October 22

Hi, The gold standard in my opinion is the ACT Metlund demand system. It does what @tim smith did and has remote push buttons and temp sensor to tell the pump when to turn off. It saves around 90% of thermal losses. At the other end of thngs, a well insulated gravity system can work, but some old timers taught me to drill a small hole in the swing check, as gravity might not open it.

Yours, Larry

JUGHNE · October 24

I have had the passive recir system in my house for over 10 years.

Instant hot water at the farthest fixture. I know it is a continuous heating loop, but for 6 months of the year we are is heating mode anyway.

Just a swing check (no hole drilled in flapper) at the bottom of the tank for the return line. Also a nearly closed ball valve to limit flow thru the tank.

This also tends to keep my oversized tank (120 gallons) from stagnation/stacking.

The extra energy NG cost I believe is negated by not having to buy & replace a SS or brass pump, timer, controls etc. (and KW) for the rest of the life of the house or me.

mattmia2 · October 24

Could you just put the tank where the bathrooms are and run boiler side lines from the boiler? That would be much better if you have the space in the basement.

ChrisJ · October 24

I use an aquastat on mine mounted right by the pump (Taco 006) at the end of the line.

In all seriousness, the amount of power the pump uses is so little I doubt you'd even notice it on an electric bill if it ran 24/7. Worse case, $7.00 a month to run 24/7. Wonder if I'll even recoup what I paid for the aquastat in savings, because it's not gonna cut that $7 in half.

JUGHNE · October 24

I set mine up with the intention of adding a pump if needed, however it has performed quite well.

My summer WH NG uses 23-25 CCF a month, about $35 a month.

Would I save 10% a month with the $400 investment? Don't know…..actually don't care. Old guy here……like to keep things simple.

ChrisJ · October 24

https://forum.heatinghelp.com/discussion/comment/1869107#Comment_1869107

Getting it done without a pump is always better.

For example, steam heat.

JUGHNE · October 24

We do have hot water but not quite that hot.

A friend in the trade had a recir pump for DHW. After some years he realized the pump had failed and he was getting circulation to his 2nd floor without it running.

Cyclist77 · October 24

Original poster here. My idea is a 1/2" return line and wondering about using people as a $ savings. Ok idea??

ChrisJ · October 25

https://forum.heatinghelp.com/discussion/comment/1869139#Comment_1869139

Using people?

Can you expand on that?

mattmia2 · October 25

pex?

Hot Water Recirculating system?

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