DHW Recerc Pump

Ron Schroeder

They use the cold water line as the return

RoosterBoy

hay guys i wanted to use my buderus 2107 recerc feature and was wondering should i pipe my loop in pex. i just think that pex would hold it's heat longer because it's not as conductive as copper of course i will insulate the whole loop and bring the hotwater right next to each (t) for each sink and tub so i get hotwater fast.

but do you think piping it in pex would be better then copper i want to use what will safe the most energy.

thanks

Brad White_42

I used 1/2\" PEX

for a temporary recirc line install (a get her done fast track project). Insulated it after several months when it became apparent that it was going to stay. Never had a leak nor any problem. Heat loss that I can tell is minimal especially with 3/4" Armaflex.

Flow rate is more than enough to do the job.

My $0.02,

Brad

RoosterBoy

so your saying that pex will definitely keep my recerc line hotter for longer then copper will right?

i will insulate the whole line for sure. also what kind of pex would you recommend i use
thanks
Jason

mario & luigi

Wirsbo .5 inch aquapex save time money and energy

Brad White_42

Mario and Luigi have it right

I used some spare heating pex I had kicking around. Cannot say it is the right stuff but it works. Key is not that it keeps your recirc line hot, it is the line TO the fixture that you care about.

Remember to place the thermostat near the fixture, not the return to the tank.

The objective is, when the fixture is in use the circulator stops because the line is warm to that point. When you place the thermostat near the tank at the return line you are sensing the round trip.

Dan_15

I wonder if you need a thermostat with the R2107 (I also have the same setup as Roosterboy), which has a built in recirc function? The thing is smarter than I am, I wonder if it is programmed to account for the difference in temp at the fixture versus the return.

RoosterBoy

dan it dose not use a t-stat but im sure you can wire the pump with one but if you have a 2107 then you wont need one you can program it to run the pump up to six times every hour for 3 Min's

i will keep mine at default 2 times every hour
do you have any pictures of your boiler setup if so post them id love to see it

thanks good luck
Jason

clammy

gravity first pump second

I might get bashed but i have done this a few times ,before buying a bronze or stainsteel pump how about running your re circ line to your home highest hot water line and then run it back to either the tanks recirc tap or drain install a shut off and a swing check valve with a 1/4 hole drilled through the swing flapper .As lng as your re circ connection is from say the highest hot water line and has no thermal traps and is basically a straight hortizontal line you may just get the re circ to work by gravity .I just did one off a buderus st50 tank works great and the HO was happy saved them the cost of a pump ,timer and aquastat and has no moving parts .Just remenber to drill that 1/4 hole in the swing check other wise you will have some major check valve rattling also use a globe valve so you can add some restriction to the line to get the check to close on a draw of hot water peace and good luck and i did the last one with wisbro 1/2 aqua pex clammy

Brad White_43

Gravity

I was going to suggest that too clammy, but my concern is, you cannot shut it off. Set with a timer and stat you can fix it to your schedule. But with gravity, when you are hot you are hot and it increases the DHW bill 24/7. Just a precaution.

It is however used in hotels where they expect 24/7 available instant hot water. Fair enough.

My $0.02,

Brad

AndrewV

about a month ago

I installed a laing pump under the sink in my third fl bath no return line needed. had to install an outlet under the sink but that was easy, just droped down from the overcounter one. It works well and has a timer and a thermostat so its not on 24/7 info can be found @ www.lainginc.com/act303.htm

just a happy customer

Andrew

Brad White_43

How does that work?

I mean, in order to get hot water to the fixture, you need a circuit. In order for a circulator to work you have to put the discharge somewhere. Where does it go? Curious.

Brad White_43

Once again, you got my back, Bruce!

I did see an installation like that once and thought it was in error. It made the cold water lukewarm to hot. Was it not done right? I like the simplicity if it works. I would love to do that in my Susan's house. There is a wait in the shower...

When I put such a system in my sister's house (Grundfos Comfort circulator) I did connect to the CW line at the DWH heater inlet, but installed a check valve so it would not do that. Are you suggesting that you can use the CW line and not make the CW too warm elsewhere?

Thanks, Bruce -always learning am I.

Brad

Ron Schroeder

Brad

They claim that ninetyb percent of the time what hot gets into the cold is ok by bthe customer as in washing haands etc, just when your looking for that cold glass of water is it a hinderence. The pump only come on when temp drops to 85 at the crossover manifold and shuts off at 95 I suppose if you insulate just the hot line all the better.

Brad White_43

I learned something once again Bruce

Hard as I try to stay ignorant, I took something as my own just now. I will seek to install one of these in the next week or so...

Thanks!


Brad

AndrewV

cold cold water

only seems to be delayed at the 3rd flr sink the rest of the fixtures don't seem affected.

YMMV

Andrew