Hot Water recirculate

Requesting some help here. I have searched the forum and done countless google search's and am now at the point of confusion. Taco, Grundofs, Chilli, Lobster, Nibco etc….

My single level home with currently unfinished basement is plumbed with pex and uses two MANABLOC manifolds for distribution. One of these is located within several feet of the water heater the other is over 50' away. The manafold at the far end feeds the kitchen and a future bathroom, this is the problem area. I've looked at small on demand solutions for the kitchen sink but that does not solve the problem for the other fixtures. I've also considered a second hot water heater, either tank or tankless but don't really have a place for it. That leaves me with some sort of recirculation system. The MANABLOC does not recommend recirculating hot water through it, so I would tap into the 3/4 just before the manifold and recirculate back to the hot water heater with a dedicated line.

This is where the questions come. What is the best method? There are only two people in the house so I can't see the benefit of constant recirculation. Timer systems seem like a option, as do temperature but I am not sure if the temperature sensors work with pex. I also seen motion sensors and push button. I am not against any of these systems am interested in suggestions from any professional or home owner with experience here.

Last Note: The hot water source is a 40 gal gas direct vent heater. This will at some point be replaced with a storage tank heated by my boiler.

Thanks all for your input.
Link

You will be far better off with a dedicated line. You can put the circulator on a timer to suit your needs. You can also split the system that way it can serve both manifolds.

John

All of the engineered systems incorporate at least three components: the pump, a crossover, and a checkvalve. Most also have some sort of thermal control to prevent flow continuously which is especially important if you don't have a dedicated return line.

Most times, it is neater to install the pump by the WH, but it doesn't have to be there. Some systems have a crossover that can be installed in multiple locations to ensure you get hot water on each branch. I have a self-contained unit that sits underneath my bathroom vanity sink - pump, crossover, and control unit. When I remodeled, I installed a plug for it under the sink. This type, if you have power there and can afford to lose the space, is simple to install, and most people could do it in less than 10-minutes with only a pair of pliers or a wrench to undo the faucet lines and screw the bits in there.

jadnashua said:

All of the engineered systems incorporate at least three components: the pump, a crossover, and a checkvalve. Most also have some sort of thermal control to prevent flow continuously which is especially important if you don't have a dedicated return line.

Most times, it is neater to install the pump by the WH, but it doesn't have to be there. Some systems have a crossover that can be installed in multiple locations to ensure you get hot water on each branch. I have a self-contained unit that sits underneath my bathroom vanity sink - pump, crossover, and control unit. When I remodeled, I installed a plug for it under the sink. This type, if you have power there and can afford to lose the space, is simple to install, and most people could do it in less than 10-minutes with only a pair of pliers or a wrench to undo the faucet lines and screw the bits in there.

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To do it like that he would have to run it through the manablock, which is not recommended by the manufacture.

John

If you can put a T on the supply to the Manabloc, and run a dedicated line as a return, you'd shorten the time to get hot at that point...guess it depends on how close to the fixtures of interest that is. that would bypass continuous flow through the Manabloc, but if you ran home runs from it and it is near the WH, you will not gain much. If you did it as an on-demand type system, and not continuous, you'd still wait for hot water, but it wouldn't be going down the drain. You could use a proximity switch, a dedicated pushbutton, or maybe hook it into the light switch, so it only ran when you turn the bathroom light, for example, on.

Thanks Guys,

Putting a T in front of the manabloc and running a 1/2 return line is the way I think I'm going to go. I'll install a pump near the WH with a check valve and timer.

1. do I need an air bleeder? I see conflicting results on my searches if this is necessary.
2. can I use a aquastat with the timer? I'd like to circulate the HW during primary use hours and leave it at night, is that overkill?
3. If I use a aquastat, do they work with pex?
4. Opinions.... Taco or Grundofs? I have both in use on my heating system and both seem to be high quality.

Thanks again for the help.
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Keep in mind that the guts of the circulator must be either bronze or stainless steel (you can't use a steel or iron one in the potable water lines), so the pump can get fairly expensive. Sometimes, it ends up cheaper with a kit, rather than rolling your own. A strap-on aquastat wouldn't be good unless you had a section of say copper in there - you might find a place on the pump fittings to strap it. An imersion one is a little more involved. You could put the aquastat in the low-voltage line to the relay that turns the pump on. If you added a timer in the series loop, it would only turn the pump on when both the aquastat called for heat and the timer was on. This is all figured out in a kit.

Thanks Jim. I will go with the Grundfos UP10-16B5 /ATLC. looks like that has everything I need minus the check valve in a nice package.

You might also want to look at the Bell & Gossett (or Laing or ITT, or whatever brand it sells under these days) "Ecocirc e3" "ultracirc" model. It is very energy efficient, can be outfitted with a timer and/or thermostatic control, and has integral check valve and bleeder.