Water heater circulation control

[yelkenli]

I have a circulation pump for my hot water supply, and I have it on a timer.  Instead, I would like to have a button in each bathroom that will turn on the circulation pump for 3 to 5 minutes.

Does anyone know of any water heater circulation pump controls already on the market, compatible with C4? 

 

[jragan]

I have a circulation pump for my hot water supply, and I have it on a timer.  Instead, I would like to have a button in each bathroom that will turn on the circulation pump for 3 to 5 minutes.
Does anyone know of any water heater circulation pump controls already on the market, compatible with C4? 
 

Why not just throw a C4 outlet switch on it and remove the timer?
https://www.control4.com/solutions/products/outlets

[Pounce]

55 minutes ago, yelkenli said:

I have a circulation pump for my hot water supply, and I have it on a timer.  Instead, I would like to have a button in each bathroom that will turn on the circulation pump for 3 to 5 minutes.

If you have to turn on the pump isn't that a bit like turning on the faucet? In fact turning on the faucet will bring hot water faster than the pump will if the system does not have dedicated returns.

A suggestion might be to installed the outlet switch mentioned by jragan and then use motion sensors to turn the pump on. Maybe timers and some advanced logic like motion in bedroom turns the pump on only in the morning hours where you expect to be headed for the bathrooms. That way you get hot water to the faucets about the same time you are needing to use the basins...

Are you worried about energy loss if you run the pump too much or is it noisy?

[jragan]

If you have to turn on the pump isn't that a bit like turning on the faucet? In fact turning on the faucet will bring hot water faster than the pump will if the system does not have dedicated returns.
A suggestion might be to installed the outlet switch mentioned by jragan and then use motion sensors to turn the pump on. Maybe timers and some advanced logic like motion in bedroom turns the pump on only in the morning hours where you expect to be headed for the bathrooms. That way you get hot water to the faucets about the same time you are needing to use the basins...
Are you worried about energy loss if you run the pump too much or is it noisy?

Th core benefit is near-instant hot water to every faucet. A properly designed and insulated recirculating on system can also double or triple the amount of hot water available because the plumbing acts as a holder of the hot water. Unfortunately most systems are not designed well combined with home owners not liking the added cost of the electricity to run the system. So they opt to add timers so the system is only recirculating when the homeowner might actually need hot water. It’s not noisy. Controlling with a switch completely defeats the system (especially if it’s well designed) and can lead to unintended consequences (like having less hot water available).

[blub]

Most sophisticated solution is to replace the pump with a low energy auto-pump like Grundfos Alpha 2 - uses only 1-3w idle. And when permanently circulation around 7-10w.

Otherwise just get a WeMo our other outplet plug. That works fine for me since I could not replace the pumps because they have a custom made part to it that would have cost me 1500€ just to replace two pumps totally wort only 400€ - so I chose the WeMo solution

[RAV]

Did one as mentioned, pluged into a C4 outlet or use a C4 light switch on the outlet the pump is plugged into.

We setup timers for morning and homecoming.

Then buttons to activate when needed on demand.

Also since it was a weekend home, tied into the home/away modes, selecting Home also activated pump. And away stopped the timers.

 

[Pounce]

11 hours ago, jragan said:

Th core benefit is near-instant hot water to every faucet. A properly designed and insulated recirculating on system can also double or triple the amount of hot water available because the plumbing acts as a holder of the hot water. Unfortunately most systems are not designed well combined with home owners not liking the added cost of the electricity to run the system. So they opt to add timers so the system is only recirculating when the homeowner might actually need hot water. It’s not noisy. Controlling with a switch completely defeats the system (especially if it’s well designed) and can lead to unintended consequences (like having less hot water available).

Yes, I know what it is. I have them in my homes. My main home has a gravity system with dedicated return lines as well as a pump. I find the pump is not needed. The others use a pump that has a timer built into the pump. I have found it helpful to put them on UPS so that they don't get off schedule with power outages. Would prefer using controlled switch and software logic.

The question was for the poster. Why does the poster feels they need to manually operate the pump rather than simply keeping them on schedule. The cost isn't always that great to run the system during predicted times. Obviously the poster wanted to only run the pump with human interaction which I would not find convenient at all. As mentioned the time to warm is greater with a pump (initiated by human) than simply running the faucet. e.g. if I was going to wash my hands I would need to remember to first hit the button for the pump and then wait what could be 10 minutes or more depending on the system. If I simply turned the faucet on and ran hot water the water would become hot much faster than the pump approach. The reason is that the bypass to bring hot water and run it back to the tank is more restrictive than letting the faucet flow in most cases.  I'm just very curious as to the use case where there is benefit from a human operated switch or event. I wondered if the noise was great or if they were concerned about the cost and if the cost was actually calculated or estimated. If its cost I would wager the convenience is most always worth the cost in a cold climate of if you have long runs through a slab etc.

In a nutshell I would probably recommend keeping a schedule and if you needed more control over schedule a C4 outlet/switch. I would try not to make people think about their hot water needs and force them to predict it. Some people are in and out of the bathroom in less than a minute. They want a warm hand wash.

[yelkenli]

On 5/12/2018 at 11:01 AM, RAV said:

Did one as mentioned, pluged into a C4 outlet or use a C4 light switch on the outlet the pump is plugged into.

We setup timers for morning and homecoming.

Then buttons to activate when needed on demand.

Also since it was a weekend home, tied into the home/away modes, selecting Home also activated pump. And away stopped the timers.

RAV: what buttons did you use to activate in the various rooms?

note: The system circulates water in a loop, from the tank, through the house, and back into the tank. 

Regarding the debate on what is better, here are my thoughts:

Capacity: Jragan is correct that capacity will increase.  However, I have a condensing tank heater (not tankless) of adequate size.  And effective capacity is volume of the tank + recovery rate right?  Condensing heaters have a much higher published recovery rate than regular heaters.  So more capacity is not needed. 

Energy efficiency: I do like to go higher efficiency, though not overboard. My pipes are PEX, which is the same material used in radiant flooring, and a quick search on the internet shows PEX has an R value of well under 1.  My PEX pipes are not insulated.  At some point I will insulate them, but even with that, they still present a very very significant surface area for energy loss (did I say the surface area is large?).  And I don't believe you can adequately insulate the pipes.  I see Lowes pipe insulation at R-8.  Maybe there is higher insulation, but that requires space.  I have R19 in the floors and R30 in the attic, and I know what those look like in volume.  Recall that with circulation, the water temperature might not drop perceptibly, but from a heat transfer perspective, one side of the PEX is 24/7 at the tank temperature; the other side at the wall/crawl-space/etc temperature.  Bottom line is all that surface area will transfer a lot of energy to areas that do not need heating, especially in summer. 

Hence the timer. 

The timer works well enough, but some of my rooms seem to be miles away, and when outside of the ON-times, I have to wait forever.   I plan to correct this by segregating my upstairs and downstairs on different circ systems, but that is for a later day, and can also be automated. 

Pounce: what data are you using to argue turning on the faucet is faster?  I don't know the pump or the faucet flow rates, so I will not make a statement on this.  There are appliances throughout the loop, even at the end, so the return piping is the same diameter (just more pipe, which does present resistance to flow).  Most hot water is for shower or laundry, and there would be busy time prior to pushing the button and getting in (if we remember to push it).  I also have a motion sensor in one bathroom, which could make it seamless, and I would maintain a timer (via C4) for on-time during known busy times.

Noise: the pump is a Grundfos, and is quiet.  I have a bedroom near the tank and pump. The noise is barely noticeable, so this is not the issue. 

Maybe not an issue: a builder friend of mine told me he spent $23k of a client's money replacing PEX in the walls, because they developed pin-hole leaks.  The client had a circulation system running 24/7 for many years.  Probably crap PEX, but who knows - maybe the flow contributed.  A PEX or plastics expert might be able to support or refute that hypothesis. 

 

[Pounce]

First, you might want to look into what types of valves you have. You may have one or many. If you don't have any you might want to consider some thermostatic values on the branches. That will automatically balance the system and get those branches that are miles away warm consistently. If you don't know these valves lets warm water pass until the valve is at temp (maybe 120F) then it closes. If you have them on every branch and each one is hot then no water is flowing down the return lines while you pump is running. 

Newer high quality pex is approved for recirc to 120F. If the failed system was older and the temp was over 120 then there was some risk. If you can grab the info off your pex and validate from the manufacturer you might feel more at ease. Also, check your home owners insurance and add some coverage for water damage due to pipe bursts etc.

 

 

[RAV]

RAV: what buttons did you use to activate in the various rooms?

Dedicated button on keypad dimmer in bathrooms.

[yelkenli]

Thanks.  Looking at the thread, I think adding motion sensors would be just as easy as the switch and solve the problem of remembering to turn on the pump.   I can use the motion sensors for home security as well. 

Thanks for your comments!