Plumbing Question

Mooseherder · January 05, 2025, 01:58:29 PM

This is at my daughter's house. Anyone know what it is for? She thinks it has something to do with energy consumption, but it doesn't make any sense to me. It runs 24/7 and you can hear it on when on the other side of the wall.

WV Sawmiller · January 05, 2025, 02:08:31 PM

Why isn't it a hot water heater?

Mooseherder · January 05, 2025, 02:24:57 PM

The do hicky on the side of the water heater.

Brian_Rhoad · January 05, 2025, 02:58:16 PM

Could it be a circulator that pumps hot water through the hot side of the pipes so you have instant hot water? You wouldn't need to run cold water out of the pipe to get the hot water.

Google "Grundfos hot water circulator"

Old Greenhorn · January 05, 2025, 03:34:44 PM

OK, this is a shot in the dark but hear me out. (Then you can laugh.)
This is a valve with a timer that is coming off the bottom of the heater, also call 'the drain'. Depending on the type of water you have, these water heaters tend to collect sludge in the bottom over time which restricts water flow. It is a very simple thing to just drain the bottom junk off the heater from time to time. My parents house had/has this issue. I would just drain off the bottom 5 gallons and all was good for several weeks or months.

What you have here seems to be an automated drain that will go 'open' for a short period every few weeks or months and drain that junk off. I'll bet the other end of that pipe is either in a drain or to the outside. What is the timer set to? how often and for how long does it 'open'?

It's actually a good idea that should add to the lie of the water heater.

Menagerie-Manor · January 05, 2025, 03:47:48 PM

In the trade it would be known as a recirc pump to maintain the domestic hot water piping up to temp on installations with long runs to the furthest fixture. It's a nice feature having almost instant HW but these days with energy costs being what the are ...

Most systems include an aquastat downstream with a setpoint and range so it's not running 24/7, not familiar with the timer arrangement...

barbender · January 05, 2025, 04:20:36 PM

Yep, recirculation hot water loop.

beenthere · January 05, 2025, 04:25:15 PM

I believe OGH nailed it, seeing that it is an electric hot water heater.

Where does the copper pipe go after it exits through the wall? Known or not? Suspect it goes to a drain, but pump shouldn't be running 24/7.

Ljohnsaw · January 05, 2025, 04:27:41 PM

Probably a recirculating pump. The timer just needs to be set properly if it still works. You'd set it to run just before you get up in the morning to take your shower and maybe again to run before you do dishes so the hot water is there.

A guy I do odd jobs for had a BIG tankless installed to save on his propane usage. Then he had a recirculating pump installed that ran 24/7/365 🤔🙄

Mooseherder · January 05, 2025, 04:31:27 PM

I don't see where the pipe is going because it's in the wall. Here is a 20 second video of it in action.
I'll do some more research after dinner.

https://youtube.com/shorts/g6-P2A8OJrM?si=WjEHybO4GtZnySHe

beenthere · January 05, 2025, 04:47:06 PM

Not seeing where any of the timer tabs are set up for any off-time period. If it is pumping off hot water 24/7 then it is far from an energy saver.

SawyerTed · January 05, 2025, 04:58:50 PM

The timer appears to be set to ON 7 am to 9 pm. The blue tabs pushed in are OFF and pushed out are ON.

Looks to me like reprogramming the timer to "at home and awake" time set to ON and "away or asleep" set to OFF is needed.

Is there a 7 day timer that could be used?

There is a timer OFF setting on that middle switch. That should turn the pump off completely

doc henderson · January 05, 2025, 05:10:17 PM

We thought about getting a hot water circulator. You can put it under the sink, and it lets hot water trickle and pump back though the cold-water side. pressures are equal so it just circulated. at some point if no water is used you would have "warmer cold water". we have an upstairs bathroom, and it can be a minute to get hot water for a shower or to shave etc. I just brush my teeth first and that gets us real close. the return water stays in the system and not down the drain. If they planned it when the house was built, it may be a dedicated return line. I would have just teed into the cold-water in. the pump keeps the water going in one direction. check under bathroom sink and see if there is an extra copper pipe on the hot water side in one of them.

beenthere · January 05, 2025, 05:39:33 PM

Could feel the copper pipe going out to learn if it is hot water (likely is) and also feel the pipe coming into the cold water feed at the top of the water heater. That pipe going out the wall is going somewhere, and might be good to find out where to learn more about this "do-hicky"

Mooseherder · January 05, 2025, 05:42:07 PM

I checked the Grundfos website and they say quiet and efficient. That it is not. They also mention some are used to cool ac units. That unit (air handler) is in the attic, go figure. I'll do some more looking into all mentioned including setting the timer. My daughter said she messed with it one time and they had no hot water when needed so she left it on.

doc henderson · January 05, 2025, 05:48:26 PM

COMFORT SYSTEM | Grundfos

barbender · January 05, 2025, 06:03:13 PM

You wouldn't need a circulating pump if it was just a drain.

A circulating loop will come off the drain, and come back to the fresh water inlet iirc. I plumbed one, but never finished hooking it up. The hot water "trunk line" that feeds all hot water fixtures in the house was all insulated to minimize heat loss.

The trunk line was much different than the cold water plumbing I did (all of this was PEX) which used manifolds in the mechanical room with what was called "home runs" I think, which went from the manifold to every water fixture. So there is a seperate leg on the manifold for the kitchen sink, bathroom sink, toilet, etc.

doc henderson · January 05, 2025, 06:21:43 PM

Water heaters drain, not the sink drain. It could have a dedicated line or just go back thorough the cold side.

scsmith42 · January 05, 2025, 06:31:03 PM

That IS a circulating system. I put one in my MIL's house and also first ran across them on a house in Austin Texas build in the late 1950's.

The Texas house did not require a pump - it used convective action to circulate the water. Worked great.

Mooseherder · January 05, 2025, 07:15:10 PM

The copper pipe on the circulating unit is hot. The top right copper pipe on the tank top is warm while the left side pipe is hot/significantly hotter. My best guess right now is it is circulating back to the heater on the cold side intake? I'll mess with the timer tomorrow so SIL isn't taking a cold shower in the morning.

Menagerie-Manor · January 05, 2025, 07:45:02 PM

The pump should have no affect on HW delivery other than a delay if it's just for recirculation.

doc henderson · January 06, 2025, 01:24:24 AM

It should always be hot at the faucet if working correctly. Our sink takes a minute to heat up, upstairs away from the heater. we do not have but were told one could be installed. took a few minutes to understand the concept.

scsmith42 · January 06, 2025, 07:19:36 AM

Quote from: Mooseherder on January 05, 2025, 07:15:10 PMThe copper pipe on the circulating unit is hot. The top right copper pipe on the tank top is warm while the left side pipe is hot/significantly hotter. My best guess right now is it is circulating back to the heater on the cold side intake? I'll mess with the timer tomorrow so SIL isn't taking a cold shower in the morning.

The return typically is plumbed into the tank drain at the bottom of the tank. So the way the pump is plumbed it is pushing water into the bottom (coldest portion) of the tank.

Basically these are set up as a return line from the farthest point of the house.