Multiple water heaters with recirculation pump.

[fishdaddy]

I am looking at replacing existing water heaters and have run this by 3 different local plumbers and got 3 different answers. I know this is way more info than you need but each plumber had different reasons for why this and/or other options would not work.

The house has 3 electric tank water heaters (2-50gal. & 1-40gal), with no gas availability. Water heaters are mounted in small separate closets (24"x30") with doors opening to outside of the house. House is single story and shaped like a “U” with 4 bathrooms. The 50-gallon heaters are at each end of the U and are 160 feet apart and the 40 gallon is mounted 45 feet away from the first water heater.

All water lines are run in the attic. House has an open-air tile roof (no plywood or underlayment so exposed to outside temps.), but pipes are wrapped and have a fair amount of cellulose insulation over them. Water is from a deep well with split separate cold-water lines to each heater from the well.

The Kitchen, laundry, and one bathroom are at one end of the U and the master bathroom (with a large 80-gallon Jacuzzi tub) and 2nd laundry room is at the other end of the U. The other 2 bedrooms are near the center of the U.

I am looking at replacing the two 50-gallon heaters with new conventional tank heaters (the old ones are shot) and eliminating the 40-gallon heater by installing a separate recirculation line with a pump between the two 50gal water heaters so that all fixtures can pull hot water from both tanks.

My question is, can a recirculation pump be used to loop water between two tanks that are 160’ apart, and would it be feasible based on the heat loss and electrical expense from that distance and the parameters listed above? Also, would it be better to plumb the loop to the top cold water line or the bottom drain of the tanks?

Alternative options would be appreciated.

 

[Fitter30]

Each heater would need its own recir pump to its own heater. The pump programming would be different times. Three heater could be tied together by piping them reverse return if they were closer together. With a 80/gallon tub 50 gallon heater with 120° water just couldn't fill it at 105° with 65° incoming water.

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[Master Plumber Mark]

Why do you want to do this??
If what you presently have is working good why would you want to go
to all the trouble of running recirc lines and all the other issues just to eliminate a 40 gallon heater??

all the recirulation pumps are gonna do is wear out the heaters and probably wear out the water lines
in your home and cost you more money in the long run

I am just wondering ...thanks

 

[fishdaddy]

I know know this is way more than you are asking for but here are some of the factors that are leaning me towards changing the current heaters/plumbing. I will be living in this house for at least the next 12 years until I can retire. Unfortunately, I live in Ca where energy costs are through the roof and are expected to rise substantially based on current legislation being proposed. I currently have a $650(+) a month electric bill. There is also legislation that will require a water meter on our well and the cost of water will be significant. The previous owner (who supposedly was a contractor) had done two additions to the original house and each time they did an addition they added another water heater. Even with having three water heaters that are fairly close to the bathrooms it still takes a significant amount of time to get hot water to the fixtures due to how they ran the plumbing and how inefficient things are, so needless to say we are wasting a lot of water (which is also straining the septic system.) Most of the pipes in the house are 3/4" old cast iron and with the mineral content from the well the hot water pipes are about a third of the way clogged, the areas that are not cast iron are only 1/2 inch copper, but seem to have minimal sediment in them (so looking at replacing with all 3/4"copper.) Current water heaters need to be replaced anyway (one shorted out, another is rusted through and leaking, and the other is forming rust blisters at the bottom of the tank.) I was looking at on demand units but that would require upgrading the service panel and additional wiring and also would not solve the delay in hot water. I then looked at heat-pump units (as there are rebates for them here), but the water heaters are located in small closets on the outside of the house and would either have to be ducted into the house (which I was told was expensive and would drop the temperature of the vented rooms by 20 degrees, thus increasing heating costs) or would have to be vented to the outside of the house through the doors, where temps in the winter would negate any benefits to having a heat pumps. I have done what research I can and have run this by 3 local plumbers, but each had a different solution to the problem. Based on the fact that I did not have much confidence in the plumbers that I called out and on the cost of the solutions they were offering (one guy wanted almost $15K), I will probably DIY the work (I have done extensive work on other homes in the past with success (including plumbing), so hopefully not getting in over my head. Lol
I am looking for additional advice and/or recommendations as to the best way to proceed.
Thank you again for your time and comments!

 

[fishdaddy]

Why do you want to do this??
If what you presently have is working good why would you want to go
to all the trouble of running recirc lines and all the other issues just to eliminate a 40 gallon heater??

all the recirulation pumps are gonna do is wear out the heaters and probably wear out the water lines
in your home and cost you more money in the long run

I am just wondering ...thanks

I accidentally replied to your question below.

 

[Breplum]

Keep the existing locations, when repiping your old "steel" pipe
(we never had cast iron pipe in CA)
(Cheaper to repipe with PEX btw)
Pipe in a return loop for each stupid WH or one big loop (what most sane people do)
Use a recirculation system with pushbutton or motion sensor or other user activated method like Taco Smart plus, so that water recirculates when wanted. Sure, you have to adjust lifestyle to wait some seconds, but no water wasted waiting and no power wasted running pump when not needed. That is what CA requires now for new construction.
TacoGenie is a poor man's way forward.https://www.tacocomfort.com/product/taco-genie/

 

[John Gayewski]

It very much depends on the piping layout on whether or not you need more than one pump. It's likley you don't need the instant hot water at every fixture but really only some fixtures.

A schematic of the piping and layout is the ONLY thing that can answer your original question.

I would guess you could add some piping and connections and have the water circulate to one heater and be happy and save water.

 

[darbysan]

Late to the party with a thought, but just saw this thread. I have had recirc problems due to copper pipes buried in the slab with no insulation ( think unwanted radiant floor heat!!). It was costly running the recirc, so we found a solution where we could turn on the recirc pump via a remote button ( wireless) which ran the pump for a set period of time ( 30 min for us). Used this for 5 years. We have now switched and have the recirc pump plugged into a smart outlet that works with Alexa. We can ask Alexa to turn on the recirc pump for a set period of time, or we can even set schedules . Works great, and has significantly reduced my electrical bill. As an assurance that the pump gets turned off, I also plug into the same outlet a flashing red light, so If I walk out in the garage and see the light flashing at a time when the recirc should be off, I know I've got an Alexa issue.

 

[fishdaddy]

Late to the party with a thought, but just saw this thread. I have had recirc problems due to copper pipes buried in the slab with no insulation ( think unwanted radiant floor heat!!). It was costly running the recirc, so we found a solution where we could turn on the recirc pump via a remote button ( wireless) which ran the pump for a set period of time ( 30 min for us). Used this for 5 years. We have now switched and have the recirc pump plugged into a smart outlet that works with Alexa. We can ask Alexa to turn on the recirc pump for a set period of time, or we can even set schedules . Works great, and has significantly reduced my electrical bill. As an assurance that the pump gets turned off, I also plug into the same outlet a flashing red light, so If I walk out in the garage and see the light flashing at a time when the recirc should be off, I know I've got an Alexa issue.

Thank you for your suggestions. I called out another reputable plumber to see what they had to say and get pricing. He agreed that hybrid and electric on-demand units were not a good idea based on the situation. He did not agree that I should eliminate a water heater, or to have all the water heaters running in one continuous recirculation loop as he said the distance it would have to travel and heat loss that would occur would keep the water heaters running basically 24/7 in the winter. He suggested just replacing the 3 water heaters with conventional 50 gal. electric ones and combining 2 of them in parallel with a recirculation loop for one side of the house that has 3 bathrooms (one with large jacuzzi tub) and a laundry room, and then putting the other one on the other side of the house that has a bathroom, kitchen, and laundry room with its own recirculation loop (optional based on the distance of use from water heater). He also suggested putting timers on the recirc. pumps to save money, but your idea of the smart outlet may be better. In anycase, I would not be saving any money on electricity so he suggested I look into adding solar to my house based on the number of water heaters, air-conditioning units, and my current electric bill (no he did not sell solar or have a specific company to refer! Lol) He basically wanted $3,000 per unit and an additional $4,000 for the recirc. pumps and running lines in attic, which basically amounted to $13,000. I decided with that expense it would probably be more advantageous to just replace all 3 water heaters myself (cost= less then $3,000) and put the other $10,000 towards solar!

Word to the wise: I had always dreamed of having a large ranch house on some property and the only way I could afford it was to buy an older home in need of lots of deferred maintenance. With looking at having to replace 3 water heaters, 3 air conditioner units, almost every fixture in the house, remodeling bathrooms and kitchen, flooring, pool pump and plaster replacement, paint, and now adding solar (not to mention the strain on my marriage), I am asking myself what the hell did I get myself into! As they say, be careful what you wish for! Lol

Anyway, thank you again for your comments and suggestions.

 

[Fitter30]

Thank you for your suggestions. I called out another reputable plumber to see what they had to say and get pricing. He agreed that hybrid and electric on-demand units were not a good idea based on the situation. He did not agree that I should eliminate a water heater, or to have all the water heaters running in one continuous recirculation loop as he said the distance it would have to travel and heat loss that would occur would keep the water heaters running basically 24/7 in the winter. He suggested just replacing the 3 water heaters with conventional 50 gal. electric ones and combining 2 of them in parallel with a recirculation loop for one side of the house that has 3 bathrooms (one with large jacuzzi tub) and a laundry room, and then putting the other one on the other side of the house that has a bathroom, kitchen, and laundry room with its own recirculation loop (optional based on the distance of use from water heater). He also suggested putting timers on the recirc. pumps to save money, but your idea of the smart outlet may be better. In anycase, I would not be saving any money on electricity so he suggested I look into adding solar to my house based on the number of water heaters, air-conditioning units, and my current electric bill (no he did not sell solar or have a specific company to refer! Lol) He basically wanted $3,000 per unit and an additional $4,000 for the recirc. pumps and running lines in attic, which basically amounted to $13,000. I decided with that expense it would probably be more advantageous to just replace all 3 water heaters myself (cost= less then $3,000) and put the other $10,000 towards solar!

Word to the wise: I had always dreamed of having a large ranch house on some property and the only way I could afford it was to buy an older home in need of lots of deferred maintenance. With looking at having to replace 3 water heaters, 3 air conditioner units, almost every fixture in the house, remodeling bathrooms and kitchen, flooring, pool pump and plaster replacement, paint, and now adding solar (not to mention the strain on my marriage), I am asking myself what the hell did I get myself into! As they say, be careful what you wish for! Lol

Anyway, thank you again for your comments and suggestions.

Looking for 30+ acres in the country 19 years ago and was still working. So i wasn't not thinking the my standards and the inspector were very different and the inspector recommended wasn't very good. So the house i bought and my neighbor built it. Knowing what level , plumb and square is he didn't. There is not anything I've open up has been a nightmare. Had the house for 19 years full time 12. Tell people all the time if you looking outstate unless you build buy a doublewide.