Hot Water Loop working TOO well.
I have a house with pump driven hot water circulating loop. The system is working TOO well. I have to run the cold water on my faucets for several minutes before the water is cool. This situation defeats any conservation gains the system should offer. Is the pump circulating too much fluid? I think I may have a bypass valve system. Is there a way I can reduce the amount of fluid that is bypassed to the cool water line? Do the pumps typically have a set output, or can I reduce the flow rate without having to purchase a different pump? Thanks for your help
Replies
What are the details of your system?
Does this have a 3rd pipe return?
Is this an addon system using the existing hot and cold water lines? Most of the commercial systems of that type use either thermostatically controlled valves or pump control.
Where is the pump?
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
The pump is on top of the hot water heater. I cannot identify a third line. I suspect that the system was an add on. Thermostatic bypass systems are fairly new right? I would then guess that the system was driven by the pump. I can't even find the bypass. I thought it would be under the sink, but no such luck.
What is the pump connected to too and how does it fit into the water heater.I can't figure out how it would pump anything without either a bypass at the far end or a 3rd line for return..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Sounds like the system is using the cold water supply for the hot water recirc. line and it should have it's own line. If adding a hot water line is not possible, one solution might be a pump control (I'm thinking out loud here). The pump comes on when you want it to (e.g. a wall switch), but when the hot water gets to the faucet, the pump shuts off. Just heard a presentation on this recently. This way the return line doesn't fill w/ hot water ... just the cold water from the hot water line until the hot water reaches the point of use.
Details are missing here ... I can find my notes at the office if you are having difficulty and refer you to this company that specializes in recirc system pumps/controls. It sounded like a new twist to an old system.
I can't get any pictures up, but the solution you've described makes sense. Does the pump turn off with a thermostat, or is that done manually. Can you pass along the contact info of the company offerring such a system. Thank you very much.
I'll send myself a note to check my notes at the office and get back to you w/ some details. Not positive it would be the ticket, but it might be right. One thing I do remember is that their system used a larger pump for quicker hot water demand, but the concept is simple enough and may work for your situation (it may be as simple as you installing the control or switch. I'll be back at you.
got a pic?
check out this link: gothotwater.com
Generally, this unit turns on ... uses the cold water for the return, but as soon as the pump senses hot water, it shuts off ... that way you don't fill the cold water line w/ hot water. It can also use some manual switches (including a remote control style) ... not positive how they work ... guessing if you anticipate using hot water, you flip the switch ... pump turns off when it senses hot water. Pump mounted at the farthest fixture (not at the water heater).
This is nice as the pump isn't always on like I'm assuming in your system ... which wastes energy (pump and hot water radiation from piping) ... while still saving water run time until it gets hot. It uses a larger pump than what you have ... for quicker response times (less time to get hot water each time you use it).
Hope this gives you some ideas. The key is to shut the pump off when the hot water reaches the fixture/sink. Concept is simple ... you might be able to adapt it.
I set up my domestic hot water system with a pumped recirculation line, one coming back to the water heater from each of the farthest points in my house. I never run the pump and throtte down the isolation valve. Gravity does more than enough to keep the hot water supply pipes warm. If your pump "works too well", turn it off and see how gravity alone works.