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Hot water delay to bathroom

marktheshark's picture

I'll try to be brief.  Older house, long run to upstairs bathroom.  Recent installation of a Navien propane fired combo unit.  Water is nice and hot once it gets there, but takes more than a minute and the same to the kitchen.  Old furnace was oil-fired and was in line with an Amtrol WH-7  Boiler Mate hot water maker.  Right now the old furnace and the Amtrol are still in the basement, nonfunctional.  Would there be any advantage to keeping the Boiler Mate hooked up in conjunction with the Navien?  Could I put an undersink circulator in the upstairs bathroom to keep a loop going between bathroom and Amtrol without affecting the sensing of the Navien?  I am the homeowner and my understanding of HVAC is very limited, so please speak slowly.  Thanks in advance for any help. 

The simplest solution might (post #207393, reply #1 of 9)

The simplest solution might be to install a very small electric WH (like 2 or 3 gallon size) under the sink. The supply to the WH would be what is now the hot supply to the sink, and the hot outlet of the WH would become the new supply for the sink.

This arrangement would, of course, only ensure instant hot water to the sink, but since the sink is often the first thing to be used, the main hot line to the bathroom group would be heated by your Navien main WH. And, waiting for hot water at the sink is what people usually find most objectionable.

"I am the homeowner and my (post #207393, reply #2 of 9)

"I am the homeowner and my understanding of HVAC is very limited, so please speak slowly."

I'll type real slow just in case you don't read too fast either.

 

A hot water recirculating loop would help, since your bathroom is on the 2nd floor. It would take a plumber to do, but takes no electricity.

How about the water maker? (post #207393, reply #3 of 9)

I appreciate the responses.  Would there be any advantage to putting the Amtrol Boiler Mate in-line with the Navien, especially if there were a circulating loop going to the bathroom?

You would probably lose a lot (post #207393, reply #4 of 9)

You would probably lose a lot of heat with that arrangement..

You basically have 5 (post #207393, reply #5 of 9)

You basically have 5 choices:

  1. A continuously running hot water loop.  Requires that a second pipe be installed to return the "cold hot" water to the water heater, along with a pump either at the heater or at the end of the line.  Expensive to install and to operate.
  2. The same as 1 only with a thermostat and/or timer that shuts down the pump when the pipes have gotten hot enough (and maybe also shuts things down overnight, etc).  Saves some operating cost but still expensive to install.
  3. A "Taco" (one brand) pump at the furthest sink, rigged so that it pumps water from the hot pipe to the cold pipe.  The pump is started by pushing a button (or, optionally, by a timer that sets it off in the AM) and it runs until a thermostat senses hot water.  Fairly inexpensive to install and not terribly bad energy-wise, but some people are turned off by the (relatively remote) chance of warm water from cold water faucets.
  4. A separate 1-5 gallon electric water heater located near the problem faucets, and rigged to be fed from the hot water heater.  Probably more expensive than 3 to install, and probably about the same energy-wise.  Requires a significant amount of space that may or may not be available in a base cabinet, at the top of a closet, or in the attic.  But relatively predictable and trouble-free.

And, as promised -

        5.  Don't worry about it.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

>>>A separate 1-5 gallon (post #207393, reply #6 of 9)

>>>A separate 1-5 gallon electric water heater located near the problem faucets

I've always wondered if you'd ever get a ROI on one of these.

I know that there is a collosal amount of water and energy wasted while people wait for hot water to arrive from the basement. Our kitchen has about a ten second delay. Do you happen to know of any data?

There's probably too much (post #207393, reply #7 of 9)

There's probably too much variation from one case to the next for any data to be reliable.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

My answer to that is: very (post #207393, reply #8 of 9)

My answer to that is: very doubtful that you'd get a ROI to pay for just about any re-heat or re-circ system. The small WH would likely rust out just about the time you might be approaching payback.

This is a case where convenience trumps savings.

The best bet, because it's (post #207393, reply #9 of 9)

The best bet, because it's cheapest to install and runs only intermittently, is probably the push-button Taco pump.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville