EcoRenovator - A7 AirTap install (ASHP hot water heater)

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- - A7 AirTap install (ASHP hot water heater) (https://ecorenovator.org/forum/showthread.php?t=2286)

Thanks for the advice. I didn't know about that 3 FPS problem with hot water in copper.

Having faster hot water might be a side-effect of convection flow into about 12' to 14' of 3/4" insulated copper,
between the kitchen sink and the tank.

As an experiment (and to simplify the install), I just want to try it.
If works, it might save 15 or 20 seconds of waiting while running water.
If it works and uses too much power (to keep the pipe warm),
I'll add the heat trap and just live with the hot water delay (that we've always had). :o

Quote:

Originally Posted by Xringer (Post 23297)

Thanks for the advice. I didn't know about that 3 FPS problem with hot water in copper.

Having faster hot water might be a side-effect of convection flow into about 12' to 14' of 3/4" insulated copper, between the kitchen sink and the tank.

As an experiment (and to simplify the install), I just want to try it.
If works, it might save 15 or 20 seconds of waiting while running water.
If it works and uses too much power (to keep the pipe warm),
I'll add the heat trap and just live with the hot water delay (that we've always had). :o

EX, not clear statements.
A natural convection hot water circulation LOOP relies on gravity driving the differential density between hot and cold water. It must be a loop and the heat source must be lower than the loop taps. A forced hot water circulation LOOP has no such constraints.

For a trial, if you don’t have a cold (cooler) water return, you can rig up a garden hose.

IMO, the hot water flow “trap” that you described is a misnomer, it will not prevent natural convection flow in a hot water circulation loop.

So, this type of heat trap won't work?
http://www.energycodes.gov/moodle/mo...iew.php?id=109
Just a scam.gov to add labor cost to the install.?. :rolleyes:
Seems like loops that are lower or higher than the main line, would have some effect.

The warmer water inside the tank goes to the top of the tank..
So, if you have a 3/4" pipe coming out of the top of the tank, going up to the 3/4 elbow going to the kitchen etc,
it sure seems like some hot water is going to rise up inside that 3/4" hot water output pipe..
If it doesn't, this heater will use less power, and we will just have to wait for our hot water.. (But not too long).. :D

I don't think there is going to be any loop effect back to the main.
There is a simple flipper check-valve after the Tee off the main cold water side.
I installed it for the old solar hot water system. It kept the cold water side
from warming up with back-flow from the old 84 gallon storage tank.
(That system was pulled out after it started to fail. Leaks galore).

If the tank was 60 feet away from the kitchen, I would still be reluctant to add a pump and more plumbing.
Since I know from 50 years of experience that adding more components with water pressure inside them, is an invitation to Murphy.
I already get enough water in my basement, from mother nature. :o

Quote:

Originally Posted by Xringer (Post 23299)

Apparently we are talking about two different natural convection phenomena.

1. I’m talking about natural convection driving the flow of water in a closed loop piping system intended to keep hot or warm water at the elevated tap offs. “Heat traps”, loops above the hot water heater, will not prevent this convection flow.

2.The “Heat traps”, loops above the hot water heater as shown in your URL reference, could prevent natural convection currents WITHIN the ¾” pipes from flowing beyond the high point of the loop. These convection currents within the ¾” pipe (if real, I’m a skeptic) would be a hot water stream flowing up on one side within a vertical pipe and a stream of cooler /cooled water flowing down the other side, all within the same vertical pipe. These convection currents are common in open volumes of water but there are minimum volume dimensions below which this phenomenon will not be naturally established. I’m not familiar with what these dimensions might be for water in a ¾” round vertical pipe.

Nice job! How hard was it to cram all that copper into the tank?

Got started on the PEX..

The copper bands are suppose to be 1/8" to 1/4" from the end of the tube..
I wonder if that's +/- 1/16" :o

http://i46.photobucket.com/albums/f1.../P1000709s.jpg

The middle valve is the By-Pass. The other two are cut-offs.

I wouldn't worry about the placement of the copper bands. They seem to work great for sealing things up from my experience.

Quote:

Originally Posted by Daox (Post 23442)

Nice job! How hard was it to cram all that copper into the tank?

It wasn't very hard at all. I just took it easy. When it would stop, I just applied slow pressure until it started moving easy again. (Per the instructions).

My wife was worried about me soldering up near the ceiling, so I picked up some of those cheater connections.
She remembers when we first moved here in 1973, and I was trying to teach myself how to repair 1/2" copper. That wood smoke smell got her real upset.. :p
If you just looked at a pipe, it would burst.. I had to replace every inch of 1/2" copper in the house. :mad:
Shop GatorBITE Push Fit 3/4" x 3/4" Removable Elbow at Lowes.com
Cost me about 15 bucks, but they do speed things up.

I might have this thing working by tomorrow afternoon, if there aren't any leaks.. :eek: