The stock nipple isn't brass. I think the tank is steel, so it shouldn't be that dissimilar.?.
The HD price for brass was over $17.. Black Steel was $2.24 :p

porcelain
 

I think it's some kind of baked-on porcelain coating.

Never really had one of these things before, but I've read, the anode
should be inspected every 6 to 12 months. I think this one might be magnesium.?.
I saw some pics of anodes that looked half eaten. :eek:

I want to pull this one out for a peek and put it back in with Teflon tape.
(So I can do inspections later on).

I'm going to look at wiring the elements to use about 1.2kw at 120vac.
Just in case the A7 needs a little help..

They used to have the installation manual up on their web page. IIRC it said to disconnect the regular heating elements. Maybe because they interfere with the temp sensor? I don't know.

WRT the anode, I was talking about the anode rod for the boiler that you're having rust problems with. Maybe a new anode would help. Your new heater should have a new anode in it already. If you change the anode, it has to have an electrical connection to the tank - that's how it sacrifices itself galvanically. So teflon tape might not be so good.

P.S. You might want to make heat-trap loops in the lines since you took out the heat-trap fittings.

Correct
 

I went back and read it again.. They don't want any power going into the HW heater...

Warnings
When installing the AirTap™on a gas or electric water heater, disconnect permanently the gas or power supply to the water heater while the AirTap™is being installed. The original gas/power supply to the gas/electric water heater shall remain disconnected after installation.

Seems odd to me. The Hybrid units being sold these days are using both modes of water heating..

Maybe the A7 is so good, they feel you don't need alternate heating coming in. :rolleyes:

I guess using AC (or solar PV) is something to look at later.
I don't foresee needing alt-heat for a good while.


Now, I'm trying to figure out the best way to incorporate heat traps in the lines.
My GE manual shows a 6" (minimum) down loop on both water lines.
I could do it with PEX elbows, but I'm thinking some (four) 90 degree PEX bender brackets might be better.

A5150750 - Uponor (Wirsbo) A5150750 - 3/4" Plastic Bend Support
http://s3.pexsupply.com/images/produ...a5150750-3.jpg
I could run the Pex up 7.5" above the 3/4" copper, bend flat flat (against the kitchen sub-floor) and bend it back down to the copper..
That would avoid the use of a lot of elbows and the problems they cause.

And just what is a heat trap in a water line? I’d like to trap some!

My GE hybrid has both and can be switched to electric, heat pump or both for "high demand".

bender brackets
 

Yeah, and that's why I think it would be pretty weird that the A7 would be installed,
so it couldn't run the heating elements at all. :confused:

IMO, the heating elements on my setup should come on, when the temperature
drops below my choice of set-point.
If I run them at 120vac, it's not going to cost a lot to assist the A7.

~~~

I took it easy on my sore back all weekend, did the recommended stretching,
went for a slow 3 mile walk on Sunday evening..
And today, my back is hurting more! :mad: It stinks to be getting so old..
Got a few easy things I can do today. Slow progress is better than none..

I ordered four of those 90 degree PEX bender brackets for the heat traps last night.
(Ebay total $5.98) Should be here by Thursday.

Edit: The PEX 90deg brackets came today (Wednesday). Which has me thinking that I may need more 3/4" PEX.. I only have 10 ft..

Probable the reason they want you to disconnect other heat source because what if your thermostat fails? HWT can reach over 100 C (boiling water + pressure). You have their refrigeration lines (full of liquid refrigerant) inside this super hot water. Think what is going to happen next???

The TPV will open and vent the hot water.

The hybrid units likely have an HX with refrigerant too. I wonder how they would deal with 100C?

I've been thinking about this problem for a while. It seems like any system without
a double-wall/(middle wall vented) using refrigerant to heat water, could fail
and inject high pressure gas into your storage tank and/or your house water lines..
I hope my 100 PSI T&P valve will do the job for R22.. :)

If I used the elements in my tank, I would not run them at 3.5kw.
But, even at 1,000 watts. Overheating might be a problem.



So, if I decide to hookup power (even my 800w of PV), I'll do some testing
to see if it's possible to over-heat my 40 gallons of water (using low power)..
If it is, I'll follow the AirTap no extra power rule..

With the limited amount of solar (5 hours a day max), PV might be a safe bet.

When I checked my PT valve it was seized because I have en expansion tank so it never opens.

But even working TP valve is set @ 210F and 150PSI. Your unit has designed pressure that is printed somewhere. Usually for R22 unit it is in 400psi range. R22 @ 210F will have 600-700psi or even higher (most pt charts are only up to 150F). This is much more than designed pressure.

This unit is meant to be installed on somebody's HWT. They don't know anything about it.
Everything can fail and nobody wants to be responsible for somebody's faults....

Now when you design complete unit from scratch you can add extra safety locks to make sure temperature in HWT NEVER goes above let's say 145F. Is it possible? Yes. This is why complete unit (HWT + refrigeration unit) have "hybrid" mode.

Xringer, if you ever want to add "hybrid" feature to your HWT you can do it but you have to make sure you have extra safety controls. You can add another thermostat or even 2 in series. This thermostat will be set higher than regular but bellow design pressure (just check PT chart). If temperature for whatever reason rises above it's settings it will disconnect or even lock out your elements.

Here is online PT calculator. Very basic but easy.

http://fridgetech.com/calculators/

"hybrid" feature
 

Not thinking about the "hybrid" feature now..

But, it looks like it wouldn't be too hard to put the two built-in Tstats in series.
If either one opened, it could shut off the power.

It would be pretty be simple to design a dual safety circuit.
(A redundant backup system that would work in parallel).
So, you would have to have dual failures to get over-heating..

But, nothing electronic is ever 100% reliable. (due to lightning storms). :eek:

I agree with you about electronics but go the other way. Just put contactor that closes your main line (L1 L2) and connect its coil(line voltage or 24V in series with fusible switch). Fusible switch will melt inside at set temperature and lock out the contactor. If you want you can put 2 fusible switches in series or 3 or..... They are precisely calibrated and you can choose them with 3-5 degree difference. One of them will work 100%

I am sure the capacity of this heater is not going to be enough. It is just a matter of time when you start cursing in the shower...... and add "hybrid" mode.....

It really sucks to think about if you have enough hot water in your tank. Life is too short to think about things like this. Just do it right and forget.....:)

Anode inspection
 

I wanted to do an Anode inspection, mostly just to see if it was going to be possible to remove it.

First, I had to return the 1" socket for a 1" 1/16" socket.
(I found out the hard way, instead of looking it up on the web)
http://waterheatertimer.org/images/A...-image-530.jpg
Notice the Cheater pipe.. :cool:

Then, I had to use the extension pipes again. Only this time it was a lot harder.
That Anode was super tight. These old arms are hurtin! I'll be lucky if I can go knock down some Candle-pins this week!

http://i46.photobucket.com/albums/f1...W/P1000654.jpg

http://i46.photobucket.com/albums/f1...W/P1000656.jpg

It looks like a solid aluminum rod.. But, magnesium looks the same to me..
The rod had two different layers of gunk on it (black & green).
I cleaned it up and re-installed using Teflon tape & silicon oil.
It went in nicely and felt like it cranked right to the bottom.

Did some reading on the web and found Teflon tape is okay to use on anodes.
I checked with my ohm meter and the cap is a dead short to the AC ground.

~~~
I'm getting this done very slowly.. And now it's going to be even slower!
Due to unforeseen problems, my DIY time is going to be cut way back for a few weeks. :(

FYI, Plate HX on eBay, 23 available for cheap
 

Can’t get the 20’ cu tubing evaporator snake in my HWH so am going to use this external HX as the evap. I already have a HW circulation loop with pump for my in floor heating system. My $20. offer was accepted. The stainless tubing on this 10 plate HX is standard ½” tubing OD, 0.630” so various fittings can be silver soldered or brazed to the cut off tubing, AR.

Stainless Steel Brazed Plate Heat Exchanger 8x3x1.5 In | eBay

Hi to all
 

Just found this site and hope it adds some much appreciated thoughts and designs to my Feeble brain . I'm interested in a small geo unit for a garage . Today it is 107 on the thermometer outside and 99 in the garage . I will enjoy looking at all the posts and great wealth of info already shared on this site . Thanks to all and have a blessed day.
:thumbup:

If your HWH is in the garage, consider this A7 ASHPWH, currently at a good closeout price on eBay.

If it's 99F in the garage, I'm sure the A7 could make abundant hot water..
Plus, it should cool down the garage a bit too. (Until the storage tank got hot)..

If you wanted to work in the garage, I would consider insulation and buying an
inverter mini-spit AC (or AC+Heat model).

What about pressure specs??? It was used as water/ oil HX. You want to use it for pressurized refrigerant right?

Sure, why not? By design a plate type would be difficult to make without 4 to 500 psi working pressure. If one would fail, the leak would be to the outside, not across the plate.

I looked at a bunch of HX units before I found one that was suitable for R410A pressures.
http://ecorenovator.org/forum/geothe...hw-heater.html

http://i46.photobucket.com/albums/f1...9647635_tp.jpg

I looked at the specs at DudaDiesel - Biodiesel, Chemical & Solar Supplies, Alternative Energy Store
and didn't really see very many small HX units, that could handle higher pressures.

I plan to use my Ebay HX, if my A7 copper loop doesn't work out.
But, chances are, it will do just fine. (fingers crossed)!

No-waiting hot water?
 

Project is still on slow-cook for a while.. :(

MBATR, I've been thinking about a couple of items.

1. How am I going to lift a large 100+ pound tank up in the air and sit it down,
inside the aluminum drain pan, without crushing the sides of the ($20) pan??
Ropes and pulleys?

2. We had a discussion a while back, about No-waiting hot water. Instant warm water at the tap!
I'm wondering, if I skip using a heat trap on the output side of the tank..?
And allow a small amount of warmed water to fill up the pipe (insulated) going to the taps & outlets..

It seems like an easy way to get hot water faster, but also seems a bit wasteful.
But, I should be able to determine the cost of 'fast' hot water pretty easily.
If it's too high, (over 2kwh/day) I can add a heat trap to the PEX line.

Comments Please.

1. Don’t lift, walk! Walk it up on pieces of 2x4 one or two legs at a time. May need help to steady the tank and move blocks around.

2.Natural convection flow only works if you have cold return piping from the most distant tap with check valve, and the top of the tank is lower than the piping loop to the taps.

I think it sounds really wasteful unless you really insulate the pipes very well which sounds like a pain to me. I don't think I'd bother. Is it really that bad to have to wait a few moments for hot water?

I've had experience with 'Natural convection flow' when I installed my old 84 gal solar tank.
The hot water pipes are insulated, and I'm not sure if I'll get enough 'flow' to give us anything but lukewarm water quickly.
But, in the middle of the winter and I want to quickly splash some water on my hands, lukewarm is way better that 64F water.. :)

I'll be able to measure the heat loss by allowing convection flow for 8 hours
(at night) while measuring how many kWh used.
The next night, I can close the output cut-off valve and measure the kWh
used without any convection flow. The difference will be the loss.

~~~

I was thinking about the 2x4 idea. The pan is almost 3" deep so, I would need something taller to ramp on.

But, maybe I could grease up the bottom of the pan and then use a 4x4 next to the pan.
I'll take the tank over with the 2-wheeler, balance it on the 4x4,
remove the 2-wheeler and then tilt the tank into the lid and slide it
over while holding up the back edge, so it won't drop on the pan edge.
That way, I won't have to hold the whole weight of the tank..

Consider a small circ pump. Grundfos Series UP is designed just for this purpose, 3 GPM, 5¼’ head, built in 24 hr adjustable timer, full union with isolation and check valves.

Don’t use an oversized circ pump for hot water in copper tube! The cu will pit corrode at hot water flow velocities over about 3FPS. BTDT! Google it.
FYI, 1 GPM in ¾” type L Cu tube = 2 FPS flow velocity.

berniebenz,

Sounds like you really know your stuff.

It would be really useful to everyone if you wrote up a circ pump selection guide... maybe like the 10 things you need to know, or something... just a suggestion.

I think that there are plenty of us here that could benefit from your knowledge.

In fact if you PRESS HERE it will open a new thread for you to do one.

Don't forget to give it a title!

Best,

-AC_Hacker

Thanks AC,
But sizing circ pumps is no different than any other pump App. Knowing what you want to do, the system constraints and the search for economic possibilities.

The hot water copper corrosion problem I learned from experience. Pin hole leaks developing in 10 year old copper. A Google search uncovered the high velocity hot water corrosion problem and tested velocity limitation solutions. A well defined temperature, velocity related problem with copper. Just a heads up to store away.

Not a HVAC tech, just an old school engineer. 100% DIY shows up undaunted limitations.

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

Heat traps
 

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.

Back to work!

In the pan..
http://i46.photobucket.com/albums/f1...W/P1000697.jpg

Leveling support arms.
http://i46.photobucket.com/albums/f1...W/P1000698.jpg

Ready for A7
http://i46.photobucket.com/albums/f1...W/P1000700.jpg

Heavy box for an old guy..
http://i46.photobucket.com/albums/f1...W/P1000701.jpg

HX loop ready to feed.
http://i46.photobucket.com/albums/f1...W/P1000702.jpg

Loopy!
http://i46.photobucket.com/albums/f1...W/P1000704.jpg

Almost done!
http://i46.photobucket.com/albums/f1...W/P1000706.jpg

Tight!
http://i46.photobucket.com/albums/f1...W/P1000707.jpg


Where's the PEX?
http://i46.photobucket.com/albums/f1...W/P1000708.jpg

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.

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: