A7 AirTap install (ASHP hot water heater)

[Xringer]

Looks like a bad PEX crimp on the cold water input.
I did a quick inspection today, and noticed a brown stain on top of the tank.
Pulled off the insulation and saw the leak is at the PEX attachment point.
It looks like it's been weeping for at least a month.
The iron pipe is a mess of rust and it will have to be replaced.
Of course the nipple at the leak point will need replacement too.

[Vern2]

If nothing else, it was a good dielectric connection.

[Xringer]

I may not have used the best connector..


I may have used this one (or one like it)..

SharkBite 3/4 in. Brass Female Swivel Adapter-UC530LFA at The Home Depot

a Two piece fitting


When I should have used a 1 piece fitting??

SharkBite 3/4 in. Brass Barb x Barb Female Adapter-UC088LFA at The Home Depot



Anyways, the leak was pretty serious, so I had a rag around it, while the dish washer was still running..
The rag was getting soaked.. I started wondering if it was the PEX crimp,
or was it due to a seam leak in a two piece fitting??
So, I put a wrench on it. It turned easily! Kinda makes me wonder
if the compressor vibrations loosened the fitting??

The leak seems to be minimal now (or stopped), I've got a dry rag on it,
and will check for wetness later this afternoon..

Edit: 6:50 PM
The leaking has completely stopped. I guess Teflon tape makes plumbing parts come
apart, a little too easy..?.
Maybe I should put a mark on the part, so I can see if it rotates as the A7 racks up the hours?

[Xringer]

It kept on leaking, very slowly.. About 1 drop per day.
Went to HP today and got the right part..
I'll stay away from those swivel connections from now on..



I turned off the solar PV yesterday and put the A7 timer on standby.
Drained off a couple of gallons with the bottom tap.

Cut the copper PEX bands with a Roto-Zip cut-off wheel. The rest was pretty easy.
I hope this one is going to be tight.

[Xringer]

Got the CAI board hung up next to the A7..



Temperature sensors:
#1 is outdoors
#2 is the tank
#3 is the basement
Humidity sensor is outdoors.



Here's the start up PLC program..
I'm going to back to basics, to get back up to speed..

START
SET VAR1 T1
SET VAR2 T2
SET VAR3 T3
SET VAR4[30] H1
SET VAR6 CH
SET VAR7 CM
END

Variable #6 is the hour of the day.
Variable #7 is the minute of the hour. (It was 21:28 or 9:28 PM)


Two Goals:

Anyways, the plan is to write a control program that will use the X10
transmitter function, to control the A7 and also the basement ventilation fan.

I will try to use the Clock data to in subroutines to make time-delays,
since I don't want the X10 turning the A7's compressor on & off, too quickly.

I'll also want to control the basement fan, based on the hour of the day & outdoor humidity. (Don't want to bring in damp air).

Later this winter, I'll want to add a routine that looks at basement temp vs outdoor temp, and runs the fan,
until the basement temperature goes below my setpoint.
It will stop the fan, and allow the basement to warm back up.

[AC_Hacker]

Originally Posted by Xringer

Got the CAI board hung up next to the A7...

I think it's great that you're moving into new territory with the CAI, it has so much potential.

What problems are you trying to address here?

-AC

[Xringer]

I've been running the basement ventilation on a timer.
The problem with using a timer is, it's doesn't turn off during a rain storm.
Causing the blower to suck a lot of moist air into the basement.

Using the CAI to control the ventilation blower (via X10), I should be
about run it during the day, and not run it when the RH is over 70%.


~~~

I've also been running the A7 on a timer. It was set to come on around 13:00 each day.
The idea was to give the Solar PV boost a little time to work, before using the A7.
And, the idea worked, on most days, but on overcast days? Not so well.

So, I want to use the CAI to monitor the solar conditions/tank temperature.
Look at morning sun power and 'predict' a nice solar day.?.
(And just in case, be able to see that my wife is doing a early morning laundry).

If possible, I don't want to run the A7 early in the day, if it's going to be a nice sunny day.

Today, I'm using the X10 remote..

[Xringer]

Programming is coming along very slowly!

I re-insulated the repaired leak site. I had left the area bare, to make sure there would be no H2O re-occurrence.

Checked the temperature last night at 7PM and the tank was 138F (all solar PV heating)
and this morning at 10:30AM, it was 122.5F. It lost 15.5 degrees in 15.5 hours.

It's about 11PM now, and the sun is started to warm the tank back up..
Currrently at 124.5 F

The DS1820/DS1822 based digital temperature sensors seem to be very accurate.
Not sure how these will work long-term. So far, the only problems have
been with the CAI controller firmware. Configuration losses.
Or, I could be having RFI problems from the local AM station..


Wrote some code to test.. This should control the basement ventilation fan,
and only come on, when the air is dry..

START
SET VAR1 T1
SET VAR2 T2
SET VAR3 T3
SET VAR4 H1
MUL CH 60 RAM8
ADD RAM8 CM VAR8


TSTLE H1 66 ~~~~~ is RH Less than 66%? if it is, don't skip the next line..
CALLSUB FAN_ON ~~~~~ calls subroutine to turn on the fan.


TSTGT H1 68 ~~~~~ is RH GreaterThan 68%, then don't skip the next line!
CALLSUB FAN_OFF ~~~~~ Shuts off the fan, using X10 command.
END


FAN_ON:
X10 2 7 ON ~~~~~ This House code 'C', and module code '8'
INC VAR5 ~~~~~ (var5 is visible on the status display. Helps see whats up).
SET RAM7 900 ~~~~~ Setting the timers subroutine to 900 seconds or 15 min.
CALLSUB TIME10 ~~~~~ calling the time waster routine.
SET RAM7 0 ~~~~~ Always clean up after using.
RET


FAN_OFF:
X10 2 7 OFF ~~~~~ Sending the off command to X10 appliance module.
INC VAR6 ~~~~~ incrementing var6 so we can see if the code is working (or hungup)
SET RAM7 180 ~~~~~ Setting the time to 180 seconds on this one. (in case of rain)
CALLSUB TIME10
SET RAM7 0 ~~~~~ clean up
RET



TIME10:
SET VAR7 0 ~~~~~ Set the loop counter to zero to start.
MIDEE:
DELAY 1000 ~~~~~ Stop here for 1 second (1,000 milliseconds).
TSTEQ VAR7 RAM7 ~~~~~ check to see if loop count is complete, if not skip the next line.
RET

INC VAR7 ~~~~~ increment loop count by one .
GOTO MIDEE ~~~~~ Jump back up to the middle of the timer routine..

Once the inc var7 hits the 'seconds' asked for by the caller, there is no line skip and the RET (return command) ends the looping..

[brogsie]

Xringer Thanks for documenting your install.
I installed an a7 on my superstor storage tank. I really like it but recently the t stat seems to have failed. The unit stays running all the time and cannot be shut off with the switch. the tank overheated and set off the pressure relief valve. Airgenerate sent me a new t stat but it looks difficult to change out. My unit has the extra black wires on the back. I was hoping to be able to use the t stat on the storage tank. Anybody know how to bypass the t stat on the unit and use the extra wiring? I have a message in to Airgenerate but have not heard back yet.

[Xringer]

Originally Posted by brogsie

Xringer Thanks for documenting your install.
I installed an a7 on my superstor storage tank. I really like it but recently the t stat seems to have failed. The unit stays running all the time and cannot be shut off with the switch. the tank overheated and set off the pressure relief valve. Airgenerate sent me a new t stat but it looks difficult to change out. My unit has the extra black wires on the back. I was hoping to be able to use the t stat on the storage tank. Anybody know how to bypass the t stat on the unit and use the extra wiring? I have a message in to Airgenerate but have not heard back yet.

Those 'extra wires' were discussed back a few pages..
http://ecorenovator.org/forum/geothe...heater-28.html




It sounds like your built-in T-stat is shorted. Contacts welded together.
You will have to unplug it (one side will do) and connect those two
(extra) black wires to the T-stat in your heater tank.



To disarm this device, cut the black wire, between the T-stat and the screw-wire-connector..
Cap the cut wires, so they can't short to the chassis.