A7 AirTap install (ASHP hot water heater) - Page 28

Morphers · 05-06-13, 11:38 PM

Hi,
Wondering what you think about using the airtap in the same room with high heat producing computer servers running 24/7. Of course along with water tank. I have a gas fired on demand water heater and I am wondering when I get a tank for the airtap should I just completely bypass the on demand or can I use the air tap and storage tank to preheat the water going into the on demand heater? Everything is in basement in utility room. I live in Minnesota too.

Thanks

Xringer · 05-07-13, 01:14 AM

Not sure about pre-heating. How well it would work depends on a few things.
How large are the demands going to be over what time span?
Would there be much loss of water temp if your gas heater was
set to a lower temperature? (In the HX of the gas heater).

If you wanted to leave the gas running all the time, leaving the A7 (pre-heat)
set to a lower temp, that might work pretty well.
Since the gas heater would only have to bring up the temp
of it's input water just a few degrees. (using much less gas).
Or under monster demand, if the A7 fell behind, the gas could do the whole job..

Running the A7 in a server room sounds great. It will cool the room as it removes the humidity.

Get em (new model) while their still in stock.. Power Mizer H2O Heat Pump Water Heater | eBay

Xringer · 05-14-13, 11:20 AM

http://i46.photobucket.com/albums/f1...psb7b37684.jpg

As the weather warms (slightly) we are outdoors more, bike riding more
and that's increasing our hot water use by at least 30 percent.

With mixed weather, the A7 has been using 0.5 kWh per day off the grid.

PV hot water heating helps!

AC_Hacker · 05-14-13, 11:43 AM

Quote:

Originally Posted by Xringer

...With mixed weather, the A7 has been using 0.5 kWh per day off the grid... PV hot water heating helps!

Do you have enough data yet to be able to calculate how may actual kw-h/day or BTUs/day the PV system is giving you in hot water (not estimated or measured at the panel)?

-AC

Xringer · 05-14-13, 03:13 PM

Not a lot of data with the new dual array setup..

Last August: http://ecorenovator.org/forum/geothe...html#post23840

23 days (or 552 hours) of operation and the A7 has run for almost 38 hours, Using 22.65 kWh.
That's almost 1kWh ($00.1633) per day.

We were using about 1kW per day, and now it's about half that.

This kind of data isn't easy capture, since hot water use is so erratic.
Plus, when it's hot and sunny out, we might start using twice as much hotwater,
canceling out the solar gains, as we get them!

I'm busy enjoying the nice weather, on the bike trail every chance I get.
This DIY project is kinda on the back burner unless there are problems..

But, I'm still thinking of using the CAI board and those DC current sensors
to measure the PV power during the day and try to save an average wattage.
I can use the CAI email feature to shoot out an email each day,
and convert the numbers into usable data, somehow..

I think there might be a way to have Excel just read the CAI page
during the day and create a plot.. I would have to manually enter
the KilaWatt meter kWh number.
I'm so retired and this seems so much like work!

ctgottapee · 05-22-13, 03:22 PM

Quote:

Originally Posted by Xringer

Get em (new model) while their still in stock.. Power Mizer H2O Heat Pump Water Heater | eBay[/url]

I got one and it appears solid and a great deal.
It isn't very 'new' though, the label says it's two years old.

This version also has an additional set of 2 wires coming out, that were capped off. They appear to be a way to override the internal thermostat but its use is not documented.

Xringer · 05-22-13, 06:39 PM

Quote:

Originally Posted by ctgottapee

I got one and it appears solid and a great deal.
It isn't very 'new' though, the label says it's two years old.

This version also has an additional set of 2 wires coming out, that were capped off. They appear to be a way to override the internal thermostat but its use is not documented.

Nice! Do you plan on installing soon?

Does it have a diagram on the side of the cabinet?

It might tell you you what those two wires do..

ctgottapee · 05-22-13, 07:23 PM

Quote:

Originally Posted by Xringer

Nice! Do you plan on installing soon?

Does it have a diagram on the side of the cabinet?

It might tell you you what those two wires do..

Yes it has that diagram, but mine has some additional dashed lines probably indicating this wire [I'll work on getting a pic up]
I asked the seller and he contacted Airtap and was told it was thermostat control related.

Installing within a month; need to lug it downstairs, and prep first. The units legs appear to be a bit wider than the marathon heaters top base, so I have to play with this a bit....

Xringer · 05-25-13, 09:43 PM

Side by side..

That top thermostat(T-stat) the one you set with the temperature dial. (It's fed by a skinny copper tube fed into the tank).

The two wires are for adding a second thermostat, in parallel with the existing T-stat.

If your hot water heater tank has an unused thermostat, you could connect it to the BL & BR wires..
I really don't see the point of the two extra wires.. They aren't needed..

Maybe using a T-stat on the bottom of the tank would make the until work better.?.

ctgottapee · 05-28-13, 07:15 PM

Quote:

Originally Posted by Xringer

I really don't see the point of the two extra wires.. They aren't needed..

Maybe using a T-stat on the bottom of the tank would make the until work better.?.

The wiring seems odd too, as a hot water thermostat would connect to trigger, but the way these two extra wires are set up is to run when disconnected.
I assume you just turn the airtap's thermostat to 130 which equals always on, and let the other thermostat do the work.

Another option would be a time of use timer to run during off peak hours. My water heater is set up like that now. Top element at low temp in case water runs low, bottom element at a bit higher temp during off peak to generate cheap heat at night.

I will probably keep the top element wired like this as a backup.

Clearly some end buyer of whomever produces these requested this feature, and they shipped the changed out with all of them. Probably means there are international buyers of this unit selling it or just installing it. That is what the 'power mizer' people use to be, now they are just selling off old stock

05-06-13, 11:38 PM	#271
Morphers Lurking Renovator Join Date: May 2013 Location: Owatonna Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts	Question about using alongside server Hi, Wondering what you think about using the airtap in the same room with high heat producing computer servers running 24/7. Of course along with water tank. I have a gas fired on demand water heater and I am wondering when I get a tank for the airtap should I just completely bypass the on demand or can I use the air tap and storage tank to preheat the water going into the on demand heater? Everything is in basement in utility room. I live in Minnesota too. Thanks

05-07-13, 01:14 AM	#272
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Not sure about pre-heating. How well it would work depends on a few things. How large are the demands going to be over what time span? Would there be much loss of water temp if your gas heater was set to a lower temperature? (In the HX of the gas heater). If you wanted to leave the gas running all the time, leaving the A7 (pre-heat) set to a lower temp, that might work pretty well. Since the gas heater would only have to bring up the temp of it's input water just a few degrees. (using much less gas). Or under monster demand, if the A7 fell behind, the gas could do the whole job.. Running the A7 in a server room sounds great. It will cool the room as it removes the humidity. Get em (new model) while their still in stock.. Power Mizer H2O Heat Pump Water Heater \| eBay __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

05-14-13, 11:20 AM	#273
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	14 days of solar assist http://i46.photobucket.com/albums/f1...psb7b37684.jpg As the weather warms (slightly) we are outdoors more, bike riding more and that's increasing our hot water use by at least 30 percent. With mixed weather, the A7 has been using 0.5 kWh per day off the grid. PV hot water heating helps! __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

05-14-13, 03:13 PM	#275
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Compared to last August, PV is helping.. Not a lot of data with the new dual array setup.. Last August: http://ecorenovator.org/forum/geothe...html#post23840 23 days (or 552 hours) of operation and the A7 has run for almost 38 hours, Using 22.65 kWh. That's almost 1kWh ($00.1633) per day. We were using about 1kW per day, and now it's about half that. This kind of data isn't easy capture, since hot water use is so erratic. Plus, when it's hot and sunny out, we might start using twice as much hotwater, canceling out the solar gains, as we get them! I'm busy enjoying the nice weather, on the bike trail every chance I get. This DIY project is kinda on the back burner unless there are problems.. But, I'm still thinking of using the CAI board and those DC current sensors to measure the PV power during the day and try to save an average wattage. I can use the CAI email feature to shoot out an email each day, and convert the numbers into usable data, somehow.. I think there might be a way to have Excel just read the CAI page during the day and create a plot.. I would have to manually enter the KilaWatt meter kWh number. I'm so retired and this seems so much like work! __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

05-25-13, 09:43 PM	#279
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Pics Side by side.. That top thermostat(T-stat) the one you set with the temperature dial. (It's fed by a skinny copper tube fed into the tank). The two wires are for adding a second thermostat, in parallel with the existing T-stat. If your hot water heater tank has an unused thermostat, you could connect it to the BL & BR wires.. I really don't see the point of the two extra wires.. They aren't needed.. Maybe using a T-stat on the bottom of the tank would make the until work better.?. Attached Thumbnails __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..