A7 AirTap install (ASHP hot water heater) - Page 35

brogsie · 10-02-13, 02:48 PM

My a7 is connected through the cold water inlet witch is at the bottom of my tank. When the coil first hit the other side of the tank it took a little effort to get it to start curling around the tank. After that it went in pretty smoothly. The t stat bulb goes in with the coil so I think mine runs more often because of the cold water washing over the bulb. I always have hot water but maybe not the most economical with the short run times.

brogsie · 10-02-13, 02:56 PM

If I use the power from the circulator pump to run the a7 can I just plug in to that and not use the black wires at all? The unit runs all the time now when powered. Won't the boiler come on also? Would need to disconnect the boiler?

Xringer · 10-02-13, 03:35 PM

Quote:

Originally Posted by brogsie

If I use the power from the circulator pump to run the a7 can I just plug in to that and not use the black wires at all? The unit runs all the time now when powered. Won't the boiler come on also? Would need to disconnect the boiler?

Yeah, that's what we agreed would be the best way..
Run a short heavy duty AC extension cord from the 'new' AC outlet near the circulator pump, over to the A7..

Leave those black wires capped off. And if your A7 T-Stat opens back up,
(runs normally) you can just by pass it, by connecting those two black wires together..
Heck, you might want to do that anyways, just to keep the current from heating up the old A7 T-Stat..

Edit:
If you want to be able to restore your old boiler's circulator pump,
just install a short cable on the pump motor, with a 120v 15A plug on the end.
In case of fall-back, you can just plug it back into, from which it came..

brogsie · 10-02-13, 04:55 PM

Thanks Xringer I wasn't sure if I could leave it running through the a7 t stat. I'm not there so I can't look at it. The boiler must kick on also when the thermostat calls for hot water. I will have to look at it and report back. Thanks again.

Xringer · 10-02-13, 05:50 PM

There might be a jumper to stop the burner from firing..
My upstairs zone coming on will cause oil to burn, (if boiler temp is a little low)
but the downstairs (basement) zone will run and not turn on the burner.
It did cause burns, when the water temp dropped it would fire up anyways.

Or, you might have a main separate switch on the burner power input line..

Xringer · 10-02-13, 05:55 PM

If it looks to hard to use the burner's power, I can build you a SSR switch to power
the A7, using the tank's low voltage T-stat..

I've got some 25A 240vac SSRs on hand..

brogsie · 10-02-13, 06:09 PM

Your the man!
I'm going to look at it Friday.
I'll keep you posted.

brogsie · 10-05-13, 08:33 AM

No switch between my boiler control and the burner. Here's my plan. disconnect circulator and put a 15 amp outlet on that feed. Put plug on the circulator. Put a switch in between the boiler control and the burner.

When using the a7 I will plug into new outlet. Shut off switch between burner and boiler control.

When using boiler for hot water, unplug a7, plug in circulator, turn on switch to burner.

Sound right?

Xringer · 10-05-13, 11:58 AM

Yeah! That allows your hotwater tank to be used by both systems.
Sounds like it should work just fine. And not too costly.

Not much sun around here lately. I hit the X10 button to fire up the A7..
Within a few minutes, the sun started peeking out!

My current project will be to use my CAI controller to turn on the A7 automatically, but only when it's needed.
I'll control the hours and I'll make allowances for sunny days.
The program should be able to detect when the PV is going the job, and not turn on the A7..

I have not decided whether to use a DC current sensor, or just watch
the water temp in the tank. (That sensor is already installed).

If the water temp is increasing, that's a good sign of solar.
This method might not work as expected if we start using a lot of hot water.
That could cause a temp drop and start the A7, even when it's sunny.
But, that could be a good thing, if we are using a lot of hotwater,
both heat sources will speed up recovery time.

Just now the basement Fresh air blower just started up..
The humidity must have dropped low enough to trigger it.

brogsie · 10-05-13, 12:06 PM

I think you had mentioned it earlier but my wife asked me what she's going to do if I die. She won't know how to get hot water. Guess I'll have to make up an instruction manual.

Don't know how you figure out all you are doing. It makes my head spin.

10-02-13, 05:50 PM	#345
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	There might be a jumper to stop the burner from firing.. My upstairs zone coming on will cause oil to burn, (if boiler temp is a little low) but the downstairs (basement) zone will run and not turn on the burner. It did cause burns, when the water temp dropped it would fire up anyways. Or, you might have a main separate switch on the burner power input line.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

10-02-13, 05:55 PM	#346
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	If it looks to hard to use the burner's power, I can build you a SSR switch to power the A7, using the tank's low voltage T-stat.. I've got some 25A 240vac SSRs on hand.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

10-05-13, 11:58 AM	#349
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Yeah! That allows your hotwater tank to be used by both systems. Sounds like it should work just fine. And not too costly. Not much sun around here lately. I hit the X10 button to fire up the A7.. Within a few minutes, the sun started peeking out! My current project will be to use my CAI controller to turn on the A7 automatically, but only when it's needed. I'll control the hours and I'll make allowances for sunny days. The program should be able to detect when the PV is going the job, and not turn on the A7.. I have not decided whether to use a DC current sensor, or just watch the water temp in the tank. (That sensor is already installed). If the water temp is increasing, that's a good sign of solar. This method might not work as expected if we start using a lot of hot water. That could cause a temp drop and start the A7, even when it's sunny. But, that could be a good thing, if we are using a lot of hotwater, both heat sources will speed up recovery time. Just now the basement Fresh air blower just started up.. The humidity must have dropped low enough to trigger it. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

10-02-13, 02:48 PM	#341
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	My a7 is connected through the cold water inlet witch is at the bottom of my tank. When the coil first hit the other side of the tank it took a little effort to get it to start curling around the tank. After that it went in pretty smoothly. The t stat bulb goes in with the coil so I think mine runs more often because of the cold water washing over the bulb. I always have hot water but maybe not the most economical with the short run times.

10-02-13, 02:56 PM	#342
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	If I use the power from the circulator pump to run the a7 can I just plug in to that and not use the black wires at all? The unit runs all the time now when powered. Won't the boiler come on also? Would need to disconnect the boiler?

10-02-13, 04:55 PM	#344
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	Thanks Xringer I wasn't sure if I could leave it running through the a7 t stat. I'm not there so I can't look at it. The boiler must kick on also when the thermostat calls for hot water. I will have to look at it and report back. Thanks again.

10-02-13, 06:09 PM	#347
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	Your the man! I'm going to look at it Friday. I'll keep you posted.

10-05-13, 08:33 AM	#348
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	No switch between my boiler control and the burner. Here's my plan. disconnect circulator and put a 15 amp outlet on that feed. Put plug on the circulator. Put a switch in between the boiler control and the burner. When using the a7 I will plug into new outlet. Shut off switch between burner and boiler control. When using boiler for hot water, unplug a7, plug in circulator, turn on switch to burner. Sound right?

10-05-13, 12:06 PM	#350
brogsie Helper EcoRenovator Join Date: Oct 2013 Location: mass Posts: 51 Thanks: 26 Thanked 3 Times in 2 Posts	I think you had mentioned it earlier but my wife asked me what she's going to do if I die. She won't know how to get hot water. Guess I'll have to make up an instruction manual. Don't know how you figure out all you are doing. It makes my head spin.