First Heatpump project

[stef110]

The default position of the valve is, to cool the HX, but i want to heat my HX.
The whole idea is to heat the house i will never use the cooling function probably only on defrost if necessary.
But i assume i cant change the valve, because it is inside the unit what was pre-charged with gas.

In my case i can just power the valve when compressor starts and shut off at the same time? is it also possible to change the valve while compressor is running? like in a sudden defrost action? of should you first turn of the compressor?

stef

[AC_Hacker]

Originally Posted by stef110

The default position of the valve is, to cool the HX, but i want to heat my HX.
The whole idea is to heat the house i will never use the cooling function probably only on defrost if necessary.
But i assume i cant change the valve, because it is inside the unit what was pre-charged with gas.

In my case i can just power the valve when compressor starts and shut off at the same time? is it also possible to change the valve while compressor is running? like in a sudden defrost action? of should you first turn of the compressor?

stef

Good question about when. My guess is that the 4-way can be changed anytime.

Let's hear it from some others.

-AC

[stef110]

Just did my first bench test:





DT = 20 degrees
Mass = 100 liters
C = 4180J
PW = 0,528 kWh of used electricity

Q = M * C * DT = 100 * 4180 * 20 = 8360000 joule
E = 3600000 * 0,528 = 1900800 joule
COP= 4,398

http://www.youtube.com/watch?v=L6RfIUUhgLs

stef

[stef110]

Maybe tomorrow I will install the heat exchanger inside the house.
From what i know and how i hooked everything up now,
The hot gas flows from the top of the hx to the bottem right?
And the water on the other will flow from the bottom to the top right?

I need also need to get my r410a back in to the outdoor unit.
From what i read you close the gas service valve, turn on the compressor and wait till the gauge on the manifault go in to the vacuum area. Then you close the liquid line, and right after that you turn of the compressor. Is this the correct way?

stef

[AC_Hacker]

Originally Posted by stef110

Maybe tomorrow I will install the heat exchanger inside the house.
From what i know and how i hooked everything up now,
The hot gas flows from the top of the hx to the bottem right?
And the water on the other will flow from the bottom to the top right?

Yes, you have it right. You want gravity to assist you with regard to gas, and you want the water to flow opposite to the gas flow, you have it right.

Originally Posted by stef110

I need also need to get my r410a back in to the outdoor unit. From what i read you close the gas service valve, turn on the compressor and wait till the gauge on the manifault go in to the vacuum area. Then you close the liquid line, and right after that you turn of the compressor. Is this the correct way?

I think that is correct, but so far I have not done that operation myself, so you should wait for experienced advice on that question.

-AC

[jeff5may]

Originally Posted by stef110

The default position of the valve is, to cool the HX, but i want to heat my HX.
The whole idea is to heat the house i will never use the cooling function probably only on defrost if necessary.
But i assume i cant change the valve, because it is inside the unit what was pre-charged with gas.

In my case i can just power the valve when compressor starts and shut off at the same time? is it also possible to change the valve while compressor is running? like in a sudden defrost action? of should you first turn of the compressor?

stef

The reversing valve has its own wire on the thermostat. When your thermostat isn't in the "off" position, the wire is active. Since your outdoor unit is in cooling mode at rest, the thermostat will keep the reversing valve solenoid energized the whole time it is in heating mode, whether or not the unit is actually heating. This practice saves wear and tear on the moving parts of the reversing valve. It also serves to power the defrost control module (if equipped) during heating mode.

The only time the reversing valve should not be energized in heating mode is during defrost. The wire from the thermostat will remain active throughout heating mode, regardless of whether the unit is defrosting or not. The defrost control circuit will spool the reversing valve (and control other devices in the outdoor unit) when it needs to. It operates on its own schedule, and there are many different kinds of defrost controls, some smarter than others.

You don't want to tie the reversing valve to the compressor control circuits. Lets say you've been heating for awhile, and the thermostat is satisfied. If the reversing valve spools back to cooling mode when the compressor isn't running, the high pressure liquid in the condenser will flow backwards through the valve and straight into the compressor. It will push its way through the crankcase, foaming up the oil and carrying some of it into the cylinder or scroll . The gas then flows through the compressor exhaust valve, finding the low pressure it has been seeking.

When the compressor is running, it can quickly spit out the oil carried in with the refrigerant. If you listen to the outdoor unit when it enters or leaves defrost mode, you can hear the distinctive "whoosh" sound as this happens. When the compressor is still, the scroll or cylinder tends to trap the oil inside it. When the compressor starts up on the next cycle, the trapped oil has to be pushed out all at once, hammering your cylinder or scroll hard as it squeezes through the exhaust valve. This is not good.

[NiHaoMike]

To pump it down, first close the liquid line valve, run the compressor until the suction side starts to go into a vacuum, then close the suction valve. (If there's a low pressure control, you'll have to bypass it.) Then backfill with nitrogen before opening the system, after which you tape over or cap the open ends until you're ready to put it back together.

[stef110]

Thanks for the info, today I pumped down the system en removed the HX.
I also hooked the HX up to the central heating system.









Today I also placed the electronics in a nice box.

[stef110]

Today i created the circuit board for the outdoor unit, his job is to read values from 5 one-wire temperature sensors and spit them out by the rs485 bus.
It also has a push button, that i can use to turn the system on, when i am outside for testing purpose. At the moment I am really busy with coding.



stef

[jeff5may]

Awesome, totally awesome! You must own a pipe bender, because I see a whole lot of custom-bent pipes. Very nice.