PDA

View Full Version : Heater/cooler split system A/C electrical connections help pls!







JamesQB
22-06-2005, 12:19 AM
Hi everyone,

My parents bought a weird-named split-system air conditioner (indoor blower and outdoor compressor unit) and since they're not too wealthy at present, I offered to fit it (I'm an electronics engineer but with a fair general knowledge).

There's a Hitachi sticker inside, so maybe they really made it.

I've done all the pipework, blown out the air and pressurised the lot. Now ready to do the electrical connections. Other units here are cool air only with just live and neutral connections on the indoor and outdoor units for the interconnecting cable. This one's got four connection points in each unit.

The problem is that despite looking in the outdoor unit with covers completely off and having done voltage checks on the indoor unit whilst running in the the different modes, I cannot work out what should be happening and so cannot connect up the two separate units.

The indoor unit connector block has one constant neutral and three switched lives. On 'cold' setting, two lives appear. On 'heat' setting, the last live appears and the other two disappear. The permanent neutral has a blue wire in the block, and the lives have a brown, a pink, and a black. Brown and pink active on cold, only black active on heat (as far as I can tell).

Inside the outside unit, the four wires are marked A B C D (indoor unit has 1 2 3 4) in the connector block. The wire colours are red, blue and two black. One black is slightly thinner than the other wires.

Here's a diagram. Hollow rectangle-type thing going from cap to compressor is a white wire.

http://www.spiritworldcentral.com/images/other/conditioner.jpg

If I ignore colour codes, it'd seem that red is neutral and the others each turn on either the fan, compressor, or valve, whichever it wants on at any given time by supplying the voltage on one of the 3 switchable lives inside the indoor unit. So that may be right, but why the third wires (white and yellow) coming from the fan and compressor to the capacitor? The main wires (black and thin black) could go straight to the cap and onwards to feed each item, surely? Or is this standard for this type of equipment? Would the two wires (live feed and one going to the cap) just be connected to each other inside the units they go into?

After understanding why three wires go into the compressor and fan, the next main problem is, even if I know what is going on inside the outdoor unit, how do I know which of the two lives which come on when the air conditioner is set to 'cool' feed the fan and compressor respectively, since inside the indoor unit the same gauge wire seems to be used for both lives which come on when 'cool' is selected, unlike the different gauge wires used in the outdoor unit? Assuming, that is, that the two lives which come on do indeed feed the fan and compressor, but that seems a logical assumption since the valve is responsible for reversing the flow for when 'heat' is selected and therefore takes care of the third live which comes on when heat is selected, whilst the other two turn off.

Does anyone know which of the two lives which come on for cold air go to which part in the outdoor unit, or does anyone know how to find out?

Incidentally, no documentation came with the kit except for operating instructions but no electrical diagrams.

Many thanks for any help.
James

wambat
22-06-2005, 06:33 AM
Heres’s what I believe you have:
1. There is power available at the blue terminal at all times when the manual switch at the thermostat is set for heating. If the reversing valve is wired to “B” then the RV solenoid will be energized at all times
2. Red is the common neutral
3. Both the compressor and the fan are permanent split capacity motors. Therefor require their own capacitors such as is shown in your diagram thus the extra white and yellow wire.
4. The large black is the hot leg to the compressor and the small black is the hot leg to the fan, all come back on the red neutral
I hope this makes sense for you

chemi-cool
22-06-2005, 02:33 PM
I'll make it simple for you to check,
Connect an extension cable from the house with the wire ends, open, connect the blue to the natural, then touch with the live end each one of the other wires and simply see what component starts to work.
There are only three, compressor, fan, and 4 way valve coil.
once you know which is which, mark it down.

connect the two units and watch if it runs OK.
Do not forget to ground it.

good luck

Chemi :)

frank
22-06-2005, 07:23 PM
documentation came with the kit except for operating instructions but no electrical diagrams.

You would normally see a wiring diagram on the inside of the electrical cover.

So that may be right, but why the third wires (white and yellow) coming from the fan and compressor to the capacitor? The main wires (black and thin black) could go straight to the cap and onwards to feed each item, surely? Or is this standard for this type of equipment? Would the two wires (live feed and one going to the cap) just be connected to each other inside the units they go into?

As the unit is single phase, these wires connect to the start or run windings. Every single phase motor has more than one winding. The capacitor "shifts" the phase of a winding to create a circular motion.

frank
22-06-2005, 07:25 PM
I'll make it simple for you to check,
Connect an extension cable from the house with the wire ends, open, connect the blue to the natural, then touch with the live end each one of the other wires and simply see what component starts to work.
There are only three, compressor, fan, and 4 way valve coil.
once you know which is which, mark it down.

connect the two units and watch if it runs OK.
Do not forget to ground it.

good luck

Chemi :)
Geeze Chemi - and electronics guy with live 240v wires :eek:

chemi-cool
22-06-2005, 07:41 PM
He should be wearing snickers and stand on a dry cardboard.
Didn't I mention it? :D

Chemi :)