Thread: Reducing cost of split system Air Con install

Originally Posted by Fat Pat

Wildman, I had a mate instal 2 units at my place, with me providing "Gofer" duties, here are my thoughts on the matter....

1. Read the instruction manual that comes with the unit, it should give you the size of the pipes required. Remember that there are two sizes, one for the "Go" gas, and one for the "Return". If you get the flexible copper pipe, it is pretty simple to route it as you want, the rigid stuff will require gas burner and bending tools. Plus you need pipe flaring tools for the joins etc.

2. You will need pipe insulation to suit the lengths you require.

3. Depending upon power requirements all you may need is a power point adjacent to the head unit (and a single 3-core run to the external unit) or the more complicated (and expensive) fixed install with isolation switch to the external unit. If it is the simple set-up, then anyone can run the power cable, as long as a "Licensed" person does the connections.

4. The instruction manual will give pipe-length guidelines, if you have a longer "throw" then you may need to top-up extra refridgerent, as there may not be sufficient pressure to maintain cooling. Plus a longer run will result in the compressor having to use more of its power to push the gas - leaving less for actual cooling. My 1 HP unit has a 7 metre run each way, and my 3.5 HP unit has about 15 metres in each direction - neither unit has any trouble keeping the place cool (in fact I generally have 10-15 degrees in excess cooling capacity)

5. You can mount the compressor from a rack on a wall, but I don't recommend it, as you can get some funny vibratory type noises coming through the house. Placing the unit a couple of concrete slabs or brick paving is more than adequate. GENERALLY, the units are extremely quiet, much quieter than an equivalent RAC (Box-in-Wall Type)

6. Don't forget the drip pipe. MY 3.5 HP unit throws up to 3 litres of water an hour. so if you don't want your brick paving to turn green, then you'll need to install a proper drain.

A final thought to consider. In Perth (and presumably OZ generally) we have seen stacks of "No-Name" A/C splits advertised for bargain prices. Their problem is that they have very inefficient compressors, so you need to use a lot more power than "Brand Name" units. They may have a 5-Year warranty, but if you use 5 times as much powere, are they really that good a deal.

I recommend Mitsubishi, and I have no affiliation with them. My units work bloody good, and that is all that matters.

Hope that may help you a bit.

Pls let me know which pipe is the "go" , is it the bigger one ? in my installation manual they call them " gas" and "liqid" pipe so pls explain for me.

3.5hp Airwell system installed for $650 that I bought from Harvey Norman, I was thinking of doing just what you guys are mentioning about doing most of it yourselves. Thank god I didnt because a month after it went in I had to get the whole unit replaced because of faulty pipes in the head unit. If I had of done it myself I wouldnt have been covered by warranty because it must be installed by a qualified installer.

Originally Posted by jolybean

Pls let me know which pipe is the "go" , is it the bigger one ? in my installation manual they call them " gas" and "liqid" pipe so pls explain for me.

In A/C systems on cars, the liquid pipe is always the smaller pipe (compressed gas as a liquid to the TX valve), whilst the gas return pipe (liquid back to gas from evaporator) is the larger pipe. In recent made vehicles they quite often use the same diameter hard piping for both, probably to save the few cents in manufacture.

But then again if you have to ask which is which, then your understanding of this complex piece of machinery may not be sufficient to do the install. Maybe you should get it installed by a professional.

Originally Posted by Dan_574

3.5hp Airwell system installed for $650 that I bought from Harvey Norman, I was thinking of doing just what you guys are mentioning about doing most of it yourselves. Thank god I didnt because a month after it went in I had to get the whole unit replaced because of faulty pipes in the head unit. If I had of done it myself I wouldnt have been covered by warranty because it must be installed by a qualified installer.

Dan,

Read the posts above mate - I have my warranty card signed so mine has been installed by a professional. Just because I did the grunt work myself doesn't make ANY difference i.e. Mount the inside and outside units run the pipes and wiring and have it finished off by a fridgie and sparky.
Read the whole thread before you have a bit of a sledge

Faulty pipes in the head unit ususally mean old mate the installer has overtightened them and caused the fixed copper pipe in the head unit to fail.

Tom

hey tcns I cant see where Im having a sledge, far from it just making people aware of the dangers of not getting it done properly, if yours was signed off well and good.

Just had one 3.5 and two 1HP units installed. Done for $360 each, I'm told the standard price would have been $500 each. Reduction due to electrics; already had a 32 amp circuit in place for the big fella (replacing a weatherwall unit), and 'conveniently located GPO's' on a standard 16 amp circuit for the two 1HP's. Suspect that it might cause some grief if both the 1HP's were started up at the same time, but once running they live happily enough on the same circuit.

Could have saved more by mounting the internal units. Just read the manual and make sure you have the clearances around the unit, and locate it so that it's in (vertical) line with the 'desired' location of the external unit. If you do it yourself you can spend some time thinking about where the vents will blow. To mount the internal unit you (generally) drill a steel plate to the wall (five or six light duty plugs seem to do ok). Then you need a hole through the wall. The manual will indicate where (generally you get a choice of left or right). My guy just buzzed a circle of 6 or 7 holes through with a 15mm or so masonry drill, and then hammered out the waste. Did the inside first, then the outside (double brick) working back in. A bit of thought should ensure the holes line up (dipping slightly towards the exterior, say 10mm). I could easily have done as good (in fact better) job than the air con guy. It looked like his least favourite part of the job.

Pull the unit back off the wall (leave the wall plate) and at that point call in the air conditioning guy. If he's dubious (or if you're dubious) about the quality of the work, tell him that there used to be a unit in the same location (but clear up the brick rubble before he arrives). He probably knows that you know that he knows it's a 'bodgy job', but everyone saves face. Ultimately the hole was about 60mm diameter. Should be large enough to take the pipe 'cluster' that's fitted to the back of the internal unit. Theoretically the hole through the wall should be sleeved, but I didn't see this done.

In WA any further work (eg pipework) would be running close to the wind in terms of regulation, they've got a bit more antsy with airconditioning gas issue. For the amount of work involved in pipe bending and flaring (I've got the tools) I figured paying $280-$300 each would be worth the air conditioning guys time (and mine) - given that I'd still have to get him to come in and do the pressure testing and sign the chit.

In the end my guy charged $20 for nearly a metre of extra vertical piping on each machine. Assuming that you pick the units up from the shop, doesn't hurt to put them where they need to go (internal and external units). Easier for him than manouvering them around your house. Not something that he'd bill you for, but something that puts him in a good frame of mind when he's contemplating a reduction on something else. Last thing - since it's nearly always a blistering hot day when you've got him coming in, rig up a bit of shade over the area where he's working outside - if you can without it getting in the way of ladders. For my guy it was an all day job.

Just my 2c worth..

I bought the unit at cost through my mate who works for Daikin. He also installed it with my help. (only charged for materials for the install. Concrete slabs, copper pipe, ducting etc.)

The whole install was fairly easy, after seeing how it was done. First mount the plate for the indoor unit, put a hole saw through the plasterboard for the pipework and cables then hammer drill out half a brick slightly lower than the inside hole. Next run a new 20A circuit from the meter board above the ceiling down the wall and out the hole in the bricks for the outdoor unit then the interconnecting power and communication cable to the indoor unit. Next mount the indoor unit to the base plate, making sure all 3 pipes pass through the hole in the bricks (liquid small, gas-big, and drain.

Next set the outdoor unit on the slabs and level it. Then connect the pipe work from the units. **Note my mate told me that the R410a gas runs at a higher pressure than R22 and so needs special copper pipe.

Next vac out the system for 20min or so. Do the electrical connections and putting the pipework and cables in ducting whilst waiting for the vac. I didnt know before hand but my unit came pre-charged with enough gas for a certain max length of copper run. So all there was left to do was make sure the system had held vacuume for some time (no leaks) then remove the vac pump and let the gas into the pipework through the service ports.

Next the exiting bit. Turn on the breaker and get the missus to hit the on button on the unit so we can enjoy the sound of an inverter compressor starting up. (quite nice really, if you are into that type of thing....)

All that was left to do was some cleaning up.

Now my point is this. I think the actual install was quite easy. If I did one again I would definately do the same and employ/con a fridgie mate to flare and connect the copper and vac out and charge the system. All my fridgie mates swear by vacuuming out the system first. Also by the time you buy flaring tools and do some practice flares it is probably just as cheap to have someone do them.

Hope that helps someone. Any questions feel free to ask.

Hi I am an electrician and refrigeration mechanic....just reading through these posts and sure i can respect that most people want to do things as cheap as possible but by not using licenced tradespeople for this kind of work you are breaking the law. Electrical work on fixed wiring of any kind and refrigerant work require "Licences" and to perform this work without one is an offence.

Remember if you have a fire in your house or an accident of any kind due to any of this work you will "NOT" be insured..... that extra few hundred bucks soon becomes worth it... so for all you guys using a tradesmen good luck, all you who dont think twice about the long term out comes first insurance warrantys etc.

I am a licensed fridgy, quite happy to sign of self installs if they are installed properly. This is not illegal. However, conditions, are

1) Install is done well, indoor unit/outdoor unit is level and correct clearances to walls, refer to installation manual for these, simple really.
2) Correct copper used for gas type, I am finding many of the cheaper types are coming with the copper pipe supplied. The cheaper units seem to work fine. I have one at home and love it. Simple really.
3) Only I flair the copper, I will bend the copper as this must be done correctly with the correct tools, and you need to make oil traps sometimes and sometimes not, depending on install. Most back to back systems are quite simple.
4) I weld the copper joins if required as you have to use the correct silver content rods depending on the type and run dry nitrogen throught the pipes in order to comply.
5) I vac the unit and check for leaks, as I have the latest tools, including leak detectors, and gauges.
6) I put more gas if needed due to extended runs. Although rare on installs. You pay for the extra gas, fair enough.

Price = $120-$140 depending on location. This buys 1-2 hours of my time. I'm in Preston, Vic,close to Melbourne CBD and do these on weekends or weekday evenings. Call me on 0417 209 552 or email me. Always happy to help a DIY person (me being one). Will do full installs as well and teach you for next time.

Kompsj, welcome to the forum and thanks for your offer. Its good to see tradies who are open to the DIY spirit.

Cheers
Pulse