Thread: Huge price to replace A/C compressor

Originally Posted by totoblue

We've got ducted reverse cycle air con for heating and cooling. It's got 13 outlets in a house about 200sqm (approx 20squares). Weatherboard, ceiling insulated, but walls and floors are not insulated. Single glazing. Heavy curtains. Location: Melbourne.

It's 3 phase powered and draws about 6kW on cooling cycle.

The tech says the compressor is seized (due to gas leaking out and thus the oil as well) and needs to be replaced. It's an ancient York system and the quoted price for supplying and fitting a replacement including gas etc is $2250, not including anything else that they discover is broken after fitting it.

That seems like a lot to me, particularly as it is just a repair on an old non-inverter system which is presumably more inefficient than a modern one, and presumably other parts of it are worn out as well (it's probably about 30 years old - I've got the brochure and it's copyright 1977)

I presume that the 6kW power draw means it has about 12-18 kw of heating and cooling capacity, depending upon it's efficiency.

I was at Bunnings the other day and they had Mistral reverse cycle aircon units (non inverter) for $475 with about 3KW cooling/heating capacity for 1KW power draw. So about 3 of those would probably be enough (one for the bedroom, one for lounge and one for family room) which would be about $1500 plus installation, possibly totalling the same price (although it probably wouldn't heat or cool the whole house, just 3 rooms). Now I'm not suggesting this is a great brand or the best price - but it's an indication.

Anyone got any comment on this? Is that a reasonable price for the repair of the existing unit? Can a compressor be repaired instead of replaced? Anyone got any recent prices for new ducted R/C air con for a 20 sq house in Melbourne? Or ducted gas heating for that matter?

the suggested work is probably reasonable. Not sure about the price
However, the gas for the existing unit was most likely phased out 10 to 15 years ago. So the price you've been quoted should include the compressor, a regass, new seals (there's a potential corrosion problem with modern gas and old gas seals) I'm not sure there's much else that could have gone wrong.



BTW, you lucky bugger, you've already got 3 phase power so can run decent sized machines.

totoblue,

The price seems reasonable, although obviously its hard for us to tell for sure without seeing the specifics of the job. A few things to keep in mind:

1. Its a 3 phase compressor, these arnt cheap and a fair chunk of the price would be for this.

2. From the age of the system, there is a possibility that the refrigerant used was R12 which is no longer available. Depending on the replacement refrigerant they choose, other parts may need to be replaced to accommodate the new refrigerant.

3. Once again based on the age, the new compressor connections may be slightly different than the original. This would require some re-routing of pipes in the unit which can be fiddly and take a while.(adding to labour costs)

4. The mistral prices you quote are for cheap and nasty units and dont really have much relevance to this topic(regardless of how tempting the price may be).

5. Sometimes the cost of replacing a compressor or instead replacing the entire condensor(outdoor) unit can be within a similar price bracket, so its an option to consider.

I would definetly get a couple more quotes and go from there.

On a unit that old I believe the efficiency is more like 2:1 rather than the 3:1 that is currently being achieved you may be better off to consider the replacement of it rather than repair as it will pay for itself in reduced operating costs

Doug

Thanks for the replies.

Re the gas, I specifically asked the tech about this and he said it was R22 (IIRC) and that it would could be refilled with the same gas. I had been burnt on this for my car's air-con (which had to be regassed with a different gas and then all the seals died - which they warned about - and I had to get a new compressor anyway - total about $1300).

Is it true the air-con gas is very expensive or are they just charging a huge mark-up on it? The mechanic charged a fortune for the gas, compared to say, engine oil.

The quote for the house air-con is not broken down, so I might give them a call.

Seems reasonable to me. Bare air-con & fridge compressors (which are essentially the same thing) are spectacularily expensive things to buy as replacement parts. For example, the little Danfoss units that you find in your average small to medium fridge cost (the last time I looked) about $750 straight from Danfoss........so it doesn't take much imagination to imagine how the compressor to suit a big air-con unit like yours might cost.

Originally Posted by cross

totoblue,


1. Its a 3 phase compressor, these arnt cheap and a fair chunk of the price would be for this.

2. From the age of the system, there is a possibility that the refrigerant used was R12 which is no longer available. Depending on the replacement refrigerant they choose, other parts may need to be replaced to accommodate the new refrigerant.

3. Once again based on the age, the new compressor connections may be slightly different than the original. This would require some re-routing of pipes in the unit which can be fiddly and take a while.(adding to labour costs)

4. The mistral prices you quote are for cheap and nasty units and dont really have much relevance to this topic(regardless of how tempting the price may be).

3 phase compressors are usually cheaper, because they are simpler. but that price is about right. I would actually charge closer to $3k. I know, we are criminals.

R12 was never used in domestic air conditioning, R22 was and still is so no retrofit required. R22 still has a few years left although it is being slowly phased out.

Re running pipes prob no issue, the old york ( a brown boxy unit if it's what I'm thinking of) will still have available parts. pretty sure its either a mitsu' or a TAG compressor.

Nothing wrong with the mistral unit. if installed with a good vac it will last years. A top shelf unit is nothing if the install is second rate.

And from another post, there are no seals to replace, it's a hermetic compressor.

Before you replace the compressor, look at the starting capacitors. These are usually a slightly flattened beer can so that instead of being round it is oval. There will be two wires attached. The important thing is that the sides of the capacitor should be parallel to each other.

If the capacitor looks pregnant, then the capacitor has failed and the compressor won't start. The compressor sounds like it is frozen and refuses to start turning. If the capacitor has failed it is a rather inexpensive repair. On a three phase system there are probably three capacitors, one for each phase.

With the power off, just take the cover off your A/C unit and look without touching. Pregnant capacitors are very obvious.

Here it is a common tactic for the A/C repair people to pad their income by replacing compressors when just replacing a capacitor would solve the problem.

Originally Posted by rrich

If the capacitor looks pregnant, then the capacitor has failed and the compressor won't start. The compressor sounds like it is frozen and refuses to start turning. If the capacitor has failed it is a rather inexpensive repair. On a three phase system there are probably three capacitors, one for each phase.

Unless they taught me wrong in tafe motor theory, there are no capacitors in 3 phase motors.

Capacitors are used in single phase motors to create the initial magnetic field to start to motor turning. In motors where the capactitor is no longer working the motor will normally be stalled but a manual turn of the shaft will get it going. Depending on the type of motor there maybe a centrifugal swich which disconnects the capacitor and start winding in the motor once it has sped up or it may be permanently connected. So the capacitor is basically acting as a hand to give it that initial kick start and spin.

As three phase power has three phases each 120deg out of phase to the other. So when one magnetic field is collapsing there is another building up that the stator(?) in the middle of the motor is attracted to which causes the motor to turn. When this one collapses it moves onto the next and so on and so on.

Originally Posted by null & void

Unless they taught me wrong in tafe motor theory, there are no capacitors in 3 phase motors.

Capacitors are used in single phase motors to create the initial magnetic field to start to motor turning. In motors where the capactitor is no longer working the motor will normally be stalled but a manual turn of the shaft will get it going. Depending on the type of motor there maybe a centrifugal swich which disconnects the capacitor and start winding in the motor once it has sped up or it may be permanently connected. So the capacitor is basically acting as a hand to give it that initial kick start and spin.

As three phase power has three phases each 120deg out of phase to the other. So when one magnetic field is collapsing there is another building up that the stator(?) in the middle of the motor is attracted to which causes the motor to turn. When this one collapses it moves onto the next and so on and so on.

We don't use centrifugal switches in hermetic compressors. Reason being all the electrical windings are exposed to the refrigerant and oil. in the system. If we had a switch inside there would be arcing which will burn the oil.

Basically burnt oil means rapid burnouts of compressors.

True that there are no start caps on 3~ compressors. Only rarely used as power factor correction when running on clean supplies. The big current draw on a stopped rotor when powered up gives plenty of torque (remember an induction motor produces the most torque at stall). instead we use start relays to drop off the start windings except for start caps in series with the windings in some applications.

The start windings create the initial rotating force not the cap. The cap just provides extra torque by keeping voltage up on the downslope of the sine wave keeping that extra bit of current to get it moving.

Totoblue, did the quote include installation of a burnout drier? for $2250 i'd assume not, if you have a burnt out compressor the oil will be contaminated and you'll be up for a new compressor in the next year or so.

To be honest i'd look at replacing the unit and reusing most of the existing ductwork.

Originally Posted by Timmo

Totoblue, did the quote include installation of a burnout drier? for $2250 i'd assume not, if you have a burnt out compressor the oil will be contaminated and you'll be up for a new compressor in the next year or so.

Is there a typo above? Or are you saying that without a burnout drier, the new compressor will last only a year or so?

The quote says:
Included: labour, compressor, refrigerant gas, oxy+acet+solder, vac pump
Excluded: any parts found faulty after new compressor fitted

So it sounds like no burnout drier. A sight glass or some other way of checking the gas level would seem useful to me as well.

Timmo, would you suggest the burn-out drier as a permanent fitting or just temporary until the any contamination (acid etc) is removed? Some of the material on the net suggests that it's removed after once the contamination is removed (e.g. http://www.airah.org.au/downloads/2004-04-F02.pdf)

BTW for other readers - I googled for "burnout drier". It's a filter that cleans the a/c gas of acid and water etc. See above link.

Originally Posted by Timmo

To be honest i'd look at replacing the unit and reusing most of the existing ductwork.

We're looking to sell soon. If we were staying, I think I'd look into getting a new inverter RC A/C system possibly combined with gas ducted or gas space heaters.

The comparison with R/C vs Gas ducted is problematical, but seeing you already have RC, it's probably cheaper to maintain it than to replace it from an embedded energy point of view. Maybe you can keep the existing ductwork and drop in a high efficiency unit...

Looking forward, there are benefits to be had in energy use by paying attention to the way the heating is used (temperature and hours of use), and also the heat losses in the house. We're grappling with this at the moment, our house is an older stone affair and the losses out the windows and walls are where we are focussed presently...

woodbe.

Originally Posted by null & void

Unless they taught me wrong in tafe motor theory, there are no capacitors in 3 phase motors.

Interesting! I was not aware of that. Generally speaking, here three phase power is used for commercial and industrial applications. Single (some here call it dual) phase is what is commonly delivered for residential use.

Originally Posted by totoblue

Is there a typo above? Or are you saying that without a burnout drier, the new compressor will last only a year or so?

The quote says:
Included: labour, compressor, refrigerant gas, oxy+acet+solder, vac pump
Excluded: any parts found faulty after new compressor fitted

So it sounds like no burnout drier. A sight glass or some other way of checking the gas level would seem useful to me as well.

Timmo, would you suggest the burn-out drier as a permanent fitting or just temporary until the any contamination (acid etc) is removed? Some of the material on the net suggests that it's removed after once the contamination is removed (e.g. http://www.airah.org.au/downloads/2004-04-F02.pdf)

BTW for other readers - I googled for "burnout drier". It's a filter that cleans the a/c gas of acid and water etc. See above link.



We're looking to sell soon. If we were staying, I think I'd look into getting a new inverter RC A/C system possibly combined with gas ducted or gas space heaters.

No Typo, depends how bad the system is. If it's been running short on charge (gas) for any length of time the compressor (and gas) runs very hot. The critical temp for r22 is just 99 deg C. Basically it means that at this temp it changes state from a vapour to a gas and will start to break down as well as cooking the oil. From here we start getting a buildup of acid in the system and regular burnouts in compressors.

This problem is accelerated when there is moisture in the system especially with newer refrigerants that need synthetic oils such as R410a, R407c and R134a in fridges as the synthetic oils absorb moisture.

There are a couple of ways to use a burnout drier. You can have a large capacity one soldered permanently in or a smaller capacity one with a removable core that can be either changed or removed when the system is clean. There are service ports on either side so we can measure the pressure drop across it as it loads up.

For your unit I'd look at a large capacity suction line drier if room permits or a liquid line jobby. being the first burnout It shouldn't be too hard to clean up.

There are acid test kits available to tell the condition of a refrigeration system. If you ask the fridgey for a quote to add the drier it'll probably cost an extra $200 but will be money well spent IMO.

That said if you're looking at selling then just omit the drier and pass the problem on. the old York has had a pretty good run.

Originally Posted by Timmo

There are a couple of ways to use a burnout drier. You can have a large capacity one soldered permanently in or a smaller capacity one with a removable core that can be either changed or removed when the system is clean. There are service ports on either side so we can measure the pressure drop across it as it loads up.

For your unit I'd look at a large capacity suction line drier if room permits or a liquid line jobby. being the first burnout It shouldn't be too hard to clean up.

...If you ask the fridgey for a quote to add the drier it'll probably cost an extra $200 but will be money well spent IMO.

That said if you're looking at selling then just omit the drier and pass the problem on. the old York has had a pretty good run.

I spoke to the company and they said it didn't need a new drier as it didn't burn out, it seized due to lack of oil because the gas leaked out. Seizing presumably doesn't contaminate the system.

I also removed the cover from the outdoor unit and it already has an EK-053S drier already fitted, which is soldered in and doesn't seem to have replaceable anything. According to the net, it is a loose bead type, and is about $20-40 USD (or $49 in AUD). It doesn't look like it is a large capacity drier to layman me (see pic - it's not very big, and there are no ports to measure the pressure drop either).

http://www.flickr.com/photos/totoblu...7600545952409/

The suction accumulator is a bit rusty too - don't know if that is a problem but it could be a potential leak.

The compressor is a YHE6-0500-TFDC Copeland. Seems to be about $600-800 USD on the net.

I asked about replacing the whole thing and they said about $7-8000 for a similar sized Mitsubishi ducted inverter system, which would save about 25-30% on electricity.

They did come up with another idea which is to replace just the outdoor unit. York can supply replacement outdoor units that are compatible with old systems like mine. Provided the price is reasonable, that sounds like a good idea for resale. Might get a new thermostat fitted at the same time and it'll look like a whole new air-con system (and it will be, almost).