Any air con engineers on here?

[flanajb]

Just purchased my split air con unit and the company I purchased it from on ebay state the system is pre gassed and does not require a vac pump. Well, the system has arrived and after unboxing it I see a 3m length of copper pipe that needs to be connected to both the outdoor and indoor unit. This to me means it is not pre gassed as when I connect it all up there will be air in the 3m pipe.

The outdoor unit has a vac pump connection point and the instructions make mention of attaching a vac pump.

The item I purchased is here

http://www.ebay.co.uk/itm/BERGDORF-24K- ... 3d00197ce3

Thankfully, I do have a vac pump so I can purge the system of air before opening the refrigerant gas valve, but I think the company here are very misleading. They are basically advertising a unit as an easy install for Joe Bloggs, but in all reality they are just cutting corners. I think it's a bit naughty.

Open to comments if I am mistaken and you do not need to connect a vac pump.

 

[clk230]

I would setup as they tell you if it doesn't work then contact them , I'm sure they must have tested the systems they sell.

 

[flanajb]

I would setup as they tell you if it doesn't work then contact them , I'm sure they must have tested the systems they sell.

On reflection, I am going to call the seller. From what I have read on the interweb, failure to purge the system of air will result in reduced equipment life and sub optimal operation.

 

[jimmy_s]

Well I used to be a refrigeration engineer so hope this helps.

Short of purging the air from the hoses before connecting you would have problems I would think. Any air in the system will increase the condensing pressure and running costs (Daltons' Law of partial pressures). I don't know what refrigerant is in the split but chances are it would be illegal to purge the pipes and you may end up with an undercharged unit. Purging would normally involve purging using vapour phase refrigerant but most of the modern refrigerants are mixtures that often don't behave as true azeotropes, therefore if you purge with gas you alter the blend as the gas phase does not contain equal percentages of each refrigerant. The other problem with air in the lines is probably be moisture present. As a result you end up with some moisture in the system. Moisture tends to be a problem as it can block the expansion valve and also can over time result in the refrigerant breaking down.

If you have a vac pump it would be better to vac out the lines.

Jimmy

 

[flanajb]

Well I used to be a refrigeration engineer so hope this helps.

Short of purging the air from the hoses before connecting you would have problems I would think. Any air in the system will increase the condensing pressure and running costs (Daltons' Law of partial pressures). I don't know what refrigerant is in the split but chances are it would be illegal to purge the pipes and you may end up with an undercharged unit. Purging would normally involve purging using vapour phase refrigerant but most of the modern refrigerants are mixtures that often don't behave as true azeotropes, therefore if you purge with gas you alter the blend as the gas phase does not contain equal percentages of each refrigerant. The other problem with air in the lines is probably be moisture present. As a result you end up with some moisture in the system. Moisture tends to be a problem as it can block the expansion valve and also can over time result in the refrigerant breaking down.

If you have a vac pump it would be better to vac out the lines.

Jimmy

Thanks Jimmy, on reflection I am going to return the unit to the seller. Under the sales of goods act I have basically been miss sold a product and I find that very annoying. Already spoke with the credit card company who have said that if the seller does not take the item back they will raise a dispute.

:evil: