Diy 12,000btu Air Conditioning

[briansmad]

Hello, I have fitted 12,000BTU AIR CONDITIONING unit bought from ebay. These systems are made in the Far East using Japanese Technology. The compressors used are made by Hitachi and have a five year warranty, the complete system has 12 month RTB warranty. I have fitted it and is working fine, The only thing is i had to bleed the system, I had no tools to use, i.e vacum pump, pressure gauges etc. I do not know if i have enough or to much refridgerent in the system. Should this be checked by a qualified engineer? Can i buy a small container of R407c and gauges to DIY? Thanks.:eek:

[Brian_UK]

Hi Brian, welcome.

Your second question first, yes you can buy refrigerant and gauges over the counter, the UK is still somewhat lax regarding this sort of thing. The smallest container is probably around 7kg and will cost you.

With regard to 'bleeding' some gas, be aware that you have broken the law with respect to releasing refrigerant into the atmosphere.

The problem being that unless you know what you are doing when 'topping' up the charge you could cause damage to the system.

R407C is a little tricky compared with some other gases. The fact you have released 'gas' means that you have corrupted the quality of the refrigerant. What needs to be done now is the whole charge should be recovered from the equipment, transferred to a waste disposal firm (along with your waste disposal licence number) and the system evacuated. The correct charge then needs to be weighed in.

Life gets complicated doesn't it ;)

[briansmad]

Any idea on a price for someone to come and sort it out for me in county durham.

[slingblade]

Ill do it for £2000.

[Andy]

Hello, I have fitted 12,000BTU AIR CONDITIONING unit bought from ebay. These systems are made in the Far East using Japanese Technology. The compressors used are made by Hitachi and have a five year warranty, the complete system has 12 month RTB warranty. I have fitted it and is working fine, The only thing is i had to bleed the system, I had no tools to use, i.e vacum pump, pressure gauges etc. I do not know if i have enough or to much refridgerent in the system. Should this be checked by a qualified engineer? Can i buy a small container of R407c and gauges to DIY? Thanks.:eek:

Hi briansmad:)

er what can I say, no vacumn no warranty, either on the unit or the compressor:)

If it's doing the job leave it alone:(

Purging is a thing of the past, what with enviromental concerns and with this type of refrigerant being a mix not a blend you have only blew off a proportion of one of the gases. (it was never good practice anyway)
Either you have blew of a lot of gas and the unit has a funny mix in it and a low charge, or you have blew off a little gas and the thing has gas and air floating about in it, which will lead to an acid build up and ultimate distruction of the compressor (don't even think about the warranty, they will know if there has been moisture present).

Probably cheaper to buy a new unit than pay for new gas, labour and destruction of the old refrigerant;)
You will have to recover the old gas anyway matter what you do, if you knowingly release it to the air you are breaking the law:(

Why in earth did you not do the thing right and have the pipework vacumned out:confused:

Kind Regards Andy:)

[briansmad]

I think i have blew off alot of gas not sure how much 30 seconds worth maybe 60 seconds max But the air came out fist so 45 seconds max of gas, so i do not think there would be any air left, Any one got any Refridgerant and gauges for sale, I will buy them and top it up to the correct amont? Thanks Brian.

[Andy]

I think i have blew off alot of gas not sure how much 30 seconds worth maybe 60 seconds max But the air came out fist so 45 seconds max of gas, so i do not think there would be any air left, Any one got any Refridgerant and gauges for sale, I will buy them and top it up to the correct amont? Thanks Brian.

Brian your gas is no good, you have blew off only one element of the mix.

Kind Regards Andy:)

[DEVIL]

Andy is right u don't have the refrigerent mix in the right proportions, and even 10 seconds whould had been to mutch, but 60 it's shore that u have less than half of the refrigerent inside and a funny mix, u should call a service personal that knows air conditioning, and they know how to repair it, it's not a easy job as it may look

[breadtrk]

Yes, you MUST evacuate the system down to the micron level. Fact of the matter is that you simply are not qualified to do this. It is your money, do what you want. I promise you will regret not using the phone book to find and hire a professional, if it is not too late. If this has been running very long it is already too late, the damage has already begun and is not reversible.

[mick2me]

Yes, you MUST evacuate the system down to the micron level. Fact of the matter is that you simply are not qualified to do this. It is your money, do what you want. I promise you will regret not using the phone book to find and hire a professional, if it is not too late. If this has been running very long it is already too late, the damage has already begun and is not reversible.

Would have been cheaper to buy a Vac pump?

But what is a good pump to buy for the DIYer who is only likely to need it on one or two occasions?

Does it have to be a two stage pump?

Obviously vaccing down a newly installed system does not entail releasing any gas into the atmosphere? or am I wrong here?

[Brian_UK]

Obviously vaccing down a newly installed system does not entail releasing any gas into the atmosphere? or am I wrong here?Nope, you're right. You would only be vaccing out the normal atmosphere or nitrogen/air mix that was in the newly installed pipes and the indoor unit.

[mick2me]

Nope, you're right. You would only be vaccing out the normal atmosphere or nitrogen/air mix that was in the newly installed pipes and the indoor unit.

Can you confirm the reason for nitrogen?
Brazing joints?

[Brian_UK]

Can you confirm the reason for nitrogen?
Brazing joints?Yep, you're getting good at this Mick:D Also for pressure/strength testing.

[mick2me]

Yep, you're getting good at this Mick:D Also for pressure/strength testing.

:) Not quite... beats me how you keep the nitrogen in the pipes if they are not brazed?

I remember the Fridge engineers I used to work with using it, but my bit was the 'Ranco' (do they still use those?), so I did not pay much attention,
I wish I had now http://www.nottstalgia.com/forums/html/emoticons/flyswat.gif

I take it you dont need the nitrogen for assisting in vaccing down a new system, or do you?

[Brian_UK]

Mick, you bleed nitrogen at low pressure, 2-5psi, through the pipes that you are brazing. It stops any oxides being formed on the inside of the pipework due to the heat/flame contact.

If the oxides are allowed into the system they will block small orifices, capillaries, etc.

It will also damage the oil and eventually the compressor itself.

Once the joints are brazed and all of the flared connections have been made off then you can perform a pressure test. This will prove/disprove the quality of the pipe joints/connections. Any leaks should show themselves under this test.

A strength test means raising the pressure to a set level, say 1.5 times, the maximum working pressure. Not always done by a lot of people however.

Nitrogen can also be used in the evacuation process if you are doing a triple evac.

See also this thread from earlier.
http://www.refrigeration-engineer.com/forums/showthread.php?t=2765

I always have to chuckle at people who are scared of a vacuum test because of the possibility of a leak. Yes it can happen but when you consider that they have just had the system under some 300+psig for some time quite happily that the though of testing at 14.7psig (one atmoshere) makes them go all wobbly ;)

[mick2me]

Mick, you bleed nitrogen at low pressure, 2-5psi, through the pipes that you are brazing. It stops any oxides being formed on the inside of the pipework due to the heat/flame contact.

If the oxides are allowed into the system they will block small orifices, capillaries, etc.

It will also damage the oil and eventually the compressor itself.

Once the joints are brazed and all of the flared connections have been made off then you can perform a pressure test. This will prove/disprove the quality of the pipe joints/connections. Any leaks should show themselves under this test.

A strength test means raising the pressure to a set level, say 1.5 times, the maximum working pressure. Not always done by a lot of people however.

Nitrogen can also be used in the evacuation process if you are doing a triple evac.

See also this thread from earlier.
http://www.refrigeration-engineer.com/forums/showthread.php?t=2765

I always have to chuckle at people who are scared of a vacuum test because of the possibility of a leak. Yes it can happen but when you consider that they have just had the system under some 300+psig for some time quite happily that the though of testing at 14.7psig (one atmoshere) makes them go all wobbly ;)

Thanks for comprehensive reply there.

I read somewhere that minimum period for vaccing down was 1 hour, followed by 1 hour monitoring for pressure increase, prior to realeasing gas into the system. Not sure if this is correct?

[Brian_UK]

Mick, I know that the make is different from your but this service book from Mitsi explains quite a bit and should prove useful to you. It's in pdf format so I would suggest you right click on the link to 'save' it for reading later.

http://www.bdt.co.nz/comfortmaster/data/manuals/power_inverter_r410a_construction.pdf

Cheers.

[mick2me]

Comprehensive information there

Thanks.