I just purchased a split air con unit from ebay. This one to be precise.

http://www.ebay.co.uk/itm/like/BERGDORF-24K-BTU-AIR-CON-HEATER-INVERTER-PLUG-AND-PLAY-NO-VAC-PUMP-REQ/261994675427?hlpht=true&ops=true&viphx=1&_trksid=p5197.c100068.m2280&_trkparms=ao%3D1%26asc%3D20140211130857%26meid%3Dfdaf6cce39d24ee484d3784f1c9c060b%26pid%3D100068%26clkid%3D351686000653122178&_qi=RTM2063723

The seller goes to length and states in the title “No Vac Pump Req’d”

The item arrived today and whilst reading the instructions it does state using a vac pump to purge the system of air prior to releasing the refrigerant gases. It does not take a rocket scientist to work out that if you don’t purge the air it will just get mixed in with the refrigerant gases.

I luckily have a vac pump as I use it for fibreglass, but am I correct in thinking this seller is basically misleading buyers into installing a system incorrectly or do systems exist that auto purge the air from the pipes (can’t see how it could)?

Thanks

A lot of this went on with the quick coupling connections. B&Q did exactly the same thing. I’ve know people purge the air out with just the pre charged refrigerant gas and units be fine, it’s a long way from best practice though.
I’m assuming you know what you’re doing, and you’re not going to vac the gas out?

Unless they have degree in Air-Conditioning they would be a technician.

😉

Plan was to create a vac in the system before releasing the pre charged gases from the outdoor unit into said pipework. The only question I have is although I understand how to connect my vacuum to the system I don’t quite understand how I uncouple the vacuum system from the pipework and still maintain a vacuum?

The instructions that came with the unit are rather naff.

Not an A/C engineer but… Pulling a vacuum would also prove the system doesn’t leak before filling with refrigerant.
Edit— a Non return valve will help keep a vacuum in the system.

Are there any service valves? Look like this, prob located where the quick couples are;

Google “Back seating service valves”, should help.
Should be a schraeder fitting if not.

Pulling a vacuum would also prove the system doesn’t leak before filling with refrigerant.

Holding a vacuum would be a better indication; pressure testing with nitrogen is the only real way.

Oh, and OP; that’s pretty expensive for a chinese 7kw wall mount!!!Sorry!!!

There is a 2 way valve on the outer unit. Can you explain why using nitrogen is better for a leak test than the unit holding a vacuum?

To me, using +ve pressure equates to a -ve pressure. Both will indicate whether the system is air tight. Keen to understand.

I’ve seen plenty of systems hold good vacs and fail pressure tests. That’s why you pressure test (it’s not just moisture removal).
Oh, and just remembered (I’ve not been on the tools for a good few years now); I’m sure that the R410a systems have a different size fitting on the valve than the old R407C/R22/R134a systems (due to the higher operating pressures), so you’re either SOL or you’ll need to buy (at least) a hose (I think). I deally you’ll want a system analyser/manifold gauge.

http://yellowjacketuniversity.com/articles/hoses-and-fittings-for-r-410a/

Cheers wrecker.

If there is a leak and you’re leak testing with a vacuum, it’s just going to drag moisture into the system. There’s also no strength test with a vac, system could hold a vacuum perfectly fine but as soon as you pressure it up it might blow a weak joint apart, especially with 410a as it runs at a reasonably high pressure.

In the UK R410a lines and gauges are 5/16″. I haven’t a clue where the unit linked above is manufactured though so it could have 1/4″ or 5/16″. I don’t know how they can get away with saying ‘no vac pump req’ and then advise purging the pipework to push any air/moisture out, terrible practice.

Most people here have an idea on whats what, although it is a common misconception that with quick coupler hoses , you can just connect up and go. This is poor practice as said by others but not for reasons of just non- condensibles ( air) but also the worst thing which is moisture. My other thought buying an air con unit which will almost have no spares back up for the future. It would pay to get the system actually connected, pressure tested with nitrogen and probably vacced out and run up by a professional, rather than doubt and guess. its a lot of money you could loose by mis installation. Most modern a/c systems use R410a , which do use a 5/16 hose and fittings, although you can buy 5/16 to 1/4 adaptors to use the 1/4 hoses and gauges.
Any questions, fire away.

Thanks for the replies here. I feel like I have been duped by the seller and am rather annoyed. This to me is a classic example where I feel Trading Standards should be contacted.

The seller tells me one thing and the instructions tell a different story. I am going to print screen the ebay advert and ring the seller and tell him he needs to either take the unit back or knock me some cash off so that I can either.

a) Hire a hvac engineer to install the system.
b) Purchase the required nitrogen and vac manifold so that I can install it correctly.

What is even more concerning is the domain address for Bergdorf is registered in the Cocos Islands!

http://bergdorf.cc/

Umm. Maybe return the unit?

They aren’t alone, as I said b&q were doing exactly the same thing a few years ago on a massive scale.

They aren’t alone, as I said b&q were doing exactly the same thing a few years ago on a massive scale

That is shocking and misleading.

Commonplace in spain. I installed one for my ex-Gfs dad. I refused to purge the air out though, and made him get a local Ac engineer in to vac it out.

Most of these ‘branded’ units are Chinese stuff, which are not the best. Depends on the application you are using it on, to be honest. They show a comms set up on their website and that’s one place I would never put an unknown branded unit in. My mate bought a Worcester Bosch branded a/c unit , as he is a heating engineer and ‘got a deal’. He wanted it installed at his dads house. I piped it in and pressure tested it, vacced it and they all come precharged. It is not made by Bosch or Worcester, but a Chinese rebadge. It works a treat, but for how long and spares back up is always a worry. We install branded makes like Toshiba, Daikin, Mitsubishi, Samsung etc, which although are more expensive , the support , energy saving over inferior products and general quality of the units do show over time.