DIY Air Con. install with Vacuum pump

[srp]

I have ordered a wall mounted 'Easyfit' AC system and will be installing it my self :-)

I've not seen the installation instructions yet, but I gather that the gene ral idea with this sort of system is that you purge the air and moisture fr om the indoor unit by venting some of the R410a from the pre-charged outd oor condenser unit.

Now, being a bit of a perfectionist at times, I have started to research th e Pros /Cons and moral issues involved here. I might install a second one of these units at some point and I am concerned about the longevity/ effici ency and effectiveness of my AC systems !

As I understand it so far, I would just need to get a vacuum pump and a man ifold gauge set, Then connect the pump to the suction side on the condenser unit via the low side gauge and let the pressure fall to 0 psi over 15 min s or so. Doing this means that any water in the lines or wall unit will boi l off.

So then you close the valve on the gauge and check that the vacuum holds. N ext you can crack the high ( liquid ?) valve on the compressor and close it again when the gauge reads 100 psi. or so. This means I will be able to ch eck for leaks under a vacuum and also after I've released the refrigerant .

Assuming no leaks ( soapy water to boot ) then what ? I fully open both val ves on the compressor ?

Do I need to do any thing else before removing the hose from the Gas side s ervice port ?

I don't mind forking out for the gear to do the job properly, can always tr y to sell it on ebay !

Simon P

[harryagain]

I've not seen the installation instructions yet, but I gather that the general idea with this sort of system is that you purge the air and moisture from the indoor unit by venting some of the R410a from the pre-charged outdoor condenser unit.

Now, being a bit of a perfectionist at times, I have started to research the Pros /Cons and moral issues involved here. I might install a second one of these units at some point and I am concerned about the longevity/ efficiency and effectiveness of my AC systems !

As I understand it so far, I would just need to get a vacuum pump and a manifold gauge set, Then connect the pump to the suction side on the condenser unit via the low side gauge and let the pressure fall to 0 psi over 15 mins or so. Doing this means that any water in the lines or wall unit will boil off.

So then you close the valve on the gauge and check that the vacuum holds. Next you can crack the high ( liquid ?) valve on the compressor and close it again when the gauge reads 100 psi. or so. This means I will be able to check for leaks under a vacuum and also after I've released the refrigerant .

Assuming no leaks ( soapy water to boot ) then what ? I fully open both valves on the compressor ?

Do I need to do any thing else before removing the hose from the Gas side service port ?

I don't mind forking out for the gear to do the job properly, can always try to sell it on ebay !

The system is charged with a pre-determined wieght of liquid refrigerant. The exact weight will depend on whether or no there is a reservoir and if so how big it is.. (Having one is a good idea.) The sytem is usually marked with the type of gas and the weight of gas when "full".

There is a chart comes with the maintenance manifold gives the operating pressures for various refrigerant gases running at different temperatures for adding your own gas.

Some sytems have a sight glass to see the refrigerant level.

The sytems contains a dryer that removes moisture from the system. Moisture reacts with the refrigerant and produces an acid which attacks motor insulation.

The dryer is the little bulb between the condenser and the capilliary tube/expansion valve. You are supposed tochange it if the system is broken into.

Get a pre charged sytem. Not only do you have to buy the manifold, you have to buy gas, brazing equipment, leak detector etc etc. for a disparate system. Or get a "through-the-wall " system, no plumbing needed, less likelyhood of leaks.

[Onetap]

There's a guide to a DIY refrigerant installation here;

In that case it's for a computer cooling system, but the principles must be much the same. There's lots of information relevant to all vapour compression refrigerant systems.

I've never done any refrigerant work so don't take this as a recommendation.

[dennis]

On my split unit the hose has a valve on it and the unit has a valve on the connector. They are both sealed until you connect and there is no requirement to vent anything.

Does yours come with fixed length hoses, if so it is probably the same arrangement. If not you just vent some of the gas to flush the pipe.

[Andrew Gabriel]

You need to check the instructions, but I suspect 'Easyfit' means it simply plugs together with self-sealing connectors, and all the components are pre-pressurised.

Venting refrigerent to purge the system is now frowned upon (it's probably illegal in the UK). It's done with a vacuum pump, which some companies will hire you when you buy the system. You are supposed to have the relevant City and Guilds refrigeration certificate to do this (you are not allowed to test for leaks in an aircon system without holding the C&G certificate). You don't need this for installing the simple plug-together type.

[srp]

I know what you mean, there are systems that simply click together, but mine is not like that. A pump and gauge set is not all that expensive. Just trying to find the appropriate Youtube tutorial ! Note that I am not charging the system, the condenser is supplied with refrigerant already in it.

[dennis]

Its not going to do any harm if some of the refrigerant leaks out. Its not the sort that destroys ozone but you will upset the greens if they see you do it as they are simple folk that wont know the difference.