Reducing Pipe Sizes

[Clivo]

Hi everyone
I visited a prospective client today to quote for 8 mitsubishi inverter splits, mainly for bedrooms all with pre installed pipework. 6 of them are Ok but the client has requested a 2X1 multi split unit to be installed on a terrace my only concern is that the pre installed pipework is in 1/4" + 3/8" on one set of lines and 1/4" 1/2" on the other set of lines mitsi only make 2X1 inverter splits with 1/4" + 3/8" connections If I reduce the ends of the 1/2" pre installed pipe to 3/8" will this cause a problem with the flow of refrigerant? I just wanted to check before giving the quote.

Thanks in advance
Clivo

[The MG Pony]

how well installed is the pipe? Oil return would be my first concern, other then that I can not see any other then the charge may need to be adjusted.

[sinewave]

How did the 'Pipe-work Installer' choose his sizes if he didn't know which units were being put in?


Why is the original installer not fitting the units?



Sounds like trouble to me, I'd steer well clear if I were U!

[Peter_1]

If you re-calculate the speed in the tubes that Mitsubishi propose, then you will see that this speed is high.
I shouldn't be afraid that they are just one size bigger.

But as Sinewave suggested, perhaps try figuring out why the original installer isn't asked to do this job.
Pehaps because this client isn't paying that well.

[Clivo]

Thanks for all your input, here on the costa del sol we have lots of buildings going up everywhere, it is usual practice to have the pipework and drains pre installed as they can be hidden in the walls whilst the construction takes place. the installer of this particular pipework had assumed the client would choose a non inverter system as most of the non inverters of 3.5kw and above use 1/2" and not 3/8" for the gas line, I got the job anyway so will fit the kit and adjust the charge accordingly to the correct paramaters.
As a side note I have just tried to arrange to get some recovered/contaminated R22 destroyed, to my horror even though I can change my Uk registration to the Spanish system, to get it destroyed it has to be sent to france and costs €30 per kilo =£22 + transport, my supplier tells me from 300 tecs who have the correct papers in the last year, he has aranged only 10 kilos to be destroyed, now I know why the Spanish just vent it to atmosphere instead of doing the right (and legal) thing.

Clivo