How do you charge a R410a inverter split?

[AC noob]

Hi guys,

I have possibly a simple question,

But how do you charge an inerter split system? Im guessing it's quite hard to over charge one of these systems. But i have to add gas to a system that is short, due to someone extending pipe runs. Do i have to weigh the gas in with the calculations of the extra metres of pipe?

Thanks in advance

[Brian_UK]

In short, yes, always remove any old charge and weigh in the correct amount.

[install monkey]

best to refer to manufacturers recommendations, measure the piperun, the factory charge will be upto x distance, any extra pipework is usually charged at 30grm per meter- but refer to the installation guide, then label the unit of system charge.

[AC noob]

Ok thanks. But for an inverter do you need to run the system flat out on cooling or just half way. So it ramping at full capacity or only half.

[AC noob]

Of course, if you work out the calculations, it doesn't matter how you run it, because you know the exact amount. But what if you're just topping it up?

[install monkey]

charging of a split is critical, its easy to over charge, as the compressors are usually inverter driven and electronic expansion valves modulating to match the demand your pressures will fluctuate, weigh out the remaining gas, you have to pressure test with nitrogen to repair the leak then recharge

[AC noob]

charging of a split is critical, its easy to over charge, as the compressors are usually inverter driven and electronic expansion valves modulating to match the demand your pressures will fluctuate, weigh out the remaining gas, you have to pressure test with nitrogen to repair the leak then recharge

Let's say, i don't have a reclaim unit. And on install, the installers added extra pipe length but didn't add any refrigerant to accomodate. I'm going to this job to top up the gas to make it run sufficiently as the cooling is poor.

[install monkey]

you could try it, depends if the system has ever worked properly, if it worked ok then its lost performance then theres probably a leak on it

[moideen]

In short, yes, always remove any old charge and weigh in the correct amount.

dear brian,

is subcooling not relevant to findout the proper charging for R410a system?samelike the calculation of ambient temp+30f is the maximum saturated discharge temp.

moideen-dubai

[install monkey]

its too inaccurate, the lev start up in an initial mode,after 5-10 minutes then it starts to operate modulating as req, also the the compressor frequency is trying to ramp up to reach setpoint, it can be done but with aussie gas prices its probably cheaper to buy a new system

[monkey spanners]

Let's say, i don't have a reclaim unit. And on install, the installers added extra pipe length but didn't add any refrigerant to accomodate. I'm going to this job to top up the gas to make it run sufficiently as the cooling is poor.

If you don't have the correct tools to do the job, don't do it. Either purchase them or leave the work to better equiped technicians.

How do you know its just under charged from new and not under charged and also leaking without testing for leaks?

Sometimes a system only needs another 20g or so, you will not see any change on your gauges with this amount so how do you expect to get anywhere near the correct charge without weighing it in as per manufacturers specs.

[Brian_UK]

dear brian,

is subcooling not relevant to findout the proper charging for R410a system?samelike the calculation of ambient temp+30f is the maximum saturated discharge temp.

moideen-dubai

As many have said already, with these critical charged units the correct weight of refrigerant is the only way to go especially with inverter drives.

I recently had a small split, inverter, with reasonable superheat but which would suddenly loose the superheat as the expansion valve tried to compensate for a shortage of refrigerant; 300g out of 1.5kg it turned out to be short.

[AussieFridgie]

If there is doubt about whether the additional charge was not added, or if it was (maybe) lost, you have to scrap it, R410a is a blend Noob, if some of it has been lost it doesn't work that well anyway. Better for your customer to start from scratch with the manufacturers guidelines and go from there, otherwise you could overcharge. Also weighing in the charge means you can eliminate over or under charged as a cause of any problems.

[Acrisoft]

You guys are talking about TEV. Do you mean R410A mini-splits as Samsung and LG also use TEV, instead of a capillary tube or other fixed devices ?

[Craig22]

Of course, if you work out the calculations, it doesn't matter how you run it, because you know the exact amount. But what if you're just topping it up?

Topping up........ #illegal you can't just top up! You need to reclaim the gas! Measure the pipe run and work out the correct charge. Then vac the system and charge it! You should get all the gas in under a vac! The compressor being an inverter or fixed speed doesn't matter

[raison]

The term "topping up" doesnt sit well with me...

[chilliwilly]

If it has got a leak and not cooling, then it could have lost a considerable amount to cause fractionation, it isn't unheard of with blended refrigerants that have lost substantial amounts. In which case you might be better to reclaim and leak test, repair the leak if you find one. Then re gas with a fresh charge, this could iron out any problems with the system not working correctly, and you having to return and scratch your head trying to find faults that aren't there.

Or if its a new install and the charge in the system isn't sufficient for the extra run, then you shouldn't need to reclaim unless there is a leak. And I've just realised that this post is a month old so you've probably sorted it by now.

[alexaso]

http://www.epatest.com/faq/R410A/#T10

[chilliwilly]

http://www.epatest.com/faq/R410A/#T10

Yes that's true in most cases, but has anyone ever been to a job and ended up topping off near azeotropes after a sustantial leak only to find that the system doesn't work properly. And you end up fault finding and getting no where and giving yourself a headache, only after a while you decide to decanter and recharge with fresh and find the system performs better?

[stufus]

Have I missed something here??? The noob said he has to add gas due to additional paperwork on installation.
So as I see it, calculate additional charge run unit on cooling and lob it in job done, label it up and go to the pub...
Cheers
Stu

[install monkey]

additional paperwork!!!-yep it can be a pain in the arse!- if your referring to additional pipework then he should reclaim to prove he has the factory charge within the system, if it aint labelled,system charge then you cannot guarantee that additional was added and its leaked

Have I missed something here??? The noob said he has to add gas due to additional paperwork on installation.
So as I see it, calculate additional charge run unit on cooling and lob it in job done, label it up and go to the pub...
Cheers
Stu