Leakage in manifold while charging R410a

Hi,

I am new in the refrigeration field, I am still learning.

One of these days, I was trying to charge a split air conditioner which works with R410a. I was charging it in the low pressure side because it didn't have a service valve in the high side. Before, I had read that it is recommendable to charge R410a in the high pressure side because the refrigerant should enter into the system in its liquid form. But, as I said before, this system didn't have service valve on the high side. So, I charged it in the low side and slowly (to avoid liquid refrigerant in the compressor). To do so, I opened the cilinder valve copletely and I was opening (just a little) and closing the manifold's low pressure valve many times, In this way , I expected, the refrigerant would enter slowly into the system. But after some opening-closing cicles, the refrigerant and oil began to leak through the manifold joints in the low side. I quickly closed the valve in the refrigerant cylinder, and the leakage didn't stop so I disconnect the manifold from the service valve in the air conditioner. While the "gas" was going out through the manifold, some ice formed near the leakage joints. I thought the manifold got damaged, but to be sure, I decided to connect it againt to the service valve in the air conditioner, but it worked well this time: there wasn't any leakage.

It seems that the manifold doesn't work properly under low temperatures, at least this was my conclusion.

Could anybody explain what happened? Why did the the refrigerant and oil begint to go out through the manifold while I was charging? Why didn't it happen the second time I connected the manifold?

Hi Hjnm and welcome, both to the forum and our trade,

OK,
Without actually being there, what I believe to happen its that you got a manifold that leaks.

When you got gas in the manifold the leaks will be small, not much gas will escape from a tiny hole/leak, and therefore the leaks will be hard to spot BUT as soon as you get liquid inside the manifold the leaks will become significant. This is purely because more refrigerant will escape from the same hole the denser the refrigerant is.

Changing seals and even valves in manifold and hoses will become second nature as your experience in our field grows.

:cool:

You should always leak test your gauge manifold and hoses before actually starting to charge a system just to ensure you have no leaks and that the correct amount of refrigerant is charged into the system with your weighing scales, use an isolation valve at the point of charging onto the system, keep this valve closed then open the cylinder charging valve, open the manifold charging valves so that you only have one final valve left to open, at the point of the hose connection to the system, but before opening this valve, leak test your manifold connections, hoses, charge connection on the cylinder when they are all pressurized with gas. Note the weight on your scales, if all is ok , then open the valve and charge to the correct weight.