Mini-Split Repair

The Client called complaining of a problem with the ductless mini-split system; we began by checking the unit that supplies air into the living room, a 12,000 BTU system. The client had an impression that the unit was not cooling strongly. It turns out that the mode setting on the system was in cooling mode, prohibiting the full BTU from coming on. We hooked up the refrigerant analyzer to the system and determined that the levels of refrigerant were within range. No service need.

On the system that has three zones, we found it the outdoor condenser with 35 psi of vapor refrigerant, indicating a leak in the system, in order to determine what the leak is, we need to pressurize with nitrogen take all the indoor units apart and start looking for the leak on the joint connection connections, then once the leak is found, hopefully it will be at one of the flare connections. We will fix it, vacuum the system, and recharge with new refrigerant.

With the client permission, we began the leak search test, pressurized the system with nitrogen at 480 psi , then began expose all the indoor unit connections as well remove all the external covers to expose the entire copper line set and begin to search for connections along the way.

The long run that goes from the condenser unit to the second-floor units. All the exposed line set is one continuous line, which is great; that’s exactly what we want to see, on the indoor units the bedroom that is close to the back wall of the house that’s the one that we have found traces of oil on the connections and that’s what the client has mentioned that another contractor has previously repaired last year. Although when we tested the line connections, we could not find any leaks. The other unit, the other bedroom, was also OK: no leaks, no signs of oil. The unit for the first-floor bedroom was also dry: no oil, no leaks.
We let the system stay on pressure for over an hour and couldn’t register any pressure drop.
We then begin the process of evacuating the system. We run the vacuum pump for total of an hour with two intervals of breaking the vacuum with nitrogen..
After that, we have charged the system with the new R410A refrigerant , test the system inside and everything is working fine only time will tell how this is going to work but at the moment everything seems perfect.