Mini Split Evacuation Question

Tintin

I am replacing the air handler on a Mr. Cool 12k min split that developed a small leak due to corrosion. I am wondering once I connect the new indoor unit can I evacuate everything in the system with a vacuum connected to the service port with both the suction and liquid lines open? I don't want to use/recover the old 410a in case there was contamination from the leak. Will the vacuum suck everything out through the suction line in vapor form or will there be some 410a in liquid form still left? I want to remove everything from the system and have it hold a vacuum, before having a tech come and put new 410a in. Thank you!

Big Ed_4

You will first need to pump the system gas into a recovery bottle . Do the work needed.. Check for leaks with 500# nitro..... Now we evac to remove every thing else ... Need to do the steps .

Tip: To prevent the growth in the inside ... Seal the hole through the wall....

ratio

You must recover the old refrigerant & dispose of it correctly. (It does not need to be reused.)

Did you look inside the unit for service ports? There's usually a suction and liquid port in there somewhere.

pecmsg

What liquid line? 

Minis don’t have a liquid line?

EdTheHeaterMan

pecmsg said:

What liquid line? 

Minis don’t have a liquid line?

Really? Then why do they have two pipes? A larger and a smaller! And what does the condenser coil do to the refrigerant? Or it it called something else? There is an evaporator coil and a almost condensed coil. How does that work? If there is no liquid line then what does the evaporator coil evaporate?

ratio

There's the 'mixed phase' (their name) and suction lines going to the indoor unit, but there's an honest liquid line inside the outdoor unit between the condenser coil and the EEV(s), and at least the last few Mitsubishi mini splits I've worked on have had a port on it, as well as a suction port, separate from the external port for evacuating the lineset. I wouldn't like to try to vac down the whole system using just the lineset port.

Tintin

Thanks for the info. Yeah, there's only a service port on the suction line. I'm just curious about what pulling a hard vacuum will remove? If both valves are open (suction and liquid) does the vaccuum remove all the 410 whether it be in liquid or vapor form? I.e. If there's some 410 in the condenser in liquid form will a vacuum remove that? Or only trace amounts of 410 vapor, water, air?

Tintin

And how much nitrogen is needed to test a 1 ton 12k btu unit?

pecmsg

EdTheHeaterMan said:

pecmsg said:

What liquid line? 

Minis don’t have a liquid line?

Really? Then why do they have two pipes? A larger and a smaller! And what does the condenser coil do to the refrigerant? Or it it called something else? There is an evaporator coil and a almost condensed coil. How does that work? If there is no liquid line then what does the evaporator coil evaporate?

The metering device is inside the outdoor cabinet. Both lines are suction lines. That is also why there insulated separately.

pecmsg

Tintin said:

Thanks for the info. Yeah, there's only a service port on the suction line. I'm just curious about what pulling a hard vacuum will remove? If both valves are open (suction and liquid) does the vaccuum remove all the 410 whether it be in liquid or vapor form? I.e. If there's some 410 in the condenser in liquid form will a vacuum remove that? Or only trace amounts of 410 vapor, water, air?

Replacing the indoor section all that's needed is pulling a vacuum on the gauge port at the outdoor section. That will evacuate the line set and indoor section.

pecmsg

Tintin said:

And how much nitrogen is needed to test a 1 ton 12k btu unit?

How long is the line set?

pecmsg

ratio said:

There's the 'mixed phase' (their name) and suction lines going to the indoor unit, but there's an honest liquid line inside the outdoor unit between the condenser coil and the EEV(s), and at least the last few Mitsubishi mini splits I've worked on have had a port on it, as well as a suction port, separate from the external port for evacuating the lineset. I wouldn't like to try to vac down the whole system using just the lineset port.

Mr. Cool is not even in the same category as Mitsubishi. Mr. Cool is one of the cheapest throwaway online units.

Tintin

pecmsg said:

Thanks for the info. Yeah, there's only a service port on the suction line. I'm just curious about what pulling a hard vacuum will remove? If both valves are open (suction and liquid) does the vaccuum remove all the 410 whether it be in liquid or vapor form? I.e. If there's some 410 in the condenser in liquid form will a vacuum remove that? Or only trace amounts of 410 vapor, water, air?

Replacing the indoor section all that's needed is pulling a vacuum on the gauge port at the outdoor section. That will evacuate the line set and indoor section.

Will it evacuate the condenser too if both valves are open?

Tintin

pecmsg said:

And how much nitrogen is needed to test a 1 ton 12k btu unit?

How long is the line set?

It’s a 16’ line set.