Adding r410a to minisplit with unknown charge

[sreeb]

I have a mini split with a slow leak and want to add refrigerant without evacuating it.

I know a full evacuation with fill by weight is the "right" way to do it but I only have a single recovery tank, which currently has some r134a in it, and I want to avoid buying another just for this.

High side is internal to the outside unit and it uses a capillary tube. I only have access to low side pressure measurement.

Service manual has this table:



Can I use this table to add charge to it and get close enough?

I don't see where the service manual defines ODT/IDT.

ODT is outside ambient temp?

For IDT of 75/63, 75 is inside ambient temp? What is the 63 indicating?

 

[Terry D]

I would consult the manufacture and ask them, I would think they stand for indoor temp and outdoor temp, but what about the double temps in the IDT column. I would call them. But as you know, minisplits are there own animal. Best is to weigh in the charge. Have you looked for a the leak

 

[Gizzi]

The manufacturer charging chart should get you close to where you need to be. ODT is for outdoor temperature, the slash numbers for IDT (indoor temperature) appear to be for wet and dry bulb temps.

Is there a reason you can't pump down the lineset and evap into the condenser, or is that where you suspect your leak is? That way if the leak is by a flare fitting or in the evap coil, you can fix it so it doesn't leak anymore, and avoid having to recover the entire charge.

 

[sreeb]

I would consult the manufacture and ask them, I would think they stand for indoor temp and outdoor temp, but what about the double temps in the IDT column. I would call them. But as you know, minisplits are there own animal. Best is to weigh in the charge. Have you looked for a the leak

I'm not sure if I have found the leak yet. One of the fittings looked suspicious when sprayed with the bubble fluid but that might have just been from the wind. Too much wind for a leak detect wand. I loosened the suspect fitting, re-torqued to 10% over spec, and it look quieter but I'm not sure.

I also tried to add some dye but I think more ended up on me than in the system. I will see if it reveals anything next weekend.

 

[Terry D]

I'm not sure if I have found the leak yet. One of the fittings looked suspicious when sprayed with the bubble fluid but that might have just been from the wind. Too much wind for a leak detect wand. I loosened the suspect fitting and then re-torqued to 10% over spec.

I also tried to add some dye but I think more ended up on me than in the system. I will see if it reveals anything next weekend.

Defiantly check the flares. If leaking, it is very possible you will have to re make the flare up anyway. I'm also thinking the second temp
in the indoor column is wet bulb

 

[acmikee]

it would be best to reclain the system, evac and weight in correct charge

 

[chris142]

You want to mix refrigerants?

 

[Jackfre]

Having been in your position I twisted and turned and tried to figure out how to McGiver this thing. Your first problem is you do not know if you have a leak and you “aren’t sure.” Again, been there. In desperation I finally outsmarted myself and recovered t he charge, pumped it up with about 500# Nitrogen and found a leak on a flare. Re-flared, re-pressured, tested, it held and I weighed in the right charge and that unit has been golden since. Anything else you do resembles my golf game. Hit and hope!

 

[sreeb]

The manufacturer charging chart should get you close to where you need to be. ODT is for outdoor temperature, the slash numbers for IDT (indoor temperature) appear to be for wet and dry bulb temps.

Is there a reason you can't pump down the lineset and evap into the condenser, or is that where you suspect your leak is? That way if the leak is by a flare fitting or in the evap coil, you can fix it so it doesn't leak anymore, and avoid having to recover the entire charge.

I'm assume the leak is on the cooling low side.

If I can get the charge close, then I should be able to get it into heat mode which would pressurize the lineset and inside unit to ~400psi which should make any leaks easier to find. It doesn't seem to enter heat mode when low on charge though.

I should be able pump it back into the outside unit if I can locate a leak to fix.

 

[sreeb]

You want to mix refrigerants?

No, don't do that. It will be hard and/or expensive to get rid of them if you do.

 

[chris142]

No, don't do that. It will be hard and/or expensive to get rid of them if you do.

I know.but he said he wanted to add 134 to 410.

 

[C2F]

Sreeb.
1) What is the make and model number of the equipment?

2) as stated based on that chart for 75 indoor and 85 outdoor you’d want a 120psisuction. You’d want to read instructions. Some units need to be on a powerful mode.

3) many times system pressures mean nothing when charging a slow like on a mini split.
to get a LG picture frame unit running until I could return and find the leak I had to charge based off of Discharge line temp.

4) as stated above most leaks come from flares. I had to follow up on a new startup because they only pressure tested to 100psi. I didn’t see the flare leaking until I had the pressure over 400psi. After I cut out and reflared the equipment I took the nitrogen test to 600PSI as per manufacture specs

 

[sreeb]

Sreeb.
1) What is the make and model number of the equipment?

2) as stated based on that chart for 75 indoor and 85 outdoor you’d want a 120psisuction. You’d want to read instructions. Some units need to be on a powerful mode.

3) many times system pressures mean nothing when charging a slow like on a mini split.
to get a LG picture frame unit running until I could return and find the leak I had to charge based off of Discharge line temp.

4) as stated above most leaks come from flares. I had to follow up on a new startup because they only pressure tested to 100psi. I didn’t see the flare leaking until I had the pressure over 400psi. After I cut out and reflared the equipment I took the nitrogen test to 600PSI as per manufacture specs

Pioneer WYS009AMFI19RL

Once I get it charged well enough to enter heat mode, I should see 400 PSI at the flares and will look for leaks then. This assumes that the low charge is preventing it from entering heat mode.

 

[mrobins297aaa]

I have a mini split with a slow leak and want to add refrigerant without evacuating it.

I know a full evacuation with fill by weight is the "right" way to do it but I only have a single recovery tank, which currently has some r134a in it, and I want to avoid buying another just for this.

High side is internal to the outside unit and it uses a capillary tube. I only have access to low side pressure measurement.

Service manual has this table:



Can I use this table to add charge to it and get close enough?

I don't see where the service manual defines ODT/IDT.

ODT is outside ambient temp?

For IDT of 75/63, 75 is inside ambient temp? What is the 63 indicating?

63 is wet bulb temperature, 75 would be the dry bulb temperature or ambient

 

[mpire]

This is why my buddy brazed on regular fittings to both lines a few feet away. No more of this guessing ********.

 

[LS6 Tommy]

Proper procedure would be recover, pressurize with nitrogen, leak check, repair, evacuate and weigh in correct charge. If it's a small leak, and you find it and can "tighten up" a loose fitting or something similar, you can get away with charging by superheat IF you charge liquid.

Tommy

 

[sreeb]

I attempted to charge is using the pressure table. I interpolated to get 115 psi. Starting pressure was very low (~50 psi). Adding about 0.5 oz at time, the pressure moved up until it it hit 100 psi where it stalled even as I added another 2 oz. I quit adding at this point.

I can now enter heat mode which pressurizes the flare fittings, line set, and inside unit to 400+ psi. At this point, I still didn't find any leaks.

It now cools and heats well.

I don't think I can measure superheat as my only access to pressure is directly after the capillary tube on the outside unit in cooling mode.

For now it works. If it leaks down again, I will get my hands on a nitrogen bottle.

 

[AngryBeaver]

You want to mix refrigerants?

Reading comprehension is key. He specifically said he doesn’t want to pump it down because he only has a 134a recovery tank And doesn’t want to mix them.

I know.but he said he wanted to add 134 to 410.

can you not read either? If you can, then you’d clearly see the guy you responded to wasn’t trying to add 134a to 410. At no point did he mention adding 134a to a 410 system.