Wrong pipes diameter - what now?

[igi]

Hello!

My customer have new house with installations for multi split system. Installed pipes diameter are 1/2" and 3/8".

I want install Mitsubishi sistem with outdoor unit MXZ-2A52VA and indoor units 2xMSZ-FD35VA.
Pipes diameter for this system is 1/4" and 3/8".

Can i reduce diameter on both sides of pipe with welding some pipe with right diameter?

Pipes are approximate 25m long.

Will system work? I calculate that i must add approximate 200g extra gas. Is this ok?

Thank you!

Igor

[Brian_UK]

Can you push some 1/4" tube inside the 1/2", that way you will have the right sizes.

[powell]

Can you push some 1/4" tube inside the 1/2", that way you will have the right sizes.

I was thinking the same thing.;)

25m (82 feet) is a long line set run. I would definitely check with Mitsubishi and get their recommendations for this length.

[Sandro Baptista]

Hello!

My customer have new house with installations for multi split system. Installed pipes diameter are 1/2" and 3/8".

I want install Mitsubishi sistem with outdoor unit MXZ-2A52VA and indoor units 2xMSZ-FD35VA.
Pipes diameter for this system is 1/4" and 3/8".

Can i reduce diameter on both sides of pipe with welding some pipe with right diameter?

Pipes are approximate 25m long.

Will system work? I calculate that i must add approximate 200g extra gas. Is this ok?

Thank you!

Igor

What's the problem with pipes? Let see: You have 3/8" instead of 1/4" for liquid line » Good/BETTER (less pressure loss, less flash gas at TXV); you have 1/2" instead of 3/8" for suction line so less suction pressure loss. The only problem I see is the lack of oil return. However I think it should have no problem because I bet the vapor velocity will be still sufficient. If the condensing unit is below the evaporators levels no problem will have.

[igi]

Can you push some 1/4" tube inside the 1/2", that way you will have the right sizes.

No chance for this...

[multisync]

No chance for this...


Yes, good luck with that one brian feeding 25m of 1/4 up a 1/2 hole!

[chemi-cool]

Just let it work, With 25 m lengths, it will be fine.

This Ac we are talking about, not science.

[malkiaizrod]

no problem just add extra charge

[momo]

Main problem arises with the 3/8 replacing the 1/4 the valve/flow control is most likely in the outdoor unit (check this) this will lead to the refrigerant flashing/expanding too early before the evaporator. Compensating by more gas on these lengths would lead to more refrigerant in the system than that which it was designed for. Be aware of other consecuential effects when used as a heat pump.

[igi]

Main problem arises with the 3/8 replacing the 1/4 the valve/flow control is most likely in the outdoor unit (check this) this will lead to the refrigerant flashing/expanding too early before the evaporator.

This is my greatest fear...



[quote=momo;197699]Compensating by more gas on these lengths would lead to more refrigerant in the system than that which it was designed for. quote]

I will add only 200-300g of refrigerant. This shoud not be a problem!


[quote=momo;197699]Be aware of other consecuential effects when used as a heat pump. quote]

?


Tomorrow i will see what will hapend... :(
Thank you

[Sandro Baptista]

Main problem arises with the 3/8 replacing the 1/4 the valve/flow control is most likely in the outdoor unit (check this) this will lead to the refrigerant flashing/expanding too early before the evaporator.

I don't see how replacing 1/4 by 3/8 will the refrigerant flashing sooner...by the contrary.

Igi, I believe no problem will happen.

Give us feedback as soon you can.

[Sandro Baptista]

Hi Igi,

How is the AC working? Have it started up?

[igi]

Hi Igi,

How is the AC working? Have it started up?

Yes I start it today...


and its working like a charm :) for now...



Thank you!

[Sandro Baptista]

Great to hear that.

Keep in touch igi