new 410 old 22 pipe work

[MRC Guts]

g day blokes
410 is starting to take over from 22 here in far north oz an old 22 systems are being replaced with 410 systems the problem is you cannot always replace the pipe work...as it was run during contrustion of the building.
can the 22 pipe work be used??
it would have to be flushed clean to get any old oil out and i have been told you only have to weld new ends on the old pipes to get to get the stronger flares...
the units here are mainly cooling only so the high pressures on heat are not a problem...what do you good folks think???????
might get a cold one out of the esky

[Renato RR]

No you can use old pipes.
Why you can?
Try once and you will found out.

Best regards,
Renato

[The Viking]

Do you have Toshiba or maybe Mitsubishi Electric system down there in the darkness?

If you do, have a chat with them, here in UK both have launched (or are in the process of) systems that will do just that.

IIRC, Mitsu does VRF R410a systems that can replace old R22 ones and Tosh does splits. They even claims that these systems can re utilise the pipework without much cleaning. In fact, Tosh's sales pitch goes like "the system has to run so that you can pump it down, then you just replace the indoor and outdoor units together with the flares, pull a good vacuum and away you go"

[frank]

One thing to consider is that the suction line on R410A is normally a size smaller than R22 systems.

If you manage to flush the old pipework and feel confident that all the mineral oil is out, then yes, I would agree that you could re-use the old pipework.

But, if it is a short straightforward connection between indoor / outdoor units and oil return doesn't appear to be a problem then you should be OK. If you have a long difficult route though, you may have oil return problems via lower suction velocities.

[wkd]

You may need to be careful with the pipe wall thicknesses as R410 A runs at higher pressures.There are some pipe diameters that are OK but other require increasing.

[The Viking]

One thing to consider is that the suction line on R410A is normally a size smaller than R22 systems.

Ah, but that's were they are cleaver,
Tosh claims that their units will cope with several sizes above the required one, the only thing a larger pipe size will do is reduce the max pipe run length.
Or, so they claim, I haven't heard anybody actually installed one.

[Paul@paulrobert]

I have installed Daikin and Mitsi systems using the old 22 pipework as they have a built in scrubber circuit which activates for the first 30 mins of initial running then permanently shuts down, be careful of pipe diameter and pipe run length, ask the dealer tech line to work it out for you as it can save a lot of bother and its easier than doing it yourself

[Obi Wan]

Hello All,

At the time Daikin launched the R410A Sky Air inverter, they tested the feasibility of using existing R22 pipe work. As a result they came up with some restrictions which are adequately answered in the FAQs below. To date Daikin will only allow the existing R22 pipe work to be used on the RZQ-B series systems provided you follow the restrictions, otherwise no warranty. Hope the below will allow you to make an informed choice.


Frequently asked questions


Q1. Can any kind of existing piping be re-used?
A1. NO! There are some restrictions.
1.R410A pressure resistance requirement must be met.
2.Piping length must not exceed 50m, and the air conditioner must allow pump down operation.
3.No extreme deterioration of oil quality in the existing piping.
4.No record of compressor failure. (The scales adhered inside the piping cannot be sufficiently cleaned by pump-down operation.)

Q2. Can any existing piping be cleaned to the extent of less than 1% mineral oil level?

A2. Any piping in compliance with the Sky Air piping limitations (maximum difference of elevation and piping trap) can be cleaned to that level.

Q3. What if no pump-down operation is performed?
A3. Large quantity of mineral oil will remain inside the refrigerant system, not allowing the piping to be reused as it is.

Q4. What will the cooling and pump-down operations do for the existing air conditioner?
A4. Performing the cooling operation for 30 minutes or longer will dissolve the mineral oil remaining within the refrigerant system.
(The oil will be dissolved into the refrigerant and circulate.)
A through pump-down operation will recover the mineral oil from the field pipe work.

Q5. Can pump-down operation fully remove the mineral oil within the system and completely clean up the piping?
A5. Although the mineral oil cannot be removed 100%, the remaining quantity can be reduced to a constant low level (max. 1%).

Q6. Are there any problems caused by the1% of mineral oil remaining within the system?
A6. Reliability has been proved by the long-term durability tests according to the expected product service life (13 years).
Allowable contamination level has been established against the contamination that might be caused by the remaining mineral oil.
While employing the latest electronic expansion valve, it has been proved that the requirement “No corrosion in the needle parts” can be met under the allowable contamination level condition.

Q7. What harm will the mineral oil do if it remains in large quantity?
A7. Contamination will exceed the allowable level in a short period of time soon after the start of operation, leading to the equipment failure.
Highly corrosive chlorine ions will increase and cause corrosions of brass and iron, resulting in the damaged electronic expansion valve.
Ethereal oil will be subject to oxidation degradation and polymerization, leading to the clogged capillaries.

Q8. What is the difference from Melco?
A8. As Melco uses the ester oil which has little tolerance to water inclusion, it is necessary to remove water content by using an activated charcoal filter.
RZQ-B series, having the proven reliability through long-term durability test, needs no auxiliary device such as a filter.

Q9. What about the models other than RZQ-B series. Are they compatible with the existing piping for Sky Air or RA / VRV?
A9. For the models other than RZQ-B series, the existing piping cannot be re-used because the allowable contamination level has not been evaluated.
For new models to be released from now, the allowable contamination level will be evaluated aiming to increase the models compatible with the existing piping.

[MRC Guts]

thanks for the feed back guys good stuff....
we have all sorts of equipment daikin, mitsu, carrier. lg, gree,
blue star and heaps of other stuff some of which i would not recommend to anyone...
land of darkness mr viking...sunrise 5 30am sunset 7 40pm haha
now i better check the ice in the esky

[Temprite]

I guess only time will tell but if there was no other choice than to use the existing pipework then you might as well go for it.

When the change was made from R12 to the newer gasses, I vaguley remember that it was suggested that you use a different set of gauges for every different gas to avoid contamination.
Anyone doing this
I personally dont have enough room in my truck for 8 different gauge sets.

But I think that as 410A becomes more popular people may relax a little.

[fridg]

Here is a thread here that might be useful MRC

I know i learned something from it

http://www.refrigeration-engineer.co...ead.php?t=3931