VRF Systems Servicing

[weeliang82]

Hi guys,

I'm a newly graduate engineer and I had been working in the air conditioning industry since 8-9 months ago, promoting VRF system.

I have questions regarding VRF system that I want to know. Hope you guys can help me.

1. If I need to service the Fan Coil Unit or to change it, what will happen to the refrigerant in the system? Do you guys normally install some form of valve (on/off valve) when doing the installation for VRF system?

2. What do you think on the comparison between Digital Scroll and Inverter Scroll system? From my research, I believed Digital Scroll is way better, lots of people still believes Inverter Scroll is the best technology between the two.

[taz24]

Hi guys,

I'm a newly graduate engineer and I had been working in the air conditioning industry since 8-9 months ago, promoting VRF system.

I have questions regarding VRF system that I want to know. Hope you guys can help me.

1. If I need to service the Fan Coil Unit or to change it, what will happen to the refrigerant in the system? Do you guys normally install some form of valve (on/off valve) when doing the installation for VRF system?

2. What do you think on the comparison between Digital Scroll and Inverter Scroll system? From my research, I believed Digital Scroll is way better, lots of people still believes Inverter Scroll is the best technology between the two.


1 No valves. refrigerant has to be removed.

2 Some figures show the digital scroll to, be able to reduce in capacity to 20% of total, where the inverter is only about 30% I belive?

taz.

[DEVIL]

welcome to the forum weeliang82

1. If u need to replace a indoor unit , u recover the refrigerant with a recovery station and recharge the unit after replacement

2. Digital Scroll is the Copeland approach on the idea , and it's a little bit borrowed from the screw compressor.
I don't consider to be one way better then the other they have advantages and disadvantages,

http://www.digitalscroll.com/sb300/portal/home/normal/17/show/0/19

and u can search on the forum for more info

[weeliang82]

Thanks for the reply...

But what you mean by recovery station? Some form of temporary storage equipment that lets you store all your refrigerant in it?...

[monkey spanners]

But what you mean by recovery station? Some form of temporary storage equipment that lets you store all your refrigerant in it?...

Yes, a recovery machine and one or more recovery cylinders depending on the size of the system. The refrigerant can either be put back in when the work is completed or depending on its condition sent away for cleaning/destruction and new refrigerant charged into the system.

[Contactor]

Hello

For sevicing it's unlikely you will need to change the fan coil unit. Most parts can be easily changed.

Pumping down VRF is not an option so you will need to recover all refrigerant before any gas work.

[Thermatech]

For most maintenance & service work at indoor units there will never be any need to disconnect the indoor unit from the refrigeration system.
Therefore to make installation cost as low as possible refrigerant isolation valves are not normally installed for each indoor unit.

However in the very unusual case of indoor unit removal from the system, normally the service engineer can pump most of the system refrigerant down to the outdoor unit & shut service valves, then use a refrigerant recovery machine to recover the last small remaining volume of refrigerant into a recovery cylinder.
The time this operation takes depends on the VRF system size but can often be complete within 1 or 2 hours.

The service engineer can then carry out the replacement of the indoor unit, pressure test, evacuate & recharge refrigerant.

The digital / inverter debate rumbles on.
Each manufacturer will highlight the advantages of its own system technology & try to hide the faults & disadvantages.

I suspect that digital scroll is attractive for air conditioning contractors who are not confident to make repair of inverter circuits & also if it happens to be a slightly cheaper option.

Here in the UK digital scroll VRF has only made a very small impact as most of the established VRV / VRF manufacturers use inverter technology & contractors have been installing & maintaining those systems for up to 17 years so they have much experiance & confidence in the inverter technology.
The digital scroll has been used by the budget cost manufacturers as this seems to fit well with the ' make it cheap ' concept.
All the big premium brand manufacturers continue to develop the inverter technology.

[DEVIL]

I advice to recover it all , and not go with the pump down, because VRF's are mainly R 410, and it will fractionate and if u recover the refrigerant and don't add it back exactly the same, plus adding the lost parts from a new receiver u might have problems from unknown reasons in the future (but allsow u might not have eave the smallest problem ).

But how it usually goes u assume the responsibility and do it the way u like it.

And as the other posters replayed u probably don't have to remove it , because it's not like a fridge, or a TV , u get it down go back to the store and they replace it with a new one, VRF/VRV are typically for experienced contractors (not that it always happens that way) and they replace any part of it excepting the coil without removing the indoor unit