Rule of thumb for quantity of refrigerant in a system

[hyperion]

Is there a way of quickly/roughly estimating the amount of R22 refrigerant in a DX system? Reason for asking, we have to price to decommission a Daikin condensing unit on a DX system, the condensing unit is rated as 178kWatt duty.

[The Viking]

Daikin DX unit at 178 KW???

Are you looking at a VRV system with multiple outdoor units?

:cool:

.

[Brian_UK]

Price for a 63kg bottle, that should cover it.

[hyperion]

Thanks for the info Brian.
Viking, Daikin ER60 condensing unit matched to a 4 section DX coil.

[monkey spanners]

Think the big reco bottle can only be filled to 45kg. When i've done stuff like this i usually give them an estimate rather than a quote, you can take reco bottle back so long as the seal is still on so it can make sense to take a couple if you're not sure how much a system holds. (i have a couple of 10kg bottles i own so helps in situations like this and when wholesalers are out of stock)

Depends if customer wants a fixed price i guess. No idea how much it would hold though!

[hyperion]

Thanks monkey-s, that was my thoughts as well, to take an extra couple of small cylinders just in case.
As it has turned out, my estimate/quote ended up being severly undercut by competition, so we lost the job.
Must do a bit more research to try and establish a rough rule of thumb for next time. It is relatively easy with sites that have F-gas registers and splits systems that are correctly labelled. Oh I was dreaming then!!

[monkey spanners]

Trouble is you never know if the people who undercut are even taking the refrigerant back for recycling or using it elsewhere/letting it out...

[hyperion]

Monkey-s, that was my thoughts. Surely no-one reputable would just let the gas go, would they? Oh dreaming mode again!! Must stop dreaming and get into the real world.
Turns out that the competitions price was a third of my quote. Either they were fed more info about the site or they have just taken a "punt" to get some work in.
Thinking about it, if they get 50kgs of R22 and were to somehow find somewhere to re-use it and charge it out at R22R prices, that would turn it into a very profitable effort. Only dreaming again!!