How bendy are aircon hoses?

[Julian]

Simple question below. Reason for asking follows is anyone is interested or has extra comments...

Question: How bendy is the hose that carries the gas between the internal unit and the external unit on a domestic split-unit aircon? It is something like a regular garden hose or are the walls much thicker so it is really quite rigid e.g. like domestic mains cable (the stuff hidden in the walls)?

Reason for asking: I have a split aircon unit where the internal unit has broken. I had one company come in to look and they told me that my unit is old and illegal now because it uses ozone-destroying gasses. I was thinking of replacing it anyway but the fact that parts for the old one are getting rarer and rarer and more and more expensive makes replacing it more attractive.

The problem is that, due to the change in gasses, new units use a different type of connection hose to connect to the external unit. The existing hose is really neatly ducted through walls and roof cavities to get to the external unit. The aircon company suggested changing the locations for both the internal and external units to make hose routing easier but what they suggest has lots of ugly surface mounted hose runs. I was wondering whether it would be practical to pull the new hosing through the existing duct for the old hosing. One could perhaps drill holes through the walls of the hose at the end of each and use a loop of string fed through the 4 holes (2 in old hose and 2 in new) to connect the end of the new hose very securely to the end of the old one and then carefully use the pulling out of the old hose as the pull wire to feed through the new one(*). Whether that has any chance of working depends on the rigidity of the hoses, the diameters (are new hoses bigger than old ones or smaller? And whether the existing routing has any very tight turns (which I haven't worked out yet).

(I realise I should have been saying "hoses" above since there are to and from hoses but please consider that as read. I can't be bothered to go back and change all the nouns, prepositions and verb agreements to fix it.)

I'd be most grateful for any info, suggestions, thoughts comments etc that anyone could offer.

- Julian

(*) An alternative 2-step process that might be better would be to attach a string to the old hose, pull out the old hose to pull through the string, and then attach the string to the new hose to pull it back through the now empty ducting where the old hose used to run.

[3george]

http://www.orionairsales.co.uk/pipe-ins ... -186-c.asp

Air conditioning is typically connected via small bore copper pipe as per the above site.

[richlist]

.......with Lots of insulation on the small bore copper pipe to make it look like hose.

[Julian]

So that'll be not in the least bit bendy then! Thanks for the info both of you. Talk about getting it all wrong. It was, as richlist observes, the insulating sleeve that made me think from pictures that it was some sort of garden hose-ish thing inside. This is all going to be very awkward. What a pain.

- Julian

[SteelCamel]

Do you actually need to replace the pipes? Unless they're leaking, you should be able to use the pipes you have and just replace the units.

[Julian]

Do you actually need to replace the pipes? Unless they're leaking, you should be able to use the pipes you have and just replace the units.

Sadly yes, I do need to get new pipes.

I actually just had another aircon engineer here a few hours ago who was more helpful than the first. He explained that it's not just a matter of different pipe diameters but because the old pipes have being carrying a different type of old gas it furs up the pipes and a sort of hair forms that carries an oily residue and if you try to put the new type of gas through the old pipes (it was only one of the pipes, I forget if it was the gas or the liquid) it ends up contaminating the new gas (or liquid) which has bad effects.

The only solution seems to be to re-site the new unit so that the completely new pipe runs required can be routed reasonably unobtrusively. Since my fist post I have discovered that I couldn't have used the old route anyway, even if the hoses were super-flexible, because they're not actually in ducts but seem to have been cast into the concrete in some places, presumably when the building was converted from office into residential.

The only good news is that the water drain from the internal unit doesn't need to have a drop on it, at least not initially. In fact the moisture drain can even run vertically up out of the unit. Apparently there are units with a pump that can lift the drain water up to 700mm upwards before it needs to run downhill so that at least gives me far more possibilities for routing the drain unobtrusively, possibly mostly in the ceiling.

- Julian