Drip noise / vinegary smell from Daikin ducted split

(I am not a refrigeration engineer, but am in electronic engineering)

Had a Daikin ducted (FDXS-C) split fitted last year (residential install). Used over summer then not again til a few weeks ago. Noticed that usually on startup has a faint vinegar smell at supply grilles for a while, subsiding to musty. Also if fan is running fast I will often hear a drip... drip... noise transmitted through the grilles. Manipulating the drain line slightly changes this noise (speeds up / slows down), and low-and-behold looking around the attic I can see that the drain line drops 10cm, and then spends around a metre going up-hill, so I guess the drip noise is air bubble moving along the drain line as the standing water in the pipe is displaced?

I've cleaned the unit with RTU evaporator cleaner, and added a stay-clean treatment to the drain pan, which has sorted the smell for now, but I realise I need to sort out the drain really, otherwise I guess it will recur.

So at the moment the drain is made up of the flexible Daikin hose with a 21.5mm coupler inserted, and then 21.5mm pipe going down (and up!) then down again and out into the side of the gutter downpipe outside the house.

From what I read there should really be a trap on the drain, close to the unit, and the pipework should all go downhill. Looking at (mostly US-based?) installations it seems like there should really be a secondary drain pan under the unit too, draining out somewhere visible?

I've bought a 3/4" EZT-150 waterless trap, but I'm stuck at the most basic part really - how is it best to make up the drain pipe sections into the trap and then out of the trap? A quick shufty round B&Q would say that I can't easily find pipe / fittings which are snug into this trap, and then what is best to do at the Daikin unit - modify the flexible hose, or couple something directly to the drain pan outlet?

Or am I barking completely up the wrong tree?

Thanks!!! :)

re do the drain so it has a constant 1 cm per meter fall-maybe oversize it to 1 inch- if this isnt possible then fit a condensate pump and use braided hose to discharge the condensate- this hose needs to run upwards to prevent syphoning-also the outlet needs to be higher than the pump- wire in the alarm contact to stop the power to the indoor-terminal 1 dont break the signal/comms wire

The drain hose is an 'kit' part from Daikin so could be removed from the unit so that you can connect directly, as in the pictures from your EZT150

http://airtec.rectorseal.com/images/ezt150.jpg

If you are having trouble connecting two different size plastics then you might try a McAlpine Coupler, from Plumb Center eg, which is a plastic compression fitting.

Thanks guys for getting back so soon :) half the problem I have is not being in the trade I don't know the lingo for what I need to search for! :) Ideally I would like to connect directly to the Daikin outlet, ommiting the flex hose, so a coupler it is that I need.

Should there be a second drain pan installed under the unit? Or could it be enough to install a float switch into the drain outlet (I think the EZT manufacturer do one that fits into the top of the cross) and have that cut terminal1 on the indoor unit?

I wouldn't suggest putting a flood switch via terminal one as the control wires are normally serial communications and not on/off; extra contacts can mess up the unit and give you more faults.

You shouldn't need an extra drain pan as long as your drain pipe can clear the water.

Thanks. It seems like the American residential installs are more "belt and braces" in their approach - or is this just a function of the units they are putting in being much larger than what might make its way into a UK home?

Not sure on your unit, some ducted units need a trap to drain properly and others don't (depends if drain pan is subject to positive or negative pressure from the fan). In either case if it is not done the way the unit needs it won't drain properly.

Don't think a waterless trap would work but could be wrong. (think it might just be held shut by the negative pressure)

If I disconnect the drain hose I see water and air blown out of the drain, so I guess this means positive pressure?

The EZT waterless trap claims to be suitable for use in either positive or negative pressure applications. Though I don't know in practice if this is true...

The musty/ vinager smell. Is a bacteria build up during winter heating cycle, and gunge build up in ducting and on coils. Hard to get rid of. Stems from people body odour, that smelly bit just below the belly button. Short answer is duct cleaning & sanitizing, carbon activated filters may help. If ducting supply is flexible then install replacement.

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Originally Posted by Magoo

The musty/ vinager smell. Is a bacteria build up during winter heating cycle, and gunge build up in ducting and on coils. Hard to get rid of. Stems from people body odour, that smelly bit just below the belly button. Short answer is duct cleaning & sanitizing, carbon activated filters may help. If ducting supply is flexible then install replacement.

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The smell actually seems to be gone now after a really good dousing of RTU evaporator cleaner and disinfectant, and a shot for DrainKleen from Advanced Engineering, plus put a couple of StayKleen treatments in the drainpan. I bought a bottle of Guardian antimicrobial coil treatment at the same time but haven't applied it yet - what do you guys think about it?

The drain line definitely needs sorting tho so that is my next job. It has so much water standing in it that tonight the pipe was very wet on the outside where the warm attic air is obviously condensing onto the pipe surface. Is it worth insulating the drain line while I'm at it, or is that likely to be surplus to requirements once the drain is running downhill and not collecting standing water?

Quote:

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Originally Posted by monkey spanners

Not sure on your unit, some ducted units need a trap to drain properly and others don't (depends if drain pan is subject to positive or negative pressure from the fan). In either case if it is not done the way the unit needs it won't drain properly.

Don't think a waterless trap would work but could be wrong. (think it might just be held shut by the negative pressure)

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For anyone interested, the EZT-150 waterless trap looks like it works great on this unit. I attached it briefly to the drain outlet using a sealing cord made of bituminous rubber sealing cord (used for uprated water seals on VW group cars) and does indeed allow the water to pass out of it while preventing the air coming out. I really like that it is transparent - I'm a borderline hypochondriac so seeing the drain working will give me no end of confidence.

I'll now get all the pipework bits to plumb it in permanently.