Driers on split system pipes

[R1976]

Hi,

I looked at aToshiba 460AH8-P outdoor unit today that had driers on the suction and expansion line brazed in near the unit. I'm assuming they are being used as burnout driers but surely they should have been taken out after a period of time. Could they cause any damage by being left in, no one has looked at this unit for 2 years and not sure who fitted them.

[paul_h]

The one on the expansion line wouldn't be doing much harm. I fitted a lot under warranty after burnout, and if space permitted, even fitted them inside the unit as per manufacturers request as a permanent thing.
The suction one should be removed as it might affect reverse cyle heating, but they normally have schraeder valves to check for pressure drop to see if performance is affected, and should be marked for fit and removal date.
I'd quote the owner for pump down/welding in pipe, evac and get the suction drier taken out if it's been two years.
As far as the expansion line drier, I'd either change it or leave it, no harm in having one there as split systems do not normally have any other type of drier than what someone in the field fits, and like I said, I've fitted a few as permanent fixtures after a burnout.

[nicolacozma]

If that filter are corectly chosen, then they are not harmfull.
In your case, to be sure that the filters are working propperly it`s better to replace it with a new one.
Otherwise you can make an oil quality test. If oil test it`s ok then you can remove this filters.

regards

[monkey spanners]

If its a heatpump, you don't want a drier in what becomes the hot gas pipe in heating mode, as the heat can cause the drier core to break up.

[R1976]

Thanks for the replies,

I think i'll offer a oil test and remove them if it's okay.

[glenn1340]

I have fitted a filter drier to an old Toshiba heat pump. The manufacturer said it had a by pass valve fitted to enable the refrigerant to flow in either direction without removing any debris caught in the filter core. Its been working fine now for a year. I think I`ll leave it until work slackens off and then say it needs removing.

[brunstar]

yeah i would be removing them as they can also act as a liquid reciever if too large causing the expansion valve to open and close premiturly, as paul said if you are going to fit one put it on the common suction to the compressor this is the best practise as it will get all of the crap out of the system in what ever mode and not effect the systems operation due to the drier acting like a reciever.

[R1976]

I went to this site again today and driers are still there. Noticed that drier in bigger pipe is a one way drier and is fitted as if its a suction line. What would happen when in heating mode and refrigerant going in opposing direction?

[monkey spanners]

Any loose crap in there will get blown along the pipe till it hits something it can't get past. Normal driers only have the felt pad and gauze at the outlet side to collect bits of the drier core etc.