What blocks driers?

[monkey spanners]

Had a call on friday, system cycling on LP switch.
System has had a recent compressor replacement by another company and has had a leak in one of the two evaporators (now disconnected).

I was called as they suspected another leak and had become disalusioned with their original contractor.

I found the direr (055 :rolleyes:) blocked, replaced with a 164 as pipework was 1/2".

Couldn't blow through it at all! I cut it open with the disc cutter and found the felt pad was grey/black and sticky but also looking like it had crystals/salt on it a bit (will try and take a pic). With the pad removed i could blow through the core ok so it was the pad restricting the flow.

Questions, what do you think blocked it? Do the cores ever block up or is it always the pad?

Cheers Jon

[goshen]

hi :
water will do the job it blocks it hermaticly!!
and possibly using wrong oil in system !!
good luck

[Silhouette]

Hi Monkey Spanners,
I think you may have a waxy substance on the pad/gauze? This comes from the oil being overheated which could also be the reason for the comp failure!! Carry out an oil test and check for non-condensables, condenser cleanliness etc. if the discharge temperature is high find out why and resolve it otherwise it will do the same to the new compressor!
Regards,
Silhouette.

[monkey spanners]

Hi Silhouette,

The system will have been running hot, its a Fabdec DX milk tank/ice builder system with fixed orifices on R22, when there is little milk in the tank or a lot of ice in the ice builder they run with very little suction superheat and do suffer from smashed valves/rods, when there is a lot of load on them they have stupid high dischage superheat, it has a heat recovery tank on there as well and the gauge was up to 85C :eek: when running with no ice.

I was wondering if it was blocked by some of that superseal stuff as the previous company had been called out four times for leaks. Will try and remember to take a picture tomorrow :confused:

Jon

[Grizzly]

Hi Jon.
I think silhouette is nearest with his explanation.

Good Luck anyway.
Grizzly

[Sledge]

I am not familiar with that equipment, but would it be possible to install a TX and maintain constant suction superheat...a TX and a receiver has to be cheaper than recurring smashed compressors and downtime.

[monkey spanners]

Hi Sledge,

Yeah you are right, when i went on a training course at the factory where these milk tanks were made they said even they didn't know why they made them like it :rolleyes:

All the new ones have txv's etc, i think when R22 runs out next year they will have no choice but to change to txv's as there isn't really a drop in for R22 that will run high temp in the milk tank, low temp in the ice builder and cope with fixed orifices.

They usually only throw a rod if they have been run without any milk in the tank as sometimes happens.
I didn't fit the replacement comp so didn't get a chance to see why it failed.

Cheers Grizzly,

I just wondered what blocks them up, i have run a hose through old ones before and they haven't blocked so maybe its always the pad that blocks up and not the drier core.

Cheers Jon

[Magoo]

Why not try a CPR for high load compressor protection. Also I have had driers totally blocked after compressor changes, replaced them with burnout type and fitted suction line type as well ( removed later on ) to totally clean system, will require regular changes.