Help with a gah problem

[FREEZER1970]

iv got a customer with a gah rd20 unit,comp had seized,i replaced comp also defective reversing valve,press tested and vac out,new drier,new refrigerant charge,ran and tested unit,running like a dream,now a nightmare after just six weeks,comp has failed again,any ideas anyone.
the driver is a bit of an animal,wondering if this has anything to do with it

[cadwaladr]

did you flush system,what happens is when comp is going faulty the bits{very small}get into system.this is the reason for second failure in my opinion.changing drier will not have been enough,i made a rig years ago its a large capacity replaceable core drier case 7/8ths sweat in and out stepped these down to1/4 flare ,blank off lines at compressor,fill drier casepush the cleansing fluid around system,make sure you get out the same as you put in,wiegh it,vac system,change drier vac again pressure test etc

[tonyhavcr]

Need more info

[The Fox]

what was the condition of the oil in the original comp.?
if it was contaminated did you clean the system?. would guess the system is contaminated, have a look at the oil in the second comp. get the system clean, you can also add a burn out filter to the suction line just to be on the safe side when you return the unit to service..

[cadwaladr]

always change the tev when you have flushed the system,any reason why the original comp failed,best of luck convincing the client,tell him the system was contaminated ,me thinks you may have to waste/absorb the first invoice that is if you are self employed again best of luck.

[SKOOBY]

I would sugest you fit a suction filter in the suction line down near the compressor. Standard practice with Hubbard and GAH.Allso does he run frozen doing a lot of motorway runs if so check engine compressor speeds it may require a low speed kit on the clutch.Many direct drives suffer from this becuase no one checks on instalation

[FREEZER1970]

Thanks for the replies guys,will get the system clean and fit a suction filter,and try again the van runs frozen and chill at the same time and gets hammered to london and back from lincs/norfolk area,wots this about low speed kit on the compressor

[SKOOBY]

If its running frozen on motorways you might find the compressor rpm is to fast.It will spend most of its running in a deep vacuam.Fit your gauges long enough lines and take it for a run allso check comp speed with digital tacho
I will dig some speeds out for you.
If it is overspeeding you need a clutch
low speed kit from Autoclimate.
We had a brand new tk V250 A few years ago seized two comps fitted a kit no more problems.Worth checking

[strattonfridge]

You may find you need to replace the compressor clutch / pulley to allow you to fit a speed reduction ring as the standard factory supplied compressors dont normally need to run a speedc reducing ring. Also how old is the system as recently a large amount of new units have been coming out of the factory with no oil in the system, so it could of been commissioned without any oil being added.

[technode]

You should of had, two can of oil come with it!!!

[technode]

I think this may of changed again !!!

[technode]

iv got a customer with a gah rd20 unit,comp had seized,i replaced comp also defective reversing valve,press tested and vac out,new drier,new refrigerant charge,ran and tested unit,running like a dream,now a nightmare after just six weeks,comp has failed again,any ideas anyone.
the driver is a bit of an animal,wondering if this has anything to do with it

1.Make sure the system is very clean 2.fit a suction filter 3.check the superheat settings 4.make sure you have the right amount oil /and the right grade of oil in the system :D

[djbe]

iv got a customer with a gah rd20 unit,comp had seized,i replaced comp also defective reversing valve,press tested and vac out,new drier,new refrigerant charge,ran and tested unit,running like a dream,now a nightmare after just six weeks,comp has failed again,any ideas anyone.
the driver is a bit of an animal,wondering if this has anything to do with it

I a similar problem. Found that it was running in a vacuum on defrost.

There is a small grub screw in the hot gas return line that gets blocked.

Check it is clear. PM me if you need more info.

Cheers,
Dave.

P.s they don't call them GASH for nothing:rolleyes:

[FREEZER1970]

thanks for your help guys,going to strip and flush out the system,will let u know how it goes

[thermo prince]

If it is overspeeding you need a clutch
low speed kit from Autoclimate.


Hi Skooby, curious about this ... is this an RPM sensor that disengages the electromagnetic clutch once a preset value reached or ....?
Can you send me a link or contact for AutoClima(te)?
Generally in AP we change diameter of crank drive sheave or if space permits use intermediate/transfer pulleys to get the final crankshaft pulley: compressor pulley ratios we need.

Agreed with many of the good replies already - oil type and qty (for TAMA swashplates should be Solest 120 and 180cc per compressor guideline). Generally try to keep them under 3000 rpm (TM's 16,15, regardless what other charts tell). Sanden, Denso and Unicla may have their own guides.
Obvious but with petrol vans, easy to overspeed compared to diesels.Watch that intermittent 'red lining' on acceleration.
Also be wary not to mix PAG glycol oils (from aftermarket, automotive a/c suppliers) with the POE esters that transport are endorsing for HFC404a/134a in refrig applications.
Check and drain out off the shelf replacement compressors if in doubt about PAG or POE inside! Then refill clean from get go!
Deep evac system to 500 microns and get it to hold under 1500 on pressure rise after pump isolation.

thanks and regards
T-P

[Cool Blues]

What was the oil level in the compressor post failure?

Could be an issue with the seperator

[FREEZER1970]

i have flushed the system on this unit,going to fit suction line filter,does it have to be a gah drier,or can i get one from ref wholesaler

[cadwaladr]

i have flushed the system on this unit,going to fit suction line filter,does it have to be a gah drier,or can i get one from ref wholesaler
i swear by sporlan,gah dont make filters,i know the main drier is probly valcon,if you have flushed it 100percent add some oil to the system,and bomb the system with 1kg and keep the revs low to let the oil circulate

[TimSaxon]

hi, out of interest what did you use to flush?

[SKOOBY]

If you are fitting it in the suction line you
can get it fromgah as a kit with the fittings
Did you check comp speed

[FREEZER1970]

i used ak flush,hope its done the trick

[ttb]

These units are overfilled with oil on installation ! Check there is no oil "carry over"
the other main reason is there was not enough oil in system. Once a new unit is fitted, run for a couple of days, then check oil. The compressor ( seltec ?) comes with a standard amount of oil. The longer the hoses the more oil should be added.

[Bond]

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[clivemtk]

go on then show me the grub screw causing the fault

[djbe]

go on then show me the grub screw causing the fault

Firstly my error it's not in the return but in the feed to the evaps.:confused:

If you take the condenser cover off and follow the liquid line outlet from the T flow drier you come to a bracket with an O ring fitting where the defrost hose connects.

Undo that fitting the screw is screwed inside the female fitting. It needs a small Allen key to get it out. It's just a grub screw with a small hole drilled in it.

Regards,
Djbe.

[brass_monkey]

Hi,Let me guess......Sprinter or Crafter??