fault on ingersoll rand dryer

[paul441]

Hi guys
Got a ingersoll rand dryer with compressor constant running and very hot , thought it was short of gas (r407c) so reclaimed and got 1.7kg should have 2.4kg tried to put new charge in but unit only pulling in 1.8kg wont take any more and comp doing same.
I think comp has gone its not pumping 100% piston failure would i be right to think this, complaint is water down lines on compressed air unit.
any help grateful , cheers

[DTLarca]

Hi guys
Got a ingersoll rand dryer with compressor constant running and very hot , thought it was short of gas (r407c) so reclaimed and got 1.7kg should have 2.4kg tried to put new charge in but unit only pulling in 1.8kg wont take any more and comp doing same.
I think comp has gone its not pumping 100% piston failure would i be right to think this, complaint is water down lines on compressed air unit.
any help grateful , cheers

What do you mean it won't take any more?
Are the condensate water blow-down valves clear and operating?

[sedgy]

hi paul ,
you said you got 1.7 kg of gas out of the system , did you vac out? I take it you pressure tested? how much water did you get out ?
you say the comp, is running very hot, is there any water in it? sedgy

[glenn1340]

If it`s not got the correct charge that could account for the comp running hot. Don`t rely on the pump pulling in the refrigerant, you`ll need to heat the cylinder with a heat band in this weather to raise the pressure (you`ll be charging as a luquid of course). As DT asks, check the condensate drains. If they`re the Domnick Hunter electronic level detector type they could be faulty (check for a green flashing LED on the drain body, it shows it`s trying to clean itself but it rarely works).
Oh, best to check that some numpty`s not opened the bypass, I`ve lost count how many times I`ve gone site only to find the dryer bypassed

[martinw58]

if the unit has hot gas valve keeping suction pressure higher than cylinder pressure you may need to lower pressure or increase cylinder pressure did you find leak to account for short of gas

[paul441]

Hi Martin
Did check and found no leak also drain ok and hot bypass valve ok, the unit is a free standing dryer. comp very hot and running constant just thinking it not pumping 100%,what do u think

[chemi-cool]

Hi Martin
Did check and found no leak also drain ok and hot bypass valve ok, the unit is a free standing dryer. comp very hot and running constant just thinking it not pumping 100%,what do u think

Close the suction valve and check if the compressor holds the pressure. If not, replace it.

All driers with HGBP run constantly. did you check the heat exchanger for a leak? It can happened and refrigerant goes into the compressed air system, can be checked easily by holding your leak detector if the air stream.
What component operates the HGBP? Is it a pressure control?

[glenn1340]

Hi Martin
Did check and found no leak also drain ok and hot bypass valve ok, the unit is a free standing dryer. comp very hot and running constant just thinking it not pumping 100%,what do u think

Just been thinking about this, if the dryers in a very cold (and where isn`t at the moment!) and maybe draughty environment the HGBV will try to keep the low pressure from dropping to low by shunting HP gas into the LP side . This will, of course, be hot and as the compressor is cooled by the suction gas it can run very hot if the HGBV is over compensating for very low suction pressure. I`ve had several cases of the compressor cooking itself because of this
Try blocking the condensor with cardboard and see how it goes.

[DTLarca]

Just been thinking about this, if the dryers in a very cold (and where isn`t at the moment!) and maybe draughty environment the HGBV will try to keep the low pressure from dropping to low by shunting HP gas into the LP side . This will, of course, be hot and as the compressor is cooled by the suction gas it can run very hot if the HGBV is over compensating for very low suction pressure. I`ve had several cases of the compressor cooking itself because of this
Try blocking the condensor with cardboard and see how it goes.

Hot Gas Bypass must always always always always be installed with head pressure control. Otherwise in low ambients your evaporator will become a heater and you will be relying on the load medium's coolth to pre-cool the hotgas before it hits the compressor.

[DTLarca]

Hot Gas Bypass must always always always always be installed with head pressure control.

Just to clarify what I meant - head pressure control is required purely to maintain TEV capacity. When installing head pressure control we of course do not also need to install hot gas bypass. But when we need to install hot gas bypass then we must be sure to maintain TEV capacity thus we must also install head pressure control when installing hot gas bypass - always.

[paul441]

Thanks for reply guys , i am very grateful for your help.


cheers.