Hi everyone I have not posted here before but I have just bought a monster of a compressor that needs TLC. The tank is 280 litres it has 2 pumps with 2 single phase 3hp motors I have heard and seen one pump run but only after letting the air out of the receiver so something is obviously amiss there and the other has no wires to the box. Does anyone know if the the two units are wired to power separately or if they should be tandem also what is likely to be the cause of the motor on the one I have seen work not starting while there is air in the receiver. I have taken a few pics and will post as many as are allowed as I really want to restore this to full working order. Thanks Chris
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rtbcomp
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It looks like each motor has its own pressure switch. This is to enusre the pumps don't stop and start at the same time, to avoid surges in the mains.
Each switch will have a wire direct to the mains then to its associated motor.
If you look inside the switch there should be a screw to adjust the cut-off pressure, maybe yours is set too low.
Each switch will have a wire direct to the mains then to its associated motor.
If you look inside the switch there should be a screw to adjust the cut-off pressure, maybe yours is set too low.
Hi and yes it is the one off of ebay I was the winning bidder and it was all supposed to be running and useable, after hiring a van and driving a 100 miles there I was not best pleased on the outcome. The owner had no idea of how it worked or anything else about it after releasing the air which at least proved it had worked I then managed to get one to start the other one has the top of the switch missing and no mains wire so does anyone know where I could purchase a new switch cover or maybe a whole switch, The price was greatly reduced enough to tempt me as I was already in for van hire and diesel. When I play about with the screw which way increases or decreases. I never got back until early evening so I have only steam cleaned it and left it to dry until tomorrow but finding a place to get parts would be a great help. Many thanks Chris.
slim_boy_fat
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Massive indeed!! Don't like the look of that dodgy wiring on the plug....
They are normally connected right at where the pipework enters the tank there are different types, I would undo the pipework in case they are the in line type that enters the receiver, as the compressor runs it feeds the receiver then when it reaches pressure the switch cuts out the motor and unloads the pipework, it may be that there aren't any fitted or they might be leaking by, which would mean the motor is trying to start against a head pressure.
I understand what you are saying but think it very unlikely that anything would have been taken out as the pipes appear to have not been touched ever. I think will start tomorrow by removing the belts and try to get both motors running and from there I will try the pumps and so on but any advice is gratefully received as I have never had any dealings with compressors apart from switching them on and everything you connect to the line magically works.Thanks Chris
Pressure switches are available from machine mart for about £15.00. Make sure you get the correct type , single or three phase depending on the motors.If that beast IS all working ok it will be nice piece of kit to have. You will be able to run one or both pumps depending on air demand. Compressors are quite simple really !!
I had a piece of luck recently , bought a compressor off ebay described as having a faulty motor so SOR (spares or repair) . As it was 7 miles from where I live I decided to have a punt figuring that I could weigh it in if it was dead. It is a 7.5KW , 3 phase , twin cylinder pump , 150 ltr receiver , so a big old beast. Got it for £10.50 AND , it works fine !!
He must have had a 3 phase supply problem and thought the motor was dead !!
I had a piece of luck recently , bought a compressor off ebay described as having a faulty motor so SOR (spares or repair) . As it was 7 miles from where I live I decided to have a punt figuring that I could weigh it in if it was dead. It is a 7.5KW , 3 phase , twin cylinder pump , 150 ltr receiver , so a big old beast. Got it for £10.50 AND , it works fine !!
He must have had a 3 phase supply problem and thought the motor was dead !!
the snooper
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make sure when you get it running that you adjust the pressure switches so both motors do not start at the same time that way it will draw less start up current
Hi again everyone well today things are becoming more apparent and I am gaining knowledge, lets start with the fact that the compressor is a tandem Airmark Turboair and the company still exists I have spoken to them today and the gent has told me to ring him back on Monday as by then he will have read his mails and looked at the pics, as I already know the beast is 21 years old but its his company and he knows them well he is in Edmonton N London so at least I have hope.
Anyway lets get back to business one motor starts and cuts out when it has filled the 280 ltr tank so then I let some air out not suddenly just a slight opening of one of the feed taps to see if it will start again? Well it tries but doesn’t quite make it and rather than risk it frying I unplug, now someone said that could be adjustment of the pressure switch and told me to undo the air feed to the control switch after it had shut down and if it was letting air by then it would be a faulty control well I took the pipe off and it is definitely not letting any air by as there was still loads in the cylinder, now the way I understand things there should be no more pressure when it is full or empty because of all the complicated gubbins that dictate start up and shut down so why will it run up to full pressure (so I believe gauge does not work) and then fail to start again when the air pressure has dropped.
The second motor apparently has a capacitor missing as all single phase motors should have one, there are 2 loose wires in the connection box that obviously had some purpose but in my ignorance I can only assume that these connections had some use or they would not be there, this motor blows a fuse whenever it is switched on it is a GEC single phase 3hp motor which has been a new addition for whatever reason but apparently it needs a capacitor which is nowhere to be seen.
So fellas does any of this make any sense to anyone, as I am lost. Thanks Chris
Anyway lets get back to business one motor starts and cuts out when it has filled the 280 ltr tank so then I let some air out not suddenly just a slight opening of one of the feed taps to see if it will start again? Well it tries but doesn’t quite make it and rather than risk it frying I unplug, now someone said that could be adjustment of the pressure switch and told me to undo the air feed to the control switch after it had shut down and if it was letting air by then it would be a faulty control well I took the pipe off and it is definitely not letting any air by as there was still loads in the cylinder, now the way I understand things there should be no more pressure when it is full or empty because of all the complicated gubbins that dictate start up and shut down so why will it run up to full pressure (so I believe gauge does not work) and then fail to start again when the air pressure has dropped.
The second motor apparently has a capacitor missing as all single phase motors should have one, there are 2 loose wires in the connection box that obviously had some purpose but in my ignorance I can only assume that these connections had some use or they would not be there, this motor blows a fuse whenever it is switched on it is a GEC single phase 3hp motor which has been a new addition for whatever reason but apparently it needs a capacitor which is nowhere to be seen.
So fellas does any of this make any sense to anyone, as I am lost. Thanks Chris
wyn
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Hello Chris,
The one way valves (non return) will be located around the two red circled areas in the centre of your pic below. They will be just under where the thin pipe connects into the side of the pipework. These little pipes then go back to the black control boxes (other red circled area) and are there to release the built up pressure in the pipe work once the compressor stops. It doesn't take much pressure in the tank to prevent start up if these unloader pipes aren't working. It does sound as if the unloader valve in the black control box isn't working.
It looks a nice bit of kit and shouldn't be too much work to get it going properly.
The one way valves (non return) will be located around the two red circled areas in the centre of your pic below. They will be just under where the thin pipe connects into the side of the pipework. These little pipes then go back to the black control boxes (other red circled area) and are there to release the built up pressure in the pipe work once the compressor stops. It doesn't take much pressure in the tank to prevent start up if these unloader pipes aren't working. It does sound as if the unloader valve in the black control box isn't working.
It looks a nice bit of kit and shouldn't be too much work to get it going properly.
rtbcomp
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You might find some of these pictures useful:
http://www.mig-welding.co.uk/forum/album.php?albumid=900
http://www.mig-welding.co.uk/forum/album.php?albumid=900
Hi WYN and thanks for your reply should I attack this tomorrow and undo those pipes you have circled in the middle or should I bite the bullet and replace the black control box this is unknown ground for me if I should go to the valves in the centre are they replaceable consumables or just likely to be bunged up with crap and want cleaning if it is cleaning any recommendation of cleanser. Thanks Chris
Very helpful thanks do you know of any typical diagrams for the motors to show capacitors and the like control boxes etc because the electrical side of this has been molested, the motor that runs has had the reset button removed and bypassed and the other has as far as I can make out a capacitor missing and the reset button has melted and inoperative, I think I may have to remove that motor and take it to be tested any suggestions where anyone. Many thanks Chris
Hi again everyone I discovered another problem today, there is a water drain plug at the bottom of the cylinder that has a knurled protrusion from it that I assume is to be undone with pliers but the nut this piece is in looked a better proposition to undo thinking there is no air in there so it can drain on its own and I can clean and examine no such luck the nut turns as if it is a stripped thread it does not tighten or loosen but it is airtight is this some type of weird and wonderful gizmo thing I have never come across or more to the point is it a stripped thread and I am just lucky it is airtight, but whatever it is, it is something I need to remedy as I am sure there is excess water in the cylinder having seen it when opening the tap to let the air out to restart. Who said compressors were simple I beg to differ. Many thanks everyone Chris
