slow starting Compressor

[turningtim]

Ive got a 3hp 14cu\min compressor works brilliantly in the summer, like now but is a sod to run in winter, takes several minutes to get up to speed and takes an awful lot of current till the motor swaps onto the running windings, enough to pop the overload. It only happpens in winter\cold so I drained and swapped the oil for fresh and topped up the the marked "MAX" once started its fine and even restarts well the same day, so any one got any suggestions??

 

[ColJack]

did you drain it while it was hot?
did you de-gunk it ( like with cars, you put an additive in and run it to thin the oil and bust up the thick sludge to get it all out )
what oil are you using? compressor oil is a lot thinner than car oil..which is why it would run better when warm as the viscosity of the oil is lower..

 

[turningtim]

Yup it was drained hot and re-filled with Clarke (Machine Mart) "compressor" oil so it should be the right stuff, there shouldn't be much gunk its only used domestically averages a couple of hours a week I'd guess not 9-5 five days a week industrially would it be worth getting it hot and draining and re-filling again?

 

[sparkiedave]

The other possibility, does the pressure relief valve work? when it get's up to pressure and cuts out, you should hear a hiss as the air between the pump and tank is released, this is so that when the pump starts again it doesn't start under full load, when it starts again the first half turn or so will have no back pressure to work against, I've got a couple of compressors that haven't had oil changes for years and still work fine, but then they are not made by Clarke ,
(used to sell tools, hated Clarke stuff!!)