jbs Posted January 6, 2012 Share Posted January 6, 2012 Hi everyone, I was sent a new switch for my compressor to replace the old tired one that kept leaking air, however on looking at the internals of the switch to wire it up I find that it's a tad differently laid out to the previous one and no matter how long I search on either here or even googling it I can't find out how to actually wire it up without electrocuting myself which would obviously spoil my day, So would it be possible for someone to have a look at the photograph below and advise me on whats what on the photograph-the only thing that i do know is that the two lowest screws have the earth symbol next to them as part of the casting on the plastic other than that there is no other marks as such on it Any help will be appreciated TIA John Quote Link to comment Share on other sites More sharing options...
stuck Posted January 6, 2012 Share Posted January 6, 2012 Can't tell from the picture John. Do you have a multimeter? Quote Link to comment Share on other sites More sharing options...
jbs Posted January 6, 2012 Author Share Posted January 6, 2012 I have a multimeter,but am very inexperienced with it, I can measure the basics but am always keen to learn more, Quote Link to comment Share on other sites More sharing options...
stuck Posted January 6, 2012 Share Posted January 6, 2012 Ok John, Get your old switch (assuming it's still working) put your meter on continuity (ohms) and measure the resistance across the two terminals where the wires were connected. The switch should either be normally open ( infinite resistance ) or normally closed ( 0 resistance ) once you have found which it is try to find the same set or terminals on your new switch. Once you have established which terminals you think it should be you should ideally try to get it to change state before the PRV on your compressor lifts. Edit: obviously on a compressor it's uber important that you get this right, can you apply pressure to the switch at work to check it changes state? HTH's Mick. Quote Link to comment Share on other sites More sharing options...
jbs Posted January 6, 2012 Author Share Posted January 6, 2012 Mick, Many thanks, I will try that tomorrow now as it's late and I don't want to annoy my neighbours at this time of night, If anyone else takes a look at the photograph and knows what way it should be wired up then don't be shy and speak up John Quote Link to comment Share on other sites More sharing options...
stuck Posted January 6, 2012 Share Posted January 6, 2012 John, If you don't get any further with it post your location & someone near by may give you a lift. Failing that post it to me & I'll mark it up for you. Quote Link to comment Share on other sites More sharing options...
jbs Posted January 6, 2012 Author Share Posted January 6, 2012 Mick, thats very kind of you-thank you, hopefully when I take a look at it with your directions then all should be come a lot clearer-well I'm hoping it will anyway lol John Quote Link to comment Share on other sites More sharing options...
jbs Posted January 7, 2012 Author Share Posted January 7, 2012 Mick, I followed your instructions and found the following: the far left two screws were for the live(brown cable) the two screws in the middle of the switch were for the negative(blue cable) and the far right was for-well nothing really, The two lowest screws out of all of them were as marked-for the earth, So I'd like to say thank you for your help and unfortunately I now have a new problem with it lol, It when its finished filling the compressor will leak air like mad out of the bottom of the switch itself until it gets to a lower pressure then switches the motor back on and starts all over again, I have tried adjusting the adjuster bolt on top of the switch inside the cover to allow it to build up enough pressure then turn off at a lower pressure but even doing this seems not to have sorted it, and if I adjust it too far the compressors original safety valve will kick in, So either I've got another brand new switch that is U/S or I'm not doing something right-Any ideas anyone? TIA John Quote Link to comment Share on other sites More sharing options...
stuck Posted January 7, 2012 Share Posted January 7, 2012 John, Is it leaking from the body of the switch or from where the switch screws in to the fitting? I guess you mean it's from the switch itself in which case I haven't a bloody clue I'm afraid! Quote Link to comment Share on other sites More sharing options...
jbs Posted January 7, 2012 Author Share Posted January 7, 2012 Mick, It's leaking from the body of the switch right next to where the brass nut is(which is tight by the way) underneath where the two sets of wiring are coming in/out of it-doesn't do it whilst it is filling but will do when it's stopped filling Quote Link to comment Share on other sites More sharing options...
stuck Posted January 7, 2012 Share Posted January 7, 2012 Sorry Sir, Haven't a clue why it's doing that. Quote Link to comment Share on other sites More sharing options...
jbs Posted January 7, 2012 Author Share Posted January 7, 2012 Ok thank you anyway mate Quote Link to comment Share on other sites More sharing options...
jbs Posted January 8, 2012 Author Share Posted January 8, 2012 Mick-I've sorted it!!, turns out that the reason that the air was leaking through the switch was because the Non return valve(NRV) was stuck open, the NRV is a brass fitting where the 15mm copper pipe goes from the compressor head to the actual air reservoir, this is an easy fix to do, all you need to do is bleed off the remaining air-if there is any, remove said copper pipe, unscrew the brass fitting and dismantle it to remove the internals which are, a small low power spring and a round rubber block for a better word to then remove the obstruction, Turns out my one had 4 very tiny pieces of rust from the inside of the cylinder trapped in-between the rubber block type thing and the brass fitting itself hence why when it got up to full pressure of 150 psi it bled air out of the switch like hell, Now before anyone thinks I haven't drained down my cylinder-ever I do this religiously as i know how dangerous it can be with regards to compressors and the possible failure of the cylinder later on down the road Thank you very much for your help, John Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.