Sealey trips out

[Cret]

Cheers for the thought. That's the issue though. If I was in the UK it would have been back & fixed by Sealey ages ago by now, or replaced.

Again, this may be entirely subjective because I want to believe it (I know how my mind works!) it seems more 'eager' to start now if that doesn't seem daft.

I do have my clamp meter now also, so I think there were current draw tests I needed to do as well. Not 100% certain on the correct process for those as I'm not used to testing current at all, just usually volts or ohms.

 

[brightspark]

Cheers. I actually fitted the new one anyway as I had a vague idea someone had said that previously.

Well, the big question, has it cured all???
No, but it certainly seems to managing a lot more successful starts. Ie out of a dozen or so startups which then were left to run anything from 5-10 seconds or so, it only failed about 3 times. Previously once it refuses to start once, it would tend to continue tripping the overload trip until the tank was drained.

Possibly this is subjective so it's too early to say but it seems to have helped if not cured the issue completely. I'm skeptical though about this I have to say.

I will try to get some use from it and see how it behaves then update on here. Clearly something is not right still, so it may well just be the case that it decided to behave tonight only.

If it turns out still to be crap, I might check the centrifugal switch. Still need to swap out the MCB for a C rated one in case that makes any difference.

May try a lighter oil in case that helps but I've no idea what would be suitable and safe for the machine. Any suggestions?

Also, I may leave it running with the outlet open for a bit to run it in a bit more.

If all else fails, annoying as it may be, I may fit a tap between check valve and unloader so it can begin open, then close once at speed.

Thanks though Sealey for making something so expensive which took me ages to save for, that doesn't even work.

just open the outlet run the compressor for 15 mins till warm then shut outlet and run up to pressure empty and restart. if alls well its on the borderline power wise for running in cold weather .make sure the breaker in supply is big enough as well .if not ok ring the firm up and complain for a replacement or get it fixed at there expense . i dont know if its been said but check the voltage to comp when its starting

 

[Cret]

Thanks - that's the sort of thing I want to try. Although it usually is fine when empty anyway.

I would have had them take it away already except I'm on the Isle of Man and they want me to get it palleted and packaged up to do that which due to various reasons isn't really practical for me. Plus as things have been tested/replaced/swapped out etc I would not at all be surprised if some companies* would just use that as an excuse to void the warranty anyway, even though the whole reason I'm having to is because it failed in the first place.

Not suggesting Sealey necessarily would.

 

[eil]

If you are starting it and letting it run for 5 to 10 seconds and switching it off and then doing this over and over then you are exceeding the motors duty cycle and is a sure way off ruining the capacitors, single phase motors don't like more than 20 starts per hour. Sealy specifies which oil should be used for your compressor and that is a synthetic type and nothing else. do as suggested by Brightspark and let it have some running in time.

 

[the snooper]

hmm i didnt think new caps would cure it
the comp was too new and too little use to need them replacing,
did you try the compressor today with the old capacitor before fitting the new one for comparrison, also note that the temerature has risen since you first posted this problem

 

[eil]

hmm i didnt think new caps would cure it
the comp was too new and too little use to need them replacing,
did you try the compressor today with the old capacitor before fitting the new one for comparrison, also note that the temerature has risen since you first posted this problem

In fairness the compressor is too new for anything to supposedly fail, but alas there is a fault.

 

[Cret]

Right, this evening I started it (no problem at all - empty tank) and ran for a couple of minutes then turned off and drained the tank. Ran then for a few minutes with outlet open.

Removed the switch/unloader unit (the spare I had) and refitted the original one since it's clearly a more refined and better built unit.

Then started again (no issues again) up to 50psi & stopped.
Restarted ok so I left it to 75psi or so and turned off for tonight.

Not lots of starts but no bother at all. We'll see if it re-starts with the part filled tank or not tomorrow.

Also ordered a C16 MCB

 

[eil]

Turned off at the pressure switch and not at the mains I take it.

 

[Cret]

But of course!

 

[Cret]

Ok - a few more things checked/re-checked.

I had run the compressor for quite a while with the tap open to give it a bit of run time (15 minutes, then another run later on at a bit less - doesn't get very warm of course since no gas compression going on in the head like this). Hasn't helped.

Capacitors don't appear to have helped as some suspected. Fortunately they were cheap and will presumably be handy as spares (assuming I ever have a working machine).

I rang the Sealey support line and the bloke I spoke to was very helpful and patient. I explained all the things tried so far and he said they were all sensible & helpful things for me to have ruled out.

He was reasonably convinced after all this that the issue is the pressure check valve/non return valve. There is a lot of sense to this logic and was my original conclusion, since the issue only happens when there is pressure in the tank, which naturally suggests the problem can only be due to that pressure causing load at startup, and for that to happen it would need the valve to be faulty.

I have already replaced that though with a new one, and after checking it again today all seemed fine inside the valve. If that was faulty I would expect a slight hiss from the machine when off, and a gradual pressure drop too.

He doesn't think it's likely to be motor or capacitor related, but he did suggest it has happened in the past that when an overload breaker/trip has been activated a number of times it's possible that they go bad and are then triggered by a lower current draw than should be the case, due to failure of the bimetallic strip. He said it's not common but has been known to happen. I will check the current draw against the trip when it goes, although it will be tricky to spot what it actually pulls as a brief spike I suppose. He said to test that by sticking the leads in series, prior to the trip.

Motor current draw needs to be tested as well. What's the actual technique for this? As mentioned before I'm certainly used to dealing with volts and ohm, but not really measuring current. Is that probes across the motor terminals and set to max AC current, or something else?

Temperature wise, I explained that it seems a common complaint that "the cold" is stated as the cause for a lot of similar start problems. He said that the compressor should be absolutely fine down to about -5 and that there should be no issues at all with the temperature itself, nor the viscosity of the 5w50 oil used at the sort of temperatures where I'm trying to use it (typically no colder than 10C). He does not believe that's the issue even though he said when it's 'really cold' (ie about -5) the oil temp can potentially make it thick enough to cause the excess current draw needed to activate the trip.

He was going to ask around his associates anyway to see if they have any ideas for when I ring back tomorrow or whenever.

Very helpful but I'm currently not any closer to curing the problem. I agree with him that the fact it's related to tank pressure suggests it's a check valve issue, but after replacing it and being no better off I'm not convinced it's that unless they're just an inherently bad design somehow. As he mentioned and I agreed, if that that was the case he's sure he'd know about it from other complaints by now. Who knows!

Will try checking the motor current draw, level the trip is activated at to see if that clarifies things.

Mega frustrating this, but it's nice to know the people at Sealey are more than happy to discuss it with me at length to try and resolve it. He seemed quite keen for me to end up pleased with it, so at least it's enthusiasm rather than the apathy one often expects when trying for service these days!

 

[the snooper]

to check the current draw at start up you need a clamp meter that is quick enough to register and hold the maximum draw figures on the screen.
you may see it with a standard clamp meter as yours isnt starting so it will draw the max current for a longer period

 

[the snooper]

as for the check valve
if your compressor has pressure in the reciever at start up then the pressure in the delivery pipe will be greater at start up anyway as it has to work harder to open the check valve
when there is no pressure in the reciever then the check valve is only spring operated no back pressure to fight.
also if you have pressure in the reciever and remove the delivery pipe air would escape if the valve was faulty

 

[rtbcomp]

If you do use a clamp meter you clamp it round the live or neutral wire, not the whole cable.

At start up do you get air emitting from the relief valve in the switch? It should close when pressure in the delivery pipe reaches about 20 psi, this gives the motor time to get spinning. This type of relief valve is known as a delayed type.

Some types close immediately the motor is started and a separate valve should be provided to allow pressure to build in the delivery pipe. Mine is in the aftercooler.

If your pressure switch is fitted with wrong type this could stall the motor.

Disconnect the thin tube at the switch, start the compressor and when the motor has been running foe a couple of seconds close off the end of the tube. If it continues to pressurise the tank you could be looking at a faulty relief valve.

 

[tigler]

Just to be clear, have you run it upto full pressure and let the pressure switch stop it yet ? Then have you bled air off until the pressure switch cuts it in again ? If so, what happened ?

 

[Cret]

Cheers chaps - I did some quick youtube self tutoring on the clamp meter use and went out to check it.

Remarkably simple and handy I must say!!

Well, for a few attempts at starting it was stalling and tripping, and according to the clamp meter this was reaching around 60 amps when it tripped!!!
This was with the clamp around the live wire coming into the capacitor enclosure, so the main feed from the switch. Here's a pic to show it:

This was with approx 25 psi in the tank at the time.
After a few attempts it started, and here's a short video of the clamp meter's returned figures from a successful start up. As you can see it peaks around 40amps then settles around 11 ish.

http://s26.photobucket.com/albums/c113/Cret/?action=view&current=IMG_0338.mp4

At start up do you get air emitting from the relief valve in the switch? It should close when pressure in the delivery pipe reaches about 20 psi, this gives the motor time to get spinning. This type of relief valve is known as a delayed type.

Some types close immediately the motor is started and a separate valve should be provided to allow pressure to build in the delivery pipe. Mine is in the aftercooler.

Yes, when the tank is empty, it bleeds a little air from the switch/unloader until it reaches approx 20psi then the valve closes.

Here's the interesting thing though. When the pressure is above this in the tank, at each startup it still does a very brief hiss (1-2 seconds perhaps) then stops, which suggests to me that it uses the valve as a starting easer at every single startup (ie gives it a second or two of air bleed each start to allow the motor to get to speed), but if this was closing a smidge early then it'd cause the motor to struggle.

Does that sound possible? You can probably hear what I mean in that video I suspect - just a brief hiss at start for a moment which then stops.

Also, yes, if I undo say the unloader feed pipe, let it start up with no load against it, then close the pipe with my thumb, or screw it in while running, it continues to run just fine. This is how I know that worst case scenario I can fit a tap to that line to allow easy startup that I can control, but that would be ignoring the actual cause of the problem itself and just bypassing it with a bodge.

Just to be clear, have you run it upto full pressure and let the pressure switch stop it yet ? Then have you bled air off until the pressure switch cuts it in again ? If so, what happened ?

No I don't think I have done. Will try to go and check that shortly. My suspicion though is that it will restart ok when the pressure drops because it's only just run, ie the machine is nice and hot from just having run up to full pressure.
I realise that helps the argument for the issue being temp related but I think there's a distinction between considering ambient temp here and the temp of the machine itself.

 

[rtbcomp]

Here's the interesting thing though. When the pressure is above this in the tank, at each startup it still does a very brief hiss (1-2 seconds perhaps) then stops, which suggests to me that it uses the valve as a starting easer at every single startup (ie gives it a second or two of air bleed each start to allow the motor to get to speed), but if this was closing a smidge early then it'd cause the motor to struggle.

Does that sound possible? You can probably hear what I mean in that video I suspect - just a brief hiss at start for a moment which then stops.


Yes, it gives a shorter hiss when there is pressure in the tank. When the tank is empty the whole lot has to fill up to 20psi. When it's full only the delivery pipe has to reach that pressure.

You can get valves with different time delays (operating pressure). If you do have to bodge it, a better method than a tap would be to fit a T-piece in the thin pipe (or better still, the delivery pipe) and lead this to a small receiver. This means the extra tank will have to reach 20 psi before the valve closes. You will lose all the air in the extra tank when the motor switches off.

 

[tigler]

No I don't think I have done. Will try to go and check that shortly. My suspicion though is that it will restart ok when the pressure drops because it's only just run, ie the machine is nice and hot from just having run up to full pressure.
I realise that helps the argument for the issue being temp related but I think there's a distinction between considering ambient temp here and the temp of the machine itself.

OK, do that but wait until the following day before you bleed off and restart.

 

[Cret]

Ok, will do.

Yes, it gives a shorter hiss when there is pressure in the tank. When the tank is empty the whole lot has to fill up to 20psi. When it's full only the delivery pipe has to reach that pressure.

You can get valves with different time delays (operating pressure). If you do have to bodge it, a better method than a tap would be to fit a T-piece in the thin pipe (or better still, the delivery pipe) and lead this to a small receiver. This means the extra tank will have to reach 20 psi before the valve closes. You will lose all the air in the extra tank when the motor switches off.

Yes, that makes perfect sense and also that's a damn good idea about a second receiver to facilitate this thanks. Would be interesting to see if doing this allowed it to work fine though and if it did indicate the valve is closing prematurely. If it wasn't a big faff, I would fit a pressure gauge on the unloader line to monitor what pressure is reached each time it tries to run.

Obviously I don't want to have to do that and I would WAY rather have it running correctly, but good to have alternative plans since this would be preferable to having to return it due to the hassle involved for me.

Would something like a plastic 'PET' type coke bottle do for this (with suitable sealing at the lid somehow)? They can take a lot of pressure (relatively) are always around the house, and obviously have some volume.

What about the currents I'm seeing on the starts/non starts? Any comment on the figures?

 

[tigler]

My reaction to the start current is that it's high. Might be worth another member with a similar compressor could possibly check their's ?

 

[Cret]

I agree but I have no experience of these things admittedly.
I presume even a cheap meter like this has at least some degree of accuracy.

The circuit overload trip is rated 15amps, the MCB is a C16 type, so I'm kind of surprised that it gets to the likes of 60 amps before the 15 amp trip goes. Even when it starts ok I'm surprised that it gets away with a 40 amp pull without the trip going off.

Be nice to have a wiring diagram of how the capacitors are both wired in with the motor etc and the centrifugal switch etc.

The only other thing that briefly occurred to me was a wire on one of the capacitors (forget which) had a bit of a kink in it near the spade terminal. I wondered if it was possible it's got a broken conductor inside it that touches & makes contact at some times but not others, or just not at all, meaning the capacitor isn't effectively being used in the circuit like it should be?

Tempted to chop an inch or so off the wire and fit a new spade just to rule this out, or at least see if I can check continuity while wiggling the wire etc.