SIP Airmate TN3HP/50-SRB

[rtbcomp]

I've just bought one of these and amongst several issues it keeps blowing the mains fuse when it starts up.

It cuts out OK with a hiss, but on restart there's a 50/50 chance of the fuse blowing. It's rated to run off a 13A socket and came fitted with a 13A plug. If it's going to blow the fuse the 20A MCB in the consumer unit buzzes but doesn't trip, if it's going to start OK there's no buzz.

I did notice that the start capacitor was 100 µF, but the label on the motor states it should be 200 µF, could this be the problem?

 

[rtbcomp]

Adding to the above, if the centrifugal switch in the motor didn't close, would that cause the same problem?

 

[the snooper]

I think I would start with the capacitor, does it start up ok when empty ? if so the centrifugal switch must be ok, also dead capacitors cause the motor to buzz and do nothing else got to be worth a new capacitor if the data plate says 200 uf

 

[rtbcomp]

It seems to start OK when empty, but that may be coincidence

If it's going to fail the motor starts very sluggishly, as if there's residual pressure in the delivery pipe, but there isn't because it stopped with a hiss. If it's going to run OK it starts quite briskly. I'll check that when it fails it always tries to start in the right direction. I reckon a duff cap or switch could cause it to try to start in a random direction.

One thing I have noticed is that the hiss is very brief, unlike my trusty old Clarke, which is fairly drawn out. I suspect the SIP's delivery pipe & aftercooler are smaller to cut down cost, this means the pipe is up to pressure before the motor has reached running speed.

 

[the snooper]

It seems to start OK when empty, but that may be coincidence

If it's going to fail the motor starts very sluggishly, as if there's residual pressure in the delivery pipe, but there isn't because it stopped with a hiss. If it's going to run OK it starts quite briskly. I'll check that when it fails it always tries to start in the right direction. I reckon a duff cap or switch could cause it to try to start in a random direction.

One thing I have noticed is that the hiss is very brief, unlike my trusty old Clarke, which is fairly drawn out. I suspect the SIP's delivery pipe & aftercooler are smaller to cut down cost, this means the pipe is up to pressure before the motor has reached running speed.

but it must have worked ok that way since it was made, if the cap is half the value it should be, it wont have the power to start the motor under load

 

[rtbcomp]

True - but how well was it tested? Are they individually tested or batch tested? It worked fine for me when I first tried it, but yesterday morning it went through 3 fuses, this morning it went through a couple, but it's been fine all day. There's something just on the edge of tolerance somewhere.

I emailed Thorite this morning and I've just had a call from SIP to ring them back, so we'll see.

 

[MoreWellie]

assuming it is secondhand it would be worth changing the oil and cleaning/checking the non return valve that stops the tank pressuring the pump

3hp is marginal on a 13a fuse so anything that makes it worse will blow the fuse or the trip on the machine. I have lost count of the fuses I have changed in the winter and everytime I think about getting another 16a socket put in

 

[rtbcomp]

Brand spanking new.

I've contacted Thorite who I bought it from and they passed me on to SIP who rang me back. I missed the call so am going to ring their service dept later today.

The trip on the machine hasn't operated (I only found it by accident, it's not mentioned in the manual).

I'm inclined to try it on a 16A circuit, but want to get the OK from SIP first.

 

[eil]

Have you put your clamp meter on it to check the current draw, shouldn't need to do all this with a brand spanking new one though.

 

[rtbcomp]

Clamp Meter is the next job.

Had a chat with tech support at SIP - the guy says it should have a 200 µF cap. and he's sending me one.