"Roughing, System Pressure Wait" Pumps wont work

This could be any of several things, depending upon whether you have a version one or two 979. Since you have a SD451 roughing pump, I assume you have a version one, the one with fuses in the back instead of circuitbreakers. First, I would check the receptacle on the leak detector, and ensure you have the roughing pump (the one that connects to the side of the leak detector)plugged in to the roughing receptacle. Many people get these switched by mistake. The backing pump attaches from the bottom of the leak detector, the roughing pump to the side.

Next, I would check the system pressure thermocouple. Ohm out between the pins for continuity. If the tc is open, the system pressure will not allow the continuation of the start-up sequence. This is an inexpensive part.

Start there. If that doesn't fix things, call 800 882-7426, option 5, and ask for george (the good-looking one!), and we can explore other options.

This could be any of several things, depending upon whether you have a version one or two 979. Since you have a SD451 roughing pump, I assume you have a version one, the one with fuses in the back instead of circuitbreakers. First, I would check the receptacle on the leak detector, and ensure you have the roughing pump (the one that connects to the side of the leak detector)plugged in to the roughing receptacle. Many people get these switched by mistake. The backing pump attaches from the bottom of the leak detector, the roughing pump to the side.

Next, I would check the system pressure thermocouple. Ohm out between the pins for continuity. If the tc is open, the system pressure will not allow the continuation of the start-up sequence. This is an inexpensive part.

Start there. If that doesn't fix things, call 800 882-7426, option 5, and ask for george (the good-looking one!), and we can explore other options.

The version 2 units will have a black protrusion that sticks out of the back maybe 4 inches, where the power cords plug in. But, otherwise, should not make much difference in your case. Ensure the pumps are in the appropriate receptacles, and then ohm out the test port and system thermocouples. And cross your fingers.

Look in the manual, or call me.

800 882-7426, option 5

Hi George,

I think I have version two.  I have no fuse access on the back where it plugs in.  I have attached three pictures for identification.   Let me know if this changes anything.

Regards,

Keith

Do you know how often these units should be serviced?  Far as I know our unit has not seen any servicing for 15 years.  I started changing out the “leak” unit to keep in current calibration for the last 9 years, but that’s it.

We recently loaned this out to a metal heat treat supplier so that they could pull vacuum on an oven.  They ran the unit for 4 weeks solid.  We got it back and it sounded funny the couple times I used it, now no pumps.  Wondering if they burned something out with the long use.

The pumps are attached correctly, since they are never disconnected.  Not sure where I ohm out the test port and thermal couples.  I do appreciate your help for sure.

Regards,

Keith

Hi George,

Our company President has asked me to get info for sending our unit in to be evaluated and/or fixed.

Where do I start with this?

Need this done ASAP.

Regards,

Keith

Call us at 800 882-7426, option 5, ask for Ken george. Will have a few questions.