[Simonh1959]

We have recently upgraded to a HD machie from our old Powermax and I have been training my guys to use it.
Everything was fine until one of them decided to turn the unit on before refitting the quick-disconnect torch head with the loss of some of my coolant.
Now I know that this was obviously a very stupid thing to do but it has made me think that surely there should be a safety interlock arrangement so that if this sort of thing happens then the pump should not start and therefore prevent the loss of coolant.

[jimcolt]

There is an interlock. The pump will turn on, flow on the return line is then monitored with a flow switch.....if the flow is inadequate for torch cooling the pump will then shut down. With the torch not attached there is no flow on the return line...so it will shut down rather quickly. It does take a few seconds and some coolant will definitely be lost. Usually it only happens once!

Jim Colt Hypertherm

We have recently upgraded to a HD machie from our old Powermax and I have been training my guys to use it.
Everything was fine until one of them decided to turn the unit on before refitting the quick-disconnect torch head with the loss of some of my coolant.
Now I know that this was obviously a very stupid thing to do but it has made me think that surely there should be a safety interlock arrangement so that if this sort of thing happens then the pump should not start and therefore prevent the loss of coolant.

[Simonh1959]

Thanks Jim,

I certainly hope it only happens once!
I have another question, yesterday we were cutting stainless steel with F5 & N2 gases and this morning we needed to cut some mild steel using O2 & Air. However when we went to set the manual gas console we got error 042 which indicates low nitrogen pressure and indeed the pressure had fallen slightly overnight having the cylinder valve turned off.
We tried turning the machine off & then on again to see if we could clear the fault (with the nitrogen still turned off) as it seemed odd that it was looking for nitrogen when the console was set to O2 & Air but we still kept getting the same error. We then turned the nitrogen on and everything was then OK, does this mean that we MUST have nitrogen connected all the time even when only cutting mild steel?