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Doosan DNM500 TSC delay


Apr 16, 2015
Hi Everyone,

I have a situation with a Doosan DNM500 mill.

When the thru spindle coolant is commanded on there is a long delay before it actually gets to the tool and starts flowing. It generally varies between 4-10 seconds, but sometimes doesn't come on at all. We have fully cleaned the tank, intake filters, screens etc. I have checked all the hoses for obstructions and found nothing. The bag filter is brand new, the housing is spotless but still the issue persists.

I have narrowed it down to the pump itself, it is running instantly on an M07 command but takes a long time to build pressure if at all.

Has anyone encountered this before? Any suggestions or procedure to take the pump apart?


D Nelson

Jan 7, 2015
Missouri Ida
Sounds like you need a check valve in line. Sounds like it’s loosing its prime. When it starts flowing if you shut it off and emediately restart does it work then?

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