20 microns is just fine for the 1400. This is about normal for a pump in good condition, but used. I assume you have fresh belt drive pump oil in your pump and have changed it a couple of times since you bought or obtained it.
Without a complete break down and rebuild, all newly acquired, used pumps should have a minimum of 3 changes of oil to purge the old garabge out.
I use Lesker TKO-FF flushing fluid on all my new, used acquisitions for 3 pump downs and changes before ever putting in clean pump oil. I buy my oil and flushing fluid in 5 gallon pails from Lesker.
I really like their TKO-77 pump fluid which is only $45.00 for 5 gallons. It is very viscous, and slow turning Welch belt drive pumps really work well with it. IMHO it gives a slightly lower pressure in older pumps.
I have given instructions on purging old pumps in the past on the old BBS.
Richard Hull
Created on Tuesday, March 27, 2001 11:02 AM EDT by Richard Hull