Solved: Partially Plugged Archon Water Heater Assembly

[LALman]

I have an OI Analytical Archon 4552 autosampler and the Agilent DY50559690 Archon Water Heater Assembly seems to be partially plugged. Nitrogen goes through but water at only 20 psi from the water reservoir does not. Has anyone had success with trying to clean the water path? Is there anything except methanol which could be used as a cleaning solvent without creating an unending contamination source?

[LALman]

Update:
I have hooked the unit up to my Dionex 2000 HPLC pump. I can pump 3.00mL/min through the line at ~420 psi. Its hard to figure how the previous user got this line clogged. Its supposed to have DI water. But might it be a good idea to pump dilute acid (Hydrochloric, Nitric, or Sulfuric) through the unit to remove possible scale?

[LALman]

Update:
I have hooked the unit up to my Dionex 2000 HPLC pump. I can pump 3.00mL/min through the line at ~420 psi. Its hard to figure how the previous user got this line clogged. Its supposed to have DI water. But might it be a good idea to pump dilute acid (Hydrochloric, Nitric, or Sulfuric) through the unit to remove possible scale?

We made 50mL of a solution of 4% V/V Nitric acid with ~8% MeOH.

e.g. Added 10 mL water to a 50mL centrifuge tube, added 2mL concentrated Trace HNO3, filled to 50mL line with premade 10% MeOH reagent.

We used the HPLC to pump this at 3mL/min through the Archon Water Heater assembly at 3mL/min. Lots of fizzing, pressure dropped after 20mL to less than 125psi. Added in a pressure loop and pumped all 40mL through. Then re-primed pump with DI Water and pumped DI water through the Archon Water Heater at 3mL/min for an hour. After that re-plumbed the Dionex 2000 system and put it on to run for a couple hours. It was at baseline within minutes.

Reinstalled the Water Heater Assembly into the Archon 4552. Ran ten 20mL flushes in a row without any problem. Apparently the plugging was due to calcium carbonate. But did not analyze waste for calcium. I'm guessing someone tried to run a carbonate buffer as dilution water and it scaled out in the Archon Water Heater.