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Water quality and indications for HG series

What water to use for LNI H2 generators (HG series), and how to confirm the water quality in the tank is okay

H2 generators using PEM cell technology require very pure water to operate effectively and reliably over their lifetime. Lower quality water will reduce the operational lifetime of the PEM cell and increase the risk of errors and failures.

Whilst these impacts are typically long-term, using tap water for even a short time can cause the PEM cell to fail extremely quickly, or cause the generator to report other failures.

TIP: If you are unsure, please contact support@uvison.com with your generator's M/N (xxxx-xxxx-xxxx) to seek advice.

FAQs

  1. What water quality should I be using?

  2. How can I check the water quality & conductivity values?

  3. What should my HG series show for water quality & conductivity?

  4. What should I do if my conductivity or water quality aren't within specification?

  5. Where can I find the manual for my generator?

What water quality should I be using?

The water must meet or exceed all of the following criteria:

  •  Deionised water

  • ASTM Type II

  • Conductivity <1.0 μS/cm (<0.1 μS/cm for optimal performance)

TIP: ASTM Type I water has a conductivity specification of <0.1 μS/cm, so purchasing Type I is an easier way of ensuring the water will meet the recommended specifications.

TIP: Use water directly from a demineraliser system, which usually supply 18.5 MΩ (<0.05 μS/cm). The LNI WP series demineralisers can be plumbed directly into any HG BASIC or HG PRO to avoid any cross-contamination risks!

WARNING: Only use a clean, freshly-rinsed out vessel to transfer water from source to generator, if you cannot refill directly from the source.

How can I check the water quality & conductivity values?

The water quality (WQ) value is displayed on the front screen of all generators. It shows as a green bar on the right of the three indicators (H2 flow, water tank level, water quality), which is filled green for 100% and empty for 0%.

The water conductivity is displayed in the Quick Menu (swipe left/right from the main screen). To access the water conductivity (and water quality value) for the HG MINI, refer to the manual.

What should my HG series show for water quality & conductivity?

NOTE: The conductivity sensor in the HG series tank is there for information purposes only - it is not a high-precision conductivity meter so the readings given are indications of water quality, rather than an absolute!

NOTE: The HG MINI values may report slightly higher due to the innovative tank-on-cell design. A value of 2.0-3.0 μS/cm can be normal. 

Conductivity values:

  • < 1.0 μS/cm is recommended

  • 1.0-1.5 μS/cm is okay

  • 1.5-2.5 μS/cm is not ideal, but shouldn't cause any lasting damage

  • >2.5 μS/cm is not recommended and steps should be taken to try and improve water quality

Water quality scale:

The acceptable range for the water quality is 90-100%.

What should I do if my conductivity or water quality aren't within specification?

CAUTION: If the deioniser filter is due for replacement, do that & check if it solves the issue before doing any further troubleshooting.

CAUTION: Confirm the water source is suitable, and any transport vessels haven't been contaminated before doing any further troubleshooting.

Steps to try if the water filter isn't due for replacement, and the expectation is that the water quality in the tank should be okay:

  1. (For HG MINI, skip to step 2) Run the generator in "Start Close" mode for 1 hour. If the conductivity doesn't come down:
  2. Drain the tank following the operating manual, and fill tank with fresh water to ~90%. Repeat 3x. If the conductivity doesn't come down:
  3. Replace deioniser cartridge and repeat step 1 for a few minutes.

WARNING: If the conductivity is significantly above 2.5 μS/cm, or the system has been off for more than 2-3 months, it's better to not run in "Start Close"!

Instead, it's better to force the generator to circulate water through the filter without applying power to the PEM cell:

Make sure the generator is stopped and the deioniser filter is connected, and run the "Drain water with pump" function [Menu → Water tank → Drain water with pump] for up to 1 hour.  As long as the filter is connected, this will not actually drain the tank.

If the conductivity doesn't come down, move to step 2.

If the conductivity still doesn't drop, or is sitting at a significantly-different value to "normal", please contact support@uvison.com with your generator's M/N (xxxx-xxxx-xxxx).

Where can I find the manual for my generator?

Click here for information on locating the latest manual for your LNI generator.