tech level liquid indicators Low Pressure
CONSTRUCTION
Moisture
Indicators feature a hygroscopic element that changes color from green to
yellow depending on the moisture concentration within the refrigeration system.
In these models, the sight glass is embedded directly into the hot‑forged brass
body EN 12420 – CW617N, creating a compact, monolithic structure that minimizes
joints and eliminates additional potential leakage points. A modified PTFE
gasket ensures perfect sealing of the glass across all versions.
Configuration by product series:
- MI..MM / MI..MF series: Body and threaded connections entirely made from hot‑forged brass EN 12420 – CW617N.
- MI..S.. series: Available in multiple configurations. Depending on size, either the entire body or only the sight glass is made from hot‑forged brass EN 12420 – CW617N. Connections are made from copper tubing EN 12735‑1 – Cu‑DHP R290.
- MI..T series: Saddle‑type indicator made from hot‑forged brass EN 12420 – CW617N. An HNBR O‑ring positioned between the upper and lower body ensures sealing when assembled.
By
replacing MI with LI in the product code (LI PLUS, LI, LI HC),
the item becomes a Liquid Indicator — identical to the corresponding MI
model but without the moisture‑sensitive element.
INSTALLATION
During
initial system start‑up, the moisture‑sensitive element may appear yellow due
to exposure to atmospheric humidity or residual moisture inside the circuit.
Once the refrigerant moisture level is stabilized through the dehydrator
filter, the indicator returns to green.
Mounting
orientation is unrestricted: indicators may be installed in any position
required by the system.
APPLICATION
Moisture
and liquid indicators of the MI series are classified as “Pressure
accessories” under PED Directive 2014/68/EU, Article 2, paragraph 5. The
intended refrigerants vary depending on the specific product line, which also
determines the hazard category in accordance with the PED Directive.
According
to Directive 2014/68/EU, hazard classification depends on:
- type of fluid used,
- intrinsic dimensions (DN),
- maximum design working pressure (PS).
Refer to
the technical tables for the hazard category of each specific model, noting
that classification may differ between PLUS, BASIC, and HC
lines.
The entire
product line is engineered for compatibility with nearly all refrigerants
currently used in the HVAC/R sector — specifically, fluids classified under
Article 13, paragraph 1 of PED Directive 2014/68/EU as Group 1 or Group
2. Most of these refrigerants are listed in Annex E of EN 378‑1 as Class
A1, A2L, and A3.
Compatible refrigerants include:
- HFC: R32, R404A, R407C, R410A, R507
- HFO: R1234ze, R1234yf
- HFC/HFO blends: R448A, R449A, R450A, R452A, R452B, R454B, R454C, R513A
- HC: R290, R600, R600a, R1270
In
accordance with Table 6 of Annex II of PED Directive 2014/68/EU, all
products not explicitly excluded fall under Article 4.3 and therefore must
not bear the CE mark, even though they fully comply with the Directive.
All
products also meet the requirements of STATUTORY INSTRUMENTS 2016 No. 1105 –
Pressure Equipment (Safety) Regulations 2016, as amended by the Product
Safety and Metrology etc. (EU Exit) Regulations 2019. Under this
classification, all non‑excluded products fall within Regulation 8 and must
not bear the UKCA mark, even if they comply with the applicable regulatory
provisions.
The entire
product line is suitable for use with fluids classified under Article 13,
paragraph 1 of PED Directive 2014/68/EU as Group 2, meaning non‑toxic,
non‑flammable, and non‑explosive. Most of these refrigerants are listed in
Annex E of EN 378‑1 as Class A1.
Compatible refrigerants include:
- HFC: R134a, R404A, R407C, R410A, R507
- HFC/HFO blends: R448A, R449A, R450A, R452A, R513A
According
to Table 7 of Annex II of PED Directive 2014/68/EU:
- some products are classified as Category I and must bear the CE mark, confirming conformity with the Directive;
- others fall under Article 4.3, and therefore must not bear the CE mark, even though they comply with the Directive.
All
products also meet the requirements of STATUTORY INSTRUMENTS 2016 No. 1105 –
Pressure Equipment (Safety) Regulations 2016, as amended by the Product
Safety and Metrology etc. (EU Exit) Regulations 2019. Under
this classification:
- certain products are designated Category I and must bear the UKCA mark, demonstrating compliance with the cited regulations;
- others fall within Regulation 8 and must not bear the UKCA mark, even if they meet all regulatory requirements.
The entire
product line is designed for use with hydrocarbon refrigerants (HC) available
on the market — fluids classified under Article 13, paragraph 1 of PED
Directive 2014/68/EU as Group 1. These refrigerants are listed in Annex
E of EN 378‑1 as Class A3.
Compatible refrigerants include:
- HC: R290, R600, R600a, R1270
According
to Table 6 of Annex II of PED Directive 2014/68/EU, all products are
classified as Category I and must bear the CE mark, confirming
conformity with the Directive.
All
products also comply with STATUTORY INSTRUMENTS 2016 No. 1105 – Pressure
Equipment (Safety) Regulations 2016, as amended by the Product Safety
and Metrology etc. (EU Exit) Regulations 2019. Under this classification, all
products are designated Category I and must bear the UKCA mark,
demonstrating that their design meets the requirements of the cited
regulations.
