AIR & DIRT SEPARATORS FOR HVAC HEATING AND COOLING SYSTEMS
UK designed and built by FlexEJ for optimal closed water system efficiency and direct value.

Air & Dirt Separators
FlexEJ Air, Dirt and Air & Dirt Separators can be used in both heating and cooling systems. These robust and cost effective units are manufactured in our UK factory.
Air & Dirt Separators
What is an Air & Dirt Separator?
Air & Dirt Separators are used to remove air bubbles and dirt particles from HVAC piping systems...
- Materials
Carbon steel with PN16 flanges. - Application
Heating water and cooling water services, not suitable for drinking water. - Rating
10 Barg @ 110°C. - Web Shop
Available online with next day delivery from our web shop.
Dirt Separator
Size | Pressure Rating | Specification | In Shop |
---|---|---|---|
DN050-2" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 560 mm | Yes |
DN065-2½" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 560 mm | Yes |
DN080-3" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 710 mm | Yes |
DN100-4" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 710 mm | Yes |
DN125-5" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm, overall height 980 mm | Yes |
DN150-6" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm, overall height 980 mm | Yes |
Air Separator
Size | Pressure Rating | Specification | In Shop |
---|---|---|---|
DN050-2" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 555 mm | Yes |
DN065-2½" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 555 mm | Yes |
DN080-3" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 705 mm | Yes |
DN100-4" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 705 mm | Yes |
DN125-5" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm, overall height 975 mm | Yes |
DN150-6" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm, overall height 975 mm | Yes |
Air and Dirt Separator
Size | Pressure Rating | Specification | In Shop |
---|---|---|---|
DN050-2" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 705 mm | Yes |
DN065-2½" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 350 mm, overall height 705 mm | Yes |
DN080-3" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 855 mm | Yes |
DN100-4" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 460 mm, overall height 855 mm | Yes |
DN125-5" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm overall height 1125 mm | Yes |
DN150-6" | 10 Barg @ 110 ºC | Flanged PN16, installation length nominally 630 mm overall height 1125 mm | Yes |
How to select HVAC system equipment

Air or Air & Dirt Separator ~ boiler flow lines.
Dirt Separator ~ boiler return lines.
Dosing pots ~ main flow and return.
Low Loss Headers ~ between the boilers and system.





Can't see what you want? Need help?
Call us. Or use Live Chat.
For instant advice. We can custom-design and engineer almost any expansion joint you need for delivery in the UK or worldwide. Call our expert team on +44 (0) 1384 881188. Or email us sales@flexej.co.uk
FlexEJ's Air & Dirt Separators:
FlexEJ's manufactures Air, Dirt and combined Air & Dirt Separators in the UK. They can all be bought direct from our web shop on a 24hr dispatch basis (Monday to Thursday). FlexEJ can also manufacture to meet specific client requirements, please get in touch.
Air Separators | Dirt Separators |
Air & Dirt Separators | Custom fabrication options |

Features
All products have:
- Carbon steel body
- PN16 flanges
- DN25 drain ball valve
Air Sections - reduce system corrosion by removing air bubbles:
- Flamco AAV with integral shut-off valve
- Stainless steel internals
Dirt Sections - reduce dirt and sludge build-up:
For further ratings, dimensions and more, please refer the above Range tab, please see our catalogue or range tab above. You can also call/live chat with our expert team.
Got a quick question?
Use Live Chat. Or call us.
For instant advice use the Live Chat link to message one of the sales team. Or call them direct on +44 (0) 1384 881188
Air & Dirt Comparison Chart
Three alternative product configurations to consider plus the option for design and build:
Air separation Air Separation
Is this unit recommended for air removal in UK HVAC heating systems?
Dirt separation Dirt Separation
Is this unit recommended for dirt removal in UK HVAC heating systems?
Air & Dirt separation Air & Dirt Separation
Is this unit recommended for air and dirt removal in UK HVAC heating systems?
Ratings barg/°C Pressure & temperature
What is the required pressure rating (in barg) compared to temperature rating for this bellow?
Not sure what flange spec you need?
Use the FlexEJ Flange Finder to find out
FlexEJ stock a full range of specs and types for our bellows. Or call our expert team on +44 (0) 1384 881188.
Who can you talk to?
Try our sales and customer service team on 01384 881188
They don't bite. And they know what they're talking about. Call the team any time from 9am to 4pm weekdays or use LIVE CHAT if you would prefer a quick text answer. For more complex queries, send us any pro-forma documentation using the get a quote form below or email us sales@flexej.co.uk.
Can't quite find the right bellow?
Try the FlexEJ Bellows Finder
Or call our expert team on +44 (0) 1384 881188
Frequently Asked Questions
Please visit our full FAQ page to see all our frequently asked questions.
Need a detailed quote?
Get A Quote. On us.
We will provide full technical details together with, pricing and shipping timescales. For more complex engineered quotes, preliminary sketches and calculations will be available.
Got a quick question?
Use Live Chat. Or call us.
For instant advice use the Live Chat link to message one of the sales team. Or call them direct on +44 (0) 1384 881188
Get A Quote
Please complete the short form here and we'll get back to you within 24hrs Monday to Friday (quicker if marked urgent).
Alternatively, you can also call our expert team directly on +44 (0) 1384 881 118 from 8:30AM to 4:30PM weekdays who will be only too pleased to talk through your requirements and technical queries over the phone.
Visitors are also welcome Monday to Friday although please get in touch beforehand to let us know you're coming.
Industry experience
FLEXEJ Ltd was formed in 2002 by two professional engineers who brought together an already highly respected design capability with business and commercial skills gained in large multinational companies.
- Our focus has always been on application and design – helping our customers find the best value solution.
- We have a strong engineering and manufacturing team with experience in petrochemicals, refining, nuclear, desalination though to HVAC.
- The team is also very familiar with meeting complex requirements for documentation, in process NDT and test on projects. We have supplied many large end-users such as EDF, Exxon, Shell, Reliance & QatarGas working with major contractors such as JGC, Foster Wheeler & Technip.
