Low Loss Headers
FlexEJ's range of Low Loss Headers, also known as Hydraulic Separators, covers popular sizes from DN50/200kW to DN150/1,480kW - with larger sizes and multiple circuit designs to order. These robust and cost effective units are manufactured in our UK factory and the following standard sizes are available at direct-buy prices from our web shop on a 24hr despatch basis.
Low LossHeader
Low LossHeader
Low LossHeader
Low LossHeader
Low LossHeader
Low LossHeader
Low Loss Header - Hydraulic Separator
What is a Low Loss Header?
Low Loss Headers decouple the boilers from the system...
- Materials
Carbon steel with PN16 flanges. - Application
Heating water services, boiler arrays. - Rating
10 Barg @ 110°C. - Web Shop
Available online with next day delivery from our web shop.
How to select HVAC system equipment
All these products are designed to protect and optimise your heating or cooling system. These products are normally positioned as follows: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.
A low loss header decouples the boiler from the system. This allows the boilers/boiler circuit flow to optimise at best efficiency for any system conditions. FlexEJ low loss headers come with sensor ports on all four branches so whatever control system is being implemented you will have the port you need.
These separators keep the system clean with both dedicated and combined units. Air causes corrosion and in extreme cases pump cavitation or air locks. Dirt will reduce boiler efficiency over time and will reduce flow areas in all equipment. Removing both air and dirt will keep the system running efficiently and avoid costly maintenance.
Dosing pots are used to safely introduce inhibitors and other chemicals into the flowing system. Maintaining the correct water chemistry ensures all materials in the boilers, chillers and system are protected from corrosion. 
FlexEJ can design and build large, multi-circuit low loss headers to order. We can also offer low loss headers with air and dirt sections and all products in larger diameters for bigger systems. Please let us know what you need.
Call our HVAC specialists on +44 (0) 1384 881188 or email us at sales@flexej.co.uk or use Live Chat on this web site - we are here to help, please get in touch. FlexEJ's Low Loss Headers
Robust and great value for money, FlexEJ's HVAC Low Loss Headers — also known as Hydraulic Separators — are manufactured by us in the UK to our own design. DN50 to DN150 are standard stock and available on a 24hr despatch basis directly from our web shop. Other configurations are available. FlexEJ can also manufacture to meet specific client requirements, please get in touch.
Low Loss Header Applications
The hydraulic separation provided by a low loss header allows multiple pumped circuits to work independently from one another - which is particularly important in achieving the most efficient operation and control of condensing boilers and boiler cascades.
The use of a low loss header is recommended to minimise interaction between primary circuits and the secondary circuits, the primary typically working at a constant flow rate and the secondary at varying flow rate and water temperature.
Features
All products have:
- Rated 10 Barg at 110°C
- Carbon steel body with PN16 flanges
- Flamco AAV with integral shut off valve
- DN25 drain valve
- Temperature probe ports on all connections
- DN50 to DN150 available from stock as standard
- Custom sizes, multiple connection adaptors and specifications
Low Loss Header sizing
The low loss header body is selected to ensure a low flow velocity – and therefore low pressure drop – at full flow rate. Depending on the control method adopted the primary and secondary flow rates may not be equal but often the combined boiler power output is used to size the low loss header.
Standard low loss header designs match a typical flow rate for the connection size to a suitable body diameter and length to achieve good hydraulic performance. The power rating is calculated from the flow rate and temperature difference.
Power rating and flow rate
The power rating quoted is a nominal value based on an assumed flow rate; the low loss header will perform above or below this figure.
The table below shows performance for the FlexEJ Low Loss Headers with a 20°C temperature difference at flow rates typical for the connection sizes. Please contact us for further application assistance.
| Connection | Body Size (DN mm) | Flow Rate (m3/Hr) | Power (kW) | Product code/link |
|---|---|---|---|---|
| DN50-2" | 100mm | 8.6 | 200kW | FEJLLH050 |
| DN65-2½" | 125mm | 13.3 | 310kW | FEJLLH065 |
| DN80-3" | 150mm | 18.9 | 440kW | FEJLLH080 |
| DN100-4" | 200mm | 34.0 | 790kW | FEJLLH100 |
| DN125-5" | 250mm | 52.9 | 1,230kW | FEJLLH125 |
| DN150-6" | 250mm | 63.6 | 1,480kW | FEJLLH150 |
All FlexEJ standard LLH are rated at 10 Barg at 110°C, calculated to PD5500 Category 3 and are SEP category under the PED.
Low Loss Header connection and benefits
We suggest the use of distribution headers or manifold piping on all connections to the low loss header rather than making multiple connections to the LLH body itself.
The low flow velocity in the low loss header body promotes separation of air and dirt from the flow. FlexEJ provide a DN25 ball valve connection for dirt removal and a high quality automatic air vent valve with all low loss headers.
Low Loss Header design and build
FlexEJ has full in-house pressure vessel and buffer vessel design and manufacturing capability. We will be pleased to quote any low loss header size, configuration or buffer vessel you may require.
If you need something even larger or more complex, we will be pleased to engineer and manufacture to your exact specifications - with connections for multiple circuits, integrated air and dirt sections, any diameter or length or any other technical requirements can usually be met, as required.
Custom built or delivered in 24hrs?
You are very welcome to call to talk through your requirements or any technicalities that are concerning you — on +44 (0) 1384 881188 — or please use the Get A Quote form below or order direct at UK factory prices from our low loss header shop pages with 24hr shipping as standard on all stock items.
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.
