HIGH-QUALITY LOW LOSS HEADERS FOR OPTIMISING SYSTEM EFFICIENCY

UK designed and built by FlexEJ for optimal boiler room efficiency and direct value.

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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.

PRODUCT GUIDES

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


1 What goes where?2 Low Loss Headers3 Air & Dirt Separators4 Dosing Pots5 Need something a bit different?6 Let us help
HVAC systems helpAll 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.
HVAC Low Loss HeadersA 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.
HVAC Air & Dirt SeparatorsThese 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.
HVAC Dosing PotsDosing 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.
HVAC something differentFlexEJ 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.
Let FlexEJ help 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.

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 low loss header configuration 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 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.

Low Loss Headers

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.

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.

Frequently Asked Questions


Q. Does a Low Loss Header work as an air and dirt separator?
A. Yes, to some extent, as the flow velocity in the body is low. We provide a Flamco AAV and DN25 drain valve on all FlexEJ low loss headers. However, separation is not as efficient as using a dedicated air/dirt separator as the main low velocity section in the LLH is bounded by turbulent cross flows.
Q. Should a horizontal manifold be used to connect to the Low Loss Header?
A. Opinions vary but ideally all the primary circuit and secondary circuit flow and returns should be brought together in horizontal manifolds before connection to the low loss header.
Q. Where do the primary and secondary circuits connect to a Low Loss Header?
A. On a vertical low loss header the returns connect at the bottom and the flows at the top. If the connections are staggered side to side then the lower pair are normally the primary side.
Q. What size Low Loss Header do I need?
A. Sizing can be expressed in terms of flow rate or power. In heating systems, the total boiler power in the primary circuit is often taken as the sizing criteria. The power rating is directly proportional to the flow rate and temperature difference as given by m.Cp.Δt – Power (kW) = Mass flow rate (kg/s) * Specific Heat of Water (kJ/kg°K) * Temperature difference (°K). Our product table above shows both nominal flow rate and power ratings.
Q. Is there a Low Loss Header calculation?
A. We have a calculator set up, please get in touch with the details of your system and we will be pleased to help.
Q. How is a Low Loss Header designed?
A. Based on the flow rate through the low loss header the body is sized to achieve a very low flow velocity – typically less than 0.3m/s. This low velocity ensures a low pressure drop between flow and return.
Q. Is a Hydraulic Separator the same as a Low Loss Header?
A. Yes – strictly speaking hydraulic separation between circuits is achieved using a low loss header.
Q. What is a Low Loss Header?
A. A low loss header (LLH) provides hydraulic separation between multiple pumped circuits. This allows each circuit to operate independently and to be controlled for optimum efficiency. The header presents very low pressure drop bypass between the flow and return. FlexEJ low loss headers are provided with sensor ports on all four branches so whatever control system is being implemented you will have the port you need.
Q. How do you identify flanges?
A. Our Flange Finder contains details for many common flanges. Typically, to be able to make the identification you need to know the bore size or outside diameter and number of bolts. For technical assistance contact us or use our Live Chat facility.

Please visit our full FAQ page to see all our frequently asked questions.

Can't quite find the right bellow?

Try the FlexEJ Bellows Finder

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.

Call Us

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.













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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.
FlexEJ Industry Experience