Custom Black Steel Manifolds

A black steel manifold is fabricated by welding from seam-welded or seamless black steel pipe and is the most common and most economical distribution component in closed-loop heating and cooling lines. After sandblasting it is protected with an anti-rust primer and a topcoat; Novus Energy manufactures it to project specifications in sizes DN50–DN500.

• Header size: DN50 – DN500
• Header length and branches: project-specific
• Operating temperature: 110 °C for heating lines (closed loop)
• Pressure class: PN 10 – PN 16
• Outlet connection: male thread, female thread, weld end, union, flanged or with valve
• Price: project-specific (quoted to your dimensions)

Design your own manifold → Choose the dimensions, download your A4 technical drawing and get a quote via WhatsApp.

What does a black steel manifold do?

A welded manifold header made from seam-welded or seamless black steel pipe. It is the most common and most economical solution for closed-loop heating and cooling lines; it is protected with primer + topcoat or, on request, with epoxy. The job of the manifold is to receive the flow from the boiler/pump line at a reduced velocity and distribute it evenly to the branches. The larger the header diameter, the lower the velocity, and the lower the pressure loss, noise and imbalance between the branches.

After fabrication the header is sandblasted and finished with an anti-rust primer and a topcoat; the color is chosen on request.

Key features

• The most economical solution for closed-loop heating/cooling
• Pipe available in every diameter and wall thickness
• Fully compatible with welded flange, nipple and socket connections
• Sandblasting + anti-rust primer + topcoat protection

Black steel manifold size and capacity table

The values below are calculated assuming a water velocity of 1.0–1.5 m/s and ΔT = 20 K. If the ΔT of the heating circuit is different, the capacity changes in direct proportion; the final selection is made according to the system design calculation.

How to select the manifold diameter

Selection is made in three steps:

1. Find the total flow rate. For heating: Q (m³/h) = P (kW) / (1.163 × ΔT).
2. Limit the velocity. Aim for 1.0–1.5 m/s in the header: Q = A × v × 3600.
3. Check the cross-section ratio. The header cross-section should be at least 1.5 times the total cross-section of the branches.

Example: a DN150 header is suitable for a flow rate of 63.6 – 95.4 m³/h and, at ΔT = 20 K, a thermal output of 1.48 – 2.22 MW. If you would rather not calculate by hand, the configurator runs the same check automatically with every change and suggests the next size up if needed.

Branches, connections and accessories

Branch sizes: ½" · ¾" · 1" · 1¼" · 1½" · 2" · 2½" · 3" · DN80 – DN150 flanged. Outlet connections are made as male thread, female thread, weld end, union, flanged or with valve; branches of different sizes and types can be combined on the same header. Branch positions are defined by center dimensions measured from the left or right end of the header; if valves, unions or meters are to be fitted, the center-to-center spacing is set to the width of the fitting plus an installation allowance.

Parts added on request: ball/butterfly valves, pressure gauges and thermometer pockets, drain valve, air vent connection, strainer, meter connection union, UPN/galvanized support legs, wall bracket, insulation and labeling.

Manufacturing, testing and delivery

The header and branches are machined to the dimensioned drawing and joined by welding; a leak test is carried out after manufacturing. Surface treatment (blasting, primer, paint or hot-dip galvanizing) is applied according to the material. Delivery time depends on the size, the number of branches and the quantity; lead time and price are given with the quotation, per project.

Where are black steel manifolds used?

boiler rooms · water meter banks · heating–cooling lines · solar thermal installations · housing developments · industrial installations

Other manifold types

The same project may call for a different material: PP-R manifolds · Stainless steel manifolds · Galvanized manifolds · HDPE manifolds. For a comparison and selection criteria, see the manifold selection guide.

Find the manifold type you need

• Heating water manifold — the most economical header for closed-loop heating
• Boiler room manifold — supply and return sets, pump groups
• Cooling (chiller) manifold — fan coil and air handling unit circuits
• Hydraulic separator and riser manifold — flow balancing and riser distribution

Frequently asked questions

Last updated: September 20, 2026 · Prepared by: Novus Energy technical team — manifold manufacturing and metering systems. For size and capacity verification: WhatsApp or +90 216 642 42 66.