The manifold is the most important component of any wet underfloor heating system. The pipework from each area of your room converges here, and your hot water is fed from the heat source. Choosing the right underfloor heating manifold is key, and this is a choice that will affect you for many years to come. Installing the manifold can be trying, and if it isn’t installed correctly you will end up dealing with cracks and leaks, both of which will cause your entire system to underperform. Correctly choosing, installing, and maintaining a manifold underfloor heating system is important, so we have compiled this handy guide to help you through what you need to know.
What Is A Manifold?
Manifolds are a vital component of all hydronic underfloor heating systems. They are the connection point between the floor circuits (the underfloor heating pipework) and the heat source, and are the termination point for these circuits. Manifolds circulate heated water from the heating source throughout all of the underfloor circuits, and help to control flow-rates and pressure. If you are also using a mixing unit, the manifold will control the circuit temperature.
What Does A Manifold Do?
The manifold controls the flow of hot water throughout the entire underfloor heating system. This helps to maintain a comfortable and even temperature across your floor, and keeps your home warm and cosy. The manifold is the hub of your heating system, and acts as the central ‘brain’ that connects the supply and return lines.
Every manifold is comprised of a flow manifold, which indicates the flow rate of each loop, and a return manifold. Every loop is fitted with an open/close valve that is controlled by an actuator valve that is controlled by the main thermostat.
Manifolds can be coupled directly to the pumped heat source or used in conjunction with a pump or blender unit. Most manifolds are manufactured from pressed stainless steel, and they all undergo rigourous testing procedures before going on the market. This includes being tested to 6 bar of pressure (for consideration, the typical operating pressure is lower than 3 bar of pressure). While some manifolds include automatic air vents, the standard models come equipped with manual air vents (these can easily be upgraded to automatic).
These are some of the features that you want to look for in a manifold:
- A pump that rotates 90 degrees and has a slim profile that fits easily into the manifold cabinet
- That it is easily transferable from one side to the other without the need to adjust the unit
- Is able to pump longer loops than traditional manifold pump sets+
- A flow temperature gauge incorporated into the flow bar
- A blender valve with a temperature setting range between 25 to 80 degrees
What Are the Components Of A Manifold?
Underfloor heating manifolds are comprised of many different parts. These include:
- Drain Valves and Air Vents – Air valves are located on the ‘flow’ and ‘return’ arms of the manifold. They remove air from the system and ensure that it flows smoothly. The drainage valves do the initial filling and draining.
- Flow Gauges – Flow gauges are mounted to each of the flow arms, and there are one allocated per circuit. These are put into place when the system is installed, and they configure the flow rate of the circuit and provide the heat output. This output is set by the heat losses and floor build up. Your flow gauges are also there to give a visual indication of the floor circuit flow rate.
- Thermometer and Pressure Gauges – A dual-purpose thermometer and pressure gauge is attached directly to the manifold, allowing for accurate control and easy usage.
- The Manifold Mixing Unit – The Mixing Unit is used to blend the water pumped from the heating source and the floor circuits, and helps to maintain the correct temperature for the entire system. It is comprised of 3 components – a lower arm, an upper arm and a circulator.
- The Manifold Isolation Valves – The manifold isolation valves are affixed to mixing unit or manifold arms. They allow for testing of the manifold without affecting any of the primary floor circuits.
- The Commissioning Valves – These valves control the flow of water through each of the floor circuits, which then allows for pressure testing, draining and filling the system. In this process the commissioning caps are replaced with actuators that allow for individual circuit control.
- The Actuator – The actuator is attached to the manifold’s commissioning valves, and help to open and close every circuit, enabling the water to flow effectively through the entire system.
- The Wiring Centre – The wiring centre is responsible for controlling and maintaining all of the electrical aspects of your underfloor heating system. It works by making a connection between the manifold, the heat source, and the thermostat.
How Much Does A Manifold Cost?
Manifolds come in a range of prices and models, and the cost will depend on how many ports you require. Underfloor Heating Trade Supplies has everything that you need at very competitive prices. All of their underfloor heating manifolds have been fully approved by the Water Regulations Advisory Scheme (WRAS).
Prices will differ between suppliers, but our manifolds run from £95 (£114 inc. tax) to £265 (£318 inc. tax depending on the number of ports on the manifold. You can browse our manifold prices here.
Summary
The manifold is a vital component of any underfloor heating system, allowing you to maintain temperature and water flow. Choosing the right model will help your underfloor heating system perform to its highest capability, and last for a long time without issue.
