Sep. 28, 2026
The manifold is where most underfloor heating mistakes begin
Pipe gets all the attention. The manifold is what decides whether the system actually works as designed — and the first decision on it is the outlet count.
What the manifold actually does
RITABLE's manifold documentation identifies four functions, and a system that is missing any one of them runs effectively open-loop — it heats, but it cannot be tuned:
Distribution — splits flow from the heat source (boiler or heat pump) to the various zones or loops.
Control — valves or actuators regulate flow to each zone, enabling individual room temperature control and zoning.
Balancing — flow meters or flow regulators equalise flow between zones, so each area receives the heat it needs. This is what makes comfort and energy efficiency possible at the same time.
Monitoring — temperature gauges or sensors show the water temperature entering and leaving each zone, which is the first thing to look at when troubleshooting.
One outlet = one loop
Outlet count is not chosen from the size of the building. It follows the loop count — and loop count follows heat demand, floor area and pipe spacing.
Four things drive it:
Heat demand per room. A room with high losses — large glazing, exposed external walls — needs more pipe per square metre than an internal room of the same area.
Pipe spacing. Tighter spacing means more pipe, which means shorter loops for the same floor area.
Practical loop length. Very long loops raise pressure drop, demand more pump head, and heat unevenly because the water has already given up heat by the time it reaches the return. Keeping loops comparable in length is what makes balancing possible at all.
Zoning requirement. Any room that must be controlled independently needs its own loop — and therefore its own outlet.
The working rule: one manifold outlet per loop, plus spare capacity if there is any realistic prospect of extending the system later.
The RITABLE manifold range
Brass manifolds JA-B1 and JA-B2 are available in 1/2", 3/4" and 1" connection sizes.
For floors requiring more than eight loops, the standard approach is multiple manifolds — each positioned to keep pipe runs short — rather than one oversized unit. A single large manifold forces long pipe runs to the far corner of the building, which is exactly the pressure-drop problem the loop limit exists to avoid.
Do not forget the components around it
From the same product range:
Brass air vent — 1/2", 3/4". Trapped air is the single most common reason one loop stays cold while the rest of the floor heats.
Brass ball valve — 1". Lets you isolate the manifold for servicing without draining the whole system.
Brass adaptor — 1". Correct transition between manifold and distribution pipework.
Bend support — protects the pipe at tight changes of direction, where the wall is thinnest.
Floor heating module — for structured, repeatable installation.
A sizing checklist
How many rooms or zones need independent control?
Heat demand per room → pipe spacing → loop length.
Are loop lengths comparable enough that balancing will actually work?
Total loop count = manifold outlet count.
Add spare outlets where future extension is realistic.
Confirm the manifold connection size matches your pipework and adaptors.
Budget the air vent, isolation valve and bend supports from the start — not as an afterthought.
Conclusion
Get the loop count right and the manifold selection almost makes itself. Get it wrong, and no amount of balancing at the manifold will fix a system where the loops were never comparable to begin with.
View the manifold range — or tell our engineers the zone layout and we will help you size it.
