Water underfloor heating: installer approval

Approve the pipe and manifold as a combination

Send your installer the proposed parts list and technical drawings. Ask them to approve pipe material, oxygen-barrier performance, outside diameter, wall thickness, temperature and pressure ratings, bend limits and the exact manifold connectors. Matching nominal sizes alone is insufficient. Include seals, adapters, valves and replacement parts in the review.

Approve pump duty, mixing arrangements, manifold flow adjustment, actuator fit and electrical characteristics, thermostat connections and heat-source controls together. Ask for a sample connection using the actual proposed parts. Our component approval guide explains how to record what a sample proves and what remains unchecked.

Approve room heat output before pipe quantities

Ask the heating designer to calculate heat loss for each room using the building fabric, ventilation and intended indoor conditions. Compare that demand with output from the proposed floor system at the intended water temperatures and with the chosen floor covering. A factory coverage claim does not establish whether your rooms will be warm enough.

Approve usable heated area, pipe spacing, circuit lengths, pressure losses, circuit flows and manifold location on a room plan. Include fixed furniture and unheated areas. Check compatibility with the boiler or heat pump and agree any supplementary heating where floor output is insufficient. Record balancing settings and the assumptions behind the design.

Approve the complete floor construction

Have the installer and floor contractor agree a floor section showing the substrate, insulation, moisture-control layers, pipe fixing system, screed or dry panels, adhesive and finish. Check structural suitability, finished height, door clearances, movement joints and protection where pipes cross joints. Agree who supplies each layer.

Obtain the floor-finish supplier’s heating limits and thermal-resistance information, including the underlay. Agree curing, moisture checks and the heating start-up procedure with the screed and flooring suppliers. Freeze the construction in the written product specification; a later change of finish or insulation should trigger a design review.

Agree testing before pipes are concealed

Before ordering, ask the installer to approve a written site pressure-test procedure consistent with the selected system’s instructions. It should state the test medium, pressure, duration, gauge suitability, stabilisation method, acceptance criteria and safe isolation of components. Agree frost precautions and whether pressure is maintained during floor installation. Avoid adopting a generic factory test setting.

Name who witnesses and records the test before concealment, and what prompts retesting after other trades work. Keep circuit identifiers, gauge readings, photographs and signed results. Separately agree flushing, filling, air removal, water treatment, balancing and control checks for handover. Our factory audit guide covers factory capability; a factory check cannot demonstrate the condition of site-installed circuits.

Settle the local approval route and order release

For an England project, check whether building regulations approval is needed before changing the building. Ask the local council’s building-control team to confirm the route for the full scope, including floor alterations, heating connections and electrical work. For projects elsewhere in the UK, confirm the route with the local authority before relying on this England guidance.

In England, an installer registered with a competent person scheme can self-certify work within its scope. Verify that the installer’s registration covers your proposed work. Agree which work they will certify and which needs separate building-control involvement, who handles notifications, and which completion records you will receive.

Release the order only when the installer’s signed approval identifies the parts, drawings, floor construction and test procedure being accepted. Attach outstanding conditions and prohibit substitutions without approval. Name the people responsible for installation, testing, commissioning and handover. Cambridge China Bridge can use this approved pack to brief its staff in China and check the factory’s proposed supply.