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REFCOM · F-Gas Certified
Manifold & Controls Specialists

UFH Manifold Repair, Balancing & Replacement

Manifold, flow meter, actuator, pump, mixing valve, wiring centre and thermostat work for wet underfloor heating across London and the M25. £120+VAT per hour, parts quoted in writing, same-day slots available.

Manifold & controls work we carry out

This page covers manifold, pump, valve and control component faults. For floor-level problems such as cold spots, pipe leaks and system flushing, see our underfloor heating repair London page.

Manifold repair & diagnostics

Our engineers strip, test and rebuild underfloor heating manifolds on site. We pressure test each loop, check flow and return temperatures, inspect unions and O-rings and identify whether the fault sits in the manifold body, the flow meters, the actuators or the wiring centre feeding them. Full manifold diagnostics are completed in the first visit wherever possible so you get a written repair price the same day.

  • Loop-by-loop pressure testing
  • Flow and return temperature logging
  • Union, O-ring and isolation valve inspection
  • Written fault report with photos

Manifold replacement

When a manifold body is corroded, cracked or made from discontinued components, manifold replacement is the reliable fix. We supply and fit stainless steel manifolds from Polypipe, Rehau, Uponor, Wunda and Emmeti, transfer your existing loops across, re-label every circuit, refill, purge and rebalance the system before handover.

  • Stainless steel manifold supply and fit
  • Loop transfer with full circuit labelling
  • System refill, purge and rebalance
  • Upgraded isolation valves and filling loop

Manifold leaking

A leaking manifold usually drips from a compression union, a failed flow meter O-ring, the actuator seat or the air vent. We trace the exact leak point, isolate the affected circuit so the rest of the floor keeps running, and replace the failed component rather than the whole manifold where the body is sound. Persistent pressure loss after a repair is re-tested before we leave.

  • Leak trace on unions, flow meters and actuator seats
  • Single-circuit isolation to keep heating on
  • Component-level repair before replacement
  • Post-repair pressure hold test

Manifold balancing

Uneven rooms are usually a balancing problem, not a boiler problem. We calculate the required flow rate for each circuit from its loop length and floor construction, then set every flow meter to match, adjust the blending valve temperature and re-check the room-by-room performance once the screed has come up to temperature.

  • Flow rate calculated per circuit length
  • Flow meter setting across all zones
  • Blending valve temperature optimisation
  • Room-by-room temperature verification

Flow meter replacement

Flow meters seize, cloud over or leak at the sight glass, which makes balancing impossible. We replace individual flow meters on most manifold brands without draining the whole system, then reset the flow rates so every loop delivers its designed output.

  • Single flow meter swap without full drain-down
  • Matched replacements for Polypipe, Rehau, Uponor and Wunda
  • Flow rates reset after fitting

Actuator replacement & actuator not working

A thermal actuator that has failed open leaves a room permanently hot; failed closed leaves it cold. We test the 230V or 24V supply at the wiring centre, confirm whether the fault is the actuator head or the control signal reaching it, and fit replacement actuators to match your existing manifold thread.

  • 230V and 24V actuator testing
  • Wiring centre signal verification
  • Correct thread and voltage replacements
  • Zone re-mapped and labelled after fitting

Pump replacement & pump not working

If the circulating pump has stopped, the floor goes cold even though the boiler fires. We check the pump for seizure, airlocks, failed capacitors and dead electrical supply, free a stuck impeller where possible and fit a replacement pump (Grundfos, Wilo or the manifold manufacturer equivalent) when the motor has failed.

  • Pump seizure, airlock and electrical fault testing
  • Grundfos and Wilo replacement pumps
  • Speed setting matched to loop resistance
  • System purged after pump change

Mixing valve replacement & blending valve repair

The mixing valve blends hot boiler water down to the 35-55°C your floor is designed for. A stuck thermostatic head sends water in far too hot — risking floor damage — or far too cool. We service or replace the blending valve, recalibrate the set temperature and confirm the flow temperature with a calibrated probe.

  • Thermostatic blending valve service or replacement
  • Set-point recalibration to floor construction
  • Calibrated flow temperature verification
  • Overheat and floor damage risk check

Wiring centre replacement & repair

The wiring centre links thermostats, actuators, pump and boiler. Loose terminals, failed relays and miswired zones cause heating that runs constantly or not at all. We repair and re-terminate existing centres and carry out Heatmiser wiring centre replacement where the unit itself has failed, including Heatmiser thermostat repair and re-pairing of wireless stats after the swap.

  • Relay, terminal and pump/boiler switching faults
  • Heatmiser wiring centre replacement
  • Heatmiser thermostat repair and re-pairing
  • Zone mapping tested and documented

Thermostat replacement & thermostat not working

A thermostat that shows no display, will not call for heat or has lost its wireless link stops its zone working entirely. We test the stat, its backplate wiring and the signal path to the wiring centre, then replace or reprogram it — including smart and wireless models from Heatmiser, Warmup, Nuheat and Polypipe.

  • Blank, unresponsive and uncalibrated stats
  • Wireless pairing and signal faults
  • Smart thermostat setup and scheduling
  • Backplate wiring corrections

Zone faults — one underfloor heating zone not working

When one underfloor heating zone is not working and the rest of the floor is fine, the cause is nearly always at the manifold: a failed actuator, a closed flow meter, an airlocked loop or a zone that was never wired correctly. Our zone repair visit works through each of these in order and restores the affected circuit.

  • Single cold zone fault finding
  • Airlocked loop purging
  • Zone wiring correction at the wiring centre
  • Loop flushed where blocked with debris

Manifold, pump or thermostat fault?

Tell us what the floor is doing and we will book an engineer with the right parts on the van.

Call 07427 826446

Frequently Asked Questions