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Rectifying Poor Heatmiser Installation

In this article, I’d like to talk about some of the underfloor heating controls problems we get called out to and the processes we go through to problem solve underfloor heating control issues. We are attending more and more of these underfloor heating controls issue situations: if you are unsure as to whether your underfloor heating controls are functioning correctly, or even at all, then please give us a call.

The video below is an example of the state we sometimes find underfloor heating installations in after a plumber has commissioned the wet side of the system. We are finding that because of the complexity of underfloor heating controls, and it’s integration with existing heating systems, the system is often either left permanently on, or permanently off because the installation engineer does not understand the cabling and connections required to accurately control the system.

Common Underfloor Heating Control Problems

1. Incorrectly labelled heating loops

Your underfloor heating manifold has several heating loops. As the name suggests, when required, hot water is pumped down the flow of a particular loop once the actuator is open, and returns back to the manifold and subsequently the boiler to be reheated. A loop will relate to a particular room, such as utility, lounge, kitchen etc. If a room is over a certain size, there may be two or more loops allocated to heat the larger space.

Often, we will not have been provided with underfloor heating loop diagrams when we attend a property: these have often either not been provided, or have been lost.

Our first job will be to manually fire the boiler, and open each actuator on the manifold one by one, wait for the loop to get hot, and ascertain which loop is heating which area of the house. The manifold can then be accurately labelled.

Underfloor heating manifold, rectifying a poorly installed underfloor heating system

2. Incorrectly wired UH8 wiring centre

The majority of underfloor heating control systems we see are from Heatmiser. These products are pretty bullet-proof providing they are installed correctly. The UH8 wiring centre provides control for each actuator on the UFH manifold, boiler control, pump and zone valve control if required… even a separate hot water cylinder control. They communicate with Heatmiser Neostats, wireless Neoair stats (if using the RF version of the UH8 wiring centre) and Heatmiser hot water programmers to fire the boiler as required. Sometimes the wiring errors are benign and we can rectify any issues, however we have seen many cases of UH8 units blown to bits due to an engineer shorting out some of the contacts on the board. In this instance, we’ll need to source a new UH8!

rectifying a poorly installed underfloor heating system

3. Incorrectly paired thermostats

We would always prefer to hard-wire underfloor heating controls where possible. However, when underfloor heating control has been retrofitted, Heatmiser offer a battery-powered wall mounted stat. A common issue we find is that the thermostat has been paired with the wrong zone on the UH8. The upshot of this is that the thermostat might be sat in a cold utility room: if it is paired with the zone controlling the lounge, the lounge will always be too warm as the stat will always be calling for heat from the boiler.

We found an incorrectly paired thermostat while rectifying problems with this underfloor heating installation

4. Wireless stats our of range for app-control

Once the stats are paired correctly with the UH8, they communicate via RF: this is a strong signal, and we rarely have issue with this side of things. We can then set about installing a Neohub which allows remote app-based or desktop-based control of your heating. Schedules can be set up remotely, and programming is easier on the app than on the devices directly. However, communication between the hub and the stats is via wi-fi: we often have connection issues in larger houses, and houses with stone walls.

This can be mitigated by installing one or more extender units or Neoplugs which extend both the RF and wi-fi signals. If using Neoplugs, these can be added to the system as app-controllable smart plugs where schedules can be set to automate things like table lamps, fans etc.

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