Heating, hot water and environment — Smart Home Technology Practice

Sample questions

1. 01A smart heating system has a wall unit, a receiver at the wiring centre, a gateway on the router and an app. Which part actually gives the boiler its call for heat?

   • AThe relay inside the receiver unit
   • BThe app on the customer’s mobile phone
   • CThe gateway plugged into the router
   • DThe vendor’s cloud service and account

   Why: The receiver’s relay (or its boiler link) is what switches the boiler; everything above it only tells the relay what to do. The gateway is tempting because it looks like the “brain”, but it only joins the system to the internet for remote access. The app and the cloud are remote features, and the heating should keep working without them.

2. 02On a new build, the kitchen and the utility room next to it share one room thermostat, with no TRVs in either. Building control asks how that meets 5.20. What is the answer?

   • ARooms with tiled floors are exempt from room-by-room control
   • BKitchens have cooking heat gains, so they need no room control
   • CAny two rooms on the same floor may share a single thermostat
   • DAdjacent rooms of similar use and heat need may be one zone

   Why: Paragraph 5.21 allows a zone instead of individual rooms where two adjacent rooms have a similar use and heating need, and a kitchen with its utility room is the usual example. The tempting “any two rooms on the same floor” goes far wider than 5.21 allows. Floor finish and cooking heat gains are not grounds in the guidance.

3. 03On a boiler swap you check the existing TRVs. Most work properly, but one weeps at the valve and one is seized. What does the job need to meet 5.20?

   • ARemove the two faulty heads and leave those radiators uncontrolled
   • BReplace every TRV in the house, as all must be new with the boiler
   • CLeave them all, as existing TRVs are accepted whatever their state
   • DReplace the leaking and seized ones; the working TRVs can stay

   Why: Paragraph 5.20 asks for thermostatic control in each heated room, not new valves. A TRV that does not leak, is not stuck and really changes the radiator output can stay; one that fails those checks needs replacing. Replacing every valve is tempting but is not required, while leaving faulty ones, or taking the heads off, leaves rooms without control.