2 Central heating practice

Pump Operation with TRVs

• A bypass valve allows the pump to operate at a minimum flow rate when thermostatic radiator valves (TRVs) are fitted.

Vent Pipe Height in F&E Cistern

• The vent pipe should rise 450 mm above the water level in a fully pumped F&E (Feed and Expansion) cistern.

Building Regulations for Energy Conservation

• Part L1 of the Building Regulations specifies the requirements for energy conservation in heating systems.

Controlling Gravity Primaries in a Pumped System

• A motorized valve controls the operation of gravity primaries in a properly controlled system with pumped heating and gravity hot-water primaries.

Water Expansion in Central Heating Systems

• Water in a central-heating system expands by approximately 4% when heated.

Panel Radiator Function

• A panel radiator works mostly by convection.

Independent Control of Heating and Hot Water

• A diverter valve permits the independent control of heating and hot water.

Replacement Pump Too Short

• Obtaining pump extensions is the appropriate solution if a replacement pump is too short for the gap it needs to fit into.

TRV Valve Body Operation

• Gas-filled bellows can be used in a Thermostatic Radiator Valve (TRV) to operate the valve body.

Quickest Room Heating

• A fan-assisted convector is the heat emitter that will heat a room the most quickly.

Boiler Drainpipe Requirement

• A condensing boiler requires a drainpipe.

Boiler Efficiency Rating

• SEDBUK is the rating against which the seasonal efficiency of a boiler is measured.

Replacing a Pump: First Action

• Isolating the electricity supply should be the first action when replacing a pump.

Central Heating System Pressure Test Duration

• The duration of a pressure test for a central-heating system is 30 minutes.

Heating System Pipe Configuration

• A one-pipe circuit defines a heating system circulating a pipe around the house from the boiler flow back to the return.

Central Heating System Test Pressure

• Two times the working pressure is the test pressure for a central-heating system.

Mid-Position Valve Common Port Marking

• AB marks the common pipework connection port on a mid-position valve.

Best Position for Pump on Heating Circuit

• The return pipe is the best position for a pump on a heating circuit

Valve with Tamperproof Cap

• A valve with a tamperproof cap as a cover is called a lockshield valve.

Open Vent Size for Heating System

• 15 mm is the minimum size for the open vent to a heating system.

Two-Pipe System Characteristic

• Flow and return pipework are separated in a two pipe system.

Minimum Pipe Size for Solid Fuel Boiler

• 28mm is the minimum pipe size for primary flow and return pipework from an independent solid fuel boiler to a hot water storage cylinder.

Temperature in a One-Pipe System

• The temperature of the last radiator on the circuit will be cooler than the first in a one pipe system

Open Vent Size for Fully Pumped System

• 28mm is the normal size of the open vent to a fully pumped heating system in a domestic property.

Connecting Open Vent and Cold Feed

• An Injector tee facilitates the connection of an open vent pipe and a cold feed pipe in a fully pumped system.

Zone Valve Function

• A zone valve in a pumped heating circuit is designed to isolate the circuit when the desired temperature is reached.

Combined System F&E Cistern

• Water level in the F&E cistern should be set to allow for thermal expansion in a combined hot water and central heating system, including an F&E cistern with gravity primaries and pumped heating circuits.

Minimum Size for Primary Cold Feed

• 22mm is the minimum size for a primary cold feed for a hot water heating system.

Filling a Central Heating System

• Remove the pump (accelerator) and replace it with a piece of temporary piping before filling a central heating system for the first time.

Flux Removal

• Hot flushing a system as part of the commissioning process assists in the removal of flux from heating systems pipework.