Conservation of fuel and power: Approved Document L, Volume 1 — Dwellings

O N L I N E V E R S I O N R44, R44ZA, L1(b), L2(b) System specific guidance for commissioning Hot water systems for space and domestic hot water heating 8.8 Before a new heating appliance is installed, all central heating and primary hot water circuits should be thoroughly cleaned and flushed out. A suitable chemical inhibitor should be added to the primary heating circuit to protect against scale and corrosion. In hard water areas, suitable measures should be taken to treat the feed water to water heaters and the hot water circuit of combination boilers to reduce limescale accumulation. Domestic central heating systems should be prepared and commissioned to BS 7593. NOTE: The Benchmark Commissioning Checklist can be used to show that commissioning has been carried out satisfactorily for the heating and hot water system and its heat generation source. Heat pump heating systems 8.9 Heat pumps and any dedicated ancillary products, e.g. integrated hot water cylinders, should be commissioned in accordance with both the manufacturer’s instructions and the appropriate system design parameters. 8.10 If using a ground source heat pump the commissioning procedure for the ground array should be as follows. a. Ground arrays – including header pipes and manifolds – should be flushed as one system to remove all debris and purged to remove all air. Vertical, horizontal and slinky ground arrays in particular should be flushed in both directions. During this process, the heat pump (along with its accompanying pipework) should be isolated from the ground heat exchanger such that damage to the internal heat exchanger inside the heat pump is avoided. b. The heat pump – along with its accompanying pipework – should be flushed and purged as a separate system while isolated from the ground array system. c. Following the complete purging of micro air bubbles, a pressure test (in accordance with BS EN 805, section 11.3.3.4) should be conducted on all closed-loop ground source heat pump installations to prove the integrity of the systems. This test should be conducted on the entire system, which typically comprises the heat pump, header pipes, manifold and all ground arrays. d. Antifreeze and biocide should be added to ground heat exchangers as appropriate, in line with manufacturer’s instructions. 8.11 Commissioning information provided to the dwelling owner should include details of the fluids used and their comissioned concentrations. Community heating systems 8.12 For district heat networks and community heating systems, both of the following should be done. a. Systems should be commissioned to optimise the use of energy for pumping. b. Flow rates in individual heat emitters should be balanced using either of the following. i. Appropriate return temperatures. ii. Calibrated control valves. Underfloor heating 8.13 All installed equipment in underfloor heating systems should be commissioned in accordance with BS EN 1264-4. 56 Approved Document L Volume 1, 2021 edition Building Regulations 2010 O N L I N E V E R S I O N