Horne 15 & 20 Brochure (2MB, pdf) Horne 15 (Type H1503) & Horne 20 (Type H2003) Technical brochure. A UK Water Reg 4 and Type 3 Approved Thermostatic Mixing Valve compliant to Model Engineering Specification D08 / D 08 Thermostatic Mixing Valves (Healthcare Premises). Issue 8, September 2023. More