Browse categories of Biomass ThermoBloc™ (recirc and distribution units) ThermoProtec™ (mixing valves) Accessories Condensing boiler protection valves. ThermoBloc™ (recirc and distribution units) ThermoBloc™, Recirculation and distribution unit ThermoProtec™ (mixing valves) ThermoProtec™, Thermostatic mixing valve (high-flow) Accessories Spare thermostats (for anti-condensation valve) Dual scale temperature gauge