Technical specification sheet for Oventrop differential pressure relief valves, models PN 10, max. temperature 120 °C, with nominal value adjustable between 50 and 500 mbar. Covers two variants: standard and with preset indicator. Lists item numbers for DN 20, DN 25, and DN 32 sizes. Includes function description, application examples for central heating systems, and installation guidance.…
This document is a technical specification sheet for Oventrop differential pressure relief valves, model PN 10, with a maximum temperature of 120 °C and nominal value infinitely adjustable between 50 and 500 mbar. It is intended for engineers, installers, and system designers working with central heating systems and gas fired continuous-flow water heaters.
The sheet covers two valve variants: the standard differential pressure relief valve (item numbers 1085006, 1085008, 1085010) and the version with a preset indicator (item numbers 1085206, 1085208, 1085210). Both are available in DN 20, DN 25, and DN 32 sizes. The body is made of bronze or brass, with EPDM gaskets and a stainless steel spring.
The function section explains that the valve prevents disturbing flow noises during part load conditions and maintains minimum water circulation when regulating valves are closed. It is installed in a bypass pipe between supply and return. The control range is 50 to 500 mbar, preset at works to 200 mbar.
Dimensions are provided in a table showing thread sizes (Rp 3/4, Rp 1, Rp 1 1/4) and lengths L, L1, L2, and height H for each DN size and item number. Flow charts for DN 32 show characteristic lines for both valve types, with opening pressure determined by handwheel turns or preset indicator value.
A selection guide recommends valve size based on maximum excess flow: DN 20 for up to 0.55 l/s, DN 25 for up to 0.85 l/s, DN 32 for exceeding 0.85 l/s. An example application demonstrates how to determine valve size and setting for a heating system with thermostatic valves at a design flow of 0.28 l/s and 25 kPa pressure loss.
Setting instructions are given for both variants. For the preset indicator model, set the required opening pressure by turning the handwheel. For the standard model, turn the handwheel to the minus stop, then turn plus according to the number of turns from the chart. Settings can be locked by tightening the handwheel screw.