Plug In-Style Thermostat
As stainless-steel unvented cylinders are becoming more commonplace, the factory fitted immersions can vary, most of them will use a rod style thermostat with a different colour head, and there are some subtle differences between them:
RTS 3 – Brown Cap
Dual function rod / stem thermostat, with an adjustable trip and safety cut-out. Both functional and safety cut-out are bi-polar with bimetallic disc.
Unival - Blue Cap
Unipolar stemmed type thermostat, for single fuse voltage bipolar bimetallic safety device with manual reset.
TSR - White Cap
Direct plug-in thermostat with 1-pole temperature regulation and 2-pole safety limiter.
TSE – Green Cap
Direct plug-in rod combination thermostat with 1-pole temperature regulation and 2-pole safety limiter.
All of these thermostats are designed to work with unvented cylinders, but the TSR versions are better suited to cylinders with a built-in air gap, as they are less prone to being influenced by any ambient heat build-up and also the temperature is read in the stem triggering a reaction in the head making them more accurate when used with this type of cylinder.