Cheesed off with the cycling a TPI-only wireless roomstat induces (at least once per hour, and most TPI-based roomstats can only offer a minimum of 2 cycles per hour), and on the strength of @Old_Scientist’s favourable comments (e.g. the ability to select hysteresis-based control instead of TPI) I ordered an EPH CP4v2 to replace my ageing Honeywell T3R (which has a minimum cycle rate of 1 per hour).
The CP4v2 arrived this morning, and I installed it a few hours ago. Early observations say it’s doing just what it says on the tin (switches on and off when the displayed room temperature matches the hysteresis settings I’ve programmed in), so (at least today) inducing cycling every 2 hours or so - rather better than the hourly cycles I was getting with the T3R, albeit with a slightly noticeable room temperature swing.
But here’s the funny thing. As I loosened the cover screw on the T3R’s receiver, the heat pump tripped again (ref. Samsung 8kW HTQ Repeated Trips - any suggestions?). I’m now wondering whether a fault had developed in the T3R receiver - after all, it ought to be just conveying “demand” or “no demand” signals (not an obvious source of a trip). Wouldn’t it be nice if @Old_Scientist’s observations had solved two problems for me - over-frequent cycling and unexplained trips? We’ll see over the next few days…