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- 27 Jan 2008
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- Llanfair Caereinion, Nr Welshpool
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Red ovals are the radiators, orange square is the thermostat, kitchen has a eQ-3 programmable TRV head, toilet shower is a old wax type and the rest are MiHome Energenie heads, the thermostat is a Nest 3rd generation.
Can't move thermostat boiler in floor below and have to use existing wiring. But by time the wall thermostat has warmed up, there is a lot of heat around and it over shoots, there is a huge difference depending on if doors left open or closed, and my idea of linking the TRV heads to the wall thermostat has failed.
So I think if I set the TRV heads right it will slow heating as it approaches target and reduce the hysteresis, all but one TRV head is programmable, so with careful setting of times or/and adjusting lock shield valves I should be able to reduce the hysteresis.
But can't get my head around what to adjust first, it seems the boiler is too big, it will run for around half and hour before it starts to cycle, 18 kW three floors, the granny flat I can forget hardly used and has its own pump, zone valve and wall thermostat so that is in real terms independent.
What I want is for the wall thermostat to switch off/on with no more than an hour between each run, this will mean up stairs room TRV heads will have some hot water to work with, but at moment it is switching with around 3 to 4 hours between each run, as it over shoots so much.
Been use to gas before this house with a modulating boiler, now using oil simple off/on boiler, and just can't get head around what I need to do.