From d481d379d4db0690ef1e49ac063290afaa8890e5 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Thu, 9 May 2024 08:31:13 +0100 Subject: [PATCH] Adjust delta for new input sensor --- pool.yaml | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/pool.yaml b/pool.yaml index badd278..b43b229 100644 --- a/pool.yaml +++ b/pool.yaml @@ -74,23 +74,27 @@ script: // We consumed this reading pair. //id(solar_out_fails) = id(solar_in_fails) = 1; - // We believe the output sensor is reading slightly lower than the - // input sensor. We see a fair amount of hysteresis, and the bypass - // kicks in before the output reports lower than the input... but - // the roof temperature continues to rise. When it gets high enough, - // the bypass turns off again and the warm water is pumped out. But - // then the reported output temperature is lower than the input again - // and it switches off again. Repeatedly, each 5 minutes over the - // course of an hour or so. + // The sensors are not perfectly calibrated. We believed the original + // input sensor was reading slightly higher than the output sensor, + // and we saw a fair amount of hysteresis. The bypass opened when the + // output *reported* lower than the input... but the temperature in + // the roof continued to rise. When it got high enough, the bypass + // closed again and the warm water was pumped out. But then the + // reported output temperature was lower than the input again and it + // switched off again. Repeatedly, each 5 minutes over the course of + // an hour or so. // - // By adjusting the output sensor up by about 0.1°C we attempt to - // reduce this hysteresis. Overcorrection would mean that we keep - // pumping heat into the sky for longer than we should, which is - // much worse than a little bit of hysteresis when the heat *is* - // actually accumulating in the water on the roof even while we - // vacillate. + // By adjusting the input sensor down by about 0.1°C we attempted to + // reduce this hysteresis. Overcorrection would mean that we we keep + // pumping heat into the sky for longer than we should, which is much + // worse than a little bit of hysteresis when the heat *is* actually + // accumulating in the water on the roof even while we vacillate. // - outtemp += 0.2; + // Having replaced the valve assembly in 2024, the new input sensor + // seems to be reading *lower* than the output by about 0.2°C, so we + // end up pumping heat into the sky, especially in the evenings. So + // we now make the correction in the opposite direction. + intemp += 0.2; if (outtemp == intemp) return; -- 2.50.1