<p dir="ltr">Cycles per hour is a hangover from the steam boiler and non condensing/modulating water boiler era. Modulating boilers to limit heat input rate and flow temp comp to limit heat output rate is more current practice. </p>
<p dir="ltr">The smaller boilers are more sensitive to mean water temp for condensing purposes than return water temp too: less opportunity to build temperature gradient on the HX compared with commercial scale stuff. Hence weather comp useful. </p>
<p dir="ltr">I understand that the anti-cycling controls in modern boilers, particularly some continental ones, do a decent job of cycling control on their own: you set a constant call for heat and the boiler first gives the (electronic, with feedback provided on actual flow rate achieved) pump a kick to check for flow (open TRVs) in the heating circuit; decides no flow = no actual call for heat and don't bother firing; waits a while depending on (a) length of previous burn and (b) time since you last checked and/or (c) flow temperature then tries again.</p>
<p dir="ltr">Better here than with the TRVs as Damon says imo - leave the weather comp to 'building level' rather than room level.</p>
<p dir="ltr">We have a 7 zone Evohome setup on eBay at the moment by the way - 99p no reserve - as we finished testing with it and nobody in the company would have it in their own home: buggy radio, buggy gateway code, and poorly thought through control logic being the main gripes.</p>
<div class="gmail_quote">On 13 Jul 2016 19:13, "Chris Skerry" <<a href="mailto:chris_skerry@icloud.com">chris_skerry@icloud.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div>Hi,</div><div><br></div><div>My Evohome system takes account of outside temperature and requested time for requested temperature and starts heating early to achieve it.</div><div><br></div><div>It also has a facility to set the number of boiler cycles per hour, if I remember correctly it goes from about 3 to 9.  This is to prevent excessive on/off cycles.  Under certain conditions when all TRVs have have closed the controller is still calling for heat.  So the boiler has to have a bypass.</div><div><br></div><div>The communications system is supposed to allow the 2 x AA batteries in each TRV to last two years  —  I shall see.  </div><div><br></div><div>How will the DH-D system cover these matters?</div><div><br></div><div>Regards,……….Chris.</div><div>.</div><div><div><blockquote type="cite"><div>On 13 Jul 2016, at 16:27, Damon Hart-Davis <<a href="mailto:dhd@exnet.com" target="_blank">dhd@exnet.com</a>> wrote:</div><br><div><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">Hi,</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><blockquote type="cite" style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">On 13 Jul 2016, at 15:10, Simon Hobson <<a href="mailto:linux@thehobsons.co.uk" target="_blank">linux@thehobsons.co.uk</a>> wrote:<br><br>Damon Hart-Davis <<a href="mailto:dhd@exnet.com" target="_blank">dhd@exnet.com</a>> wrote:<br><br><blockquote type="cite"><blockquote type="cite">Just a thought, for those of us where it isn't too much of a problem, is a hardwired connection feasible ?<br></blockquote></blockquote><br><blockquote type="cite">Yes, depending on details of our connector and plastics design.<br><br>But I think that that is a tiny fraction of the people that we want to reach on this round.  We may be able to accommodate such use cases out-of-band, especially if the radio certfication gets too eye-watering.<br></blockquote><br>I was assuming that such cases would be more in the "hack it yourself but here's some ideas" kind of territory. I doubt it would make commercial sense as the proportion of users going that route will be a) very small and b) mostly techies.<br></blockquote><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">1) We want to actively support the geek faction in all we do where possible, even if TRV2.0 is not primarily aimed at it.</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">2) We will at least try not to make it unnecessarily difficult to “hack it yourself”.</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><blockquote type="cite" style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><blockquote type="cite">1) At the moment the radio is one-way.<br></blockquote><br>I didn't realise/had forgotten that<br></blockquote><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">Well, it’s on my list of things to fix but is distinctly non-trivial with our current ISM radios.  It maybe easier with other radios, for example, LoRa has a listen-after-TX mode as standard.  I’ll get Deniz to think about that one too, on his current researches!</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><blockquote type="cite" style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><blockquote type="cite">We have yet to decide what to include in this offering!<br></blockquote><br>I would suggest a "basic working system". I think we can all think of projects that floundered on the rocks of "took too long and tried to add too many bells and whistles". Pack of heads plus a relay unit, pre-paired (optional while you're selling to techies, essential after that), and software with the features you've described.<br>Being able to read the data from the system out-of-the-box would be nice - that way us techies who are likely to he the majority of early adopters can start making pretty graphs that our other halves can go "yes dear, very nice" to in that special "I really don't care" tone of voice they have !<br></blockquote><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">You are absolutely preaching to the converted.  MVP, avoiding feature-itis, etc, is the ONLY way we’re going to get this done at all!</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">Rgds</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">Damon</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">_______________________________________________</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><span style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">OpenTRV-interest mailing list</span><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><a href="mailto:OpenTRV-interest@lists.opentrv.org.uk" style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" target="_blank">OpenTRV-interest@lists.opentrv.org.uk</a><br style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><a href="http://lists.opentrv.org.uk/listinfo/opentrv-interest" style="font-family:GillSans;font-size:18px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px" target="_blank">http://lists.opentrv.org.uk/listinfo/opentrv-interest</a></div></blockquote></div><br></div></div><br>_______________________________________________<br>
OpenTRV-interest mailing list<br>
<a href="mailto:OpenTRV-interest@lists.opentrv.org.uk">OpenTRV-interest@lists.opentrv.org.uk</a><br>
<a href="http://lists.opentrv.org.uk/listinfo/opentrv-interest" rel="noreferrer" target="_blank">http://lists.opentrv.org.uk/listinfo/opentrv-interest</a><br>
<br></blockquote></div>