Roger440 Posted December 15, 2022 Share Posted December 15, 2022 My lovely new UFH is, well, lovely. Except the control is crap. Ther thermostat doesnt switch off or on the pump until its 1.5 degrees past the target temp. Which means a variation of 3 degrees. Its a Hetta HM01PT for what its worth. Which claims a measurement accuracy of 0.1 degrees. The instructions seem to suggest this not adjustable or configurable. Is this normal, or is this just a particuarly crap device? Assuming its dustbin material, whats my best option for something with much tighter control? Link to comment Share on other sites More sharing options...
JohnMo Posted December 15, 2022 Share Posted December 15, 2022 Most thermostats are pretty rubbish. I am using Salus thermostat wg610, I think, that is set at +/-0.25 hysterisis and that is pretty rubbish due to time it takes to move room temp with UFH. I found getting the flow temp right is the most important thing. A couple degrees either way from ideal will cause under or over temp issues. I currently have my thermostats setting moved out the way. And pretty much fined tune the flow temp based on outside temperature. For me 31 to 32 is ok sub zero and 25 to 26 at about 10 degrees work pretty well. These are the best I've seen for hysterisis. Q7RF-Manual-EN.pdf Link to comment Share on other sites More sharing options...
dpmiller Posted December 16, 2022 Share Posted December 16, 2022 Yep Hetta stuff is just branded chinesium with a big premium. I've got their old wireless underfloor system, which is actually still available on Aliexpress as a BEOK. The 'stats are "ok" but it's not really perfect for an ASHP-based system as the boiler cycles-per-hour isn't configurable. Hetta didn't even have the courtesy to reply to a query I had... Link to comment Share on other sites More sharing options...
ProDave Posted December 16, 2022 Share Posted December 16, 2022 So are you actually saying the room temperature on the display can be say 1 degree higher than the set point, and it is still showing the wiggly line "heating" symbol on the thermostat? Link to comment Share on other sites More sharing options...
dpmiller Posted December 16, 2022 Share Posted December 16, 2022 Most of these stats have a configurable hysteresis (on/ off) setting. It could well be set to 2 or 3 degrees from the factory... The manual should give you a menu list for these settings. The unit might be able to *measure* within 0.1c bit it can only display in 0.5c steps. Link to comment Share on other sites More sharing options...
Roger440 Posted December 16, 2022 Author Share Posted December 16, 2022 3 hours ago, ProDave said: So are you actually saying the room temperature on the display can be say 1 degree higher than the set point, and it is still showing the wiggly line "heating" symbol on the thermostat? Yes! Crap isnt it. Link to comment Share on other sites More sharing options...
Roger440 Posted December 16, 2022 Author Share Posted December 16, 2022 1 hour ago, dpmiller said: Most of these stats have a configurable hysteresis (on/ off) setting. It could well be set to 2 or 3 degrees from the factory... The manual should give you a menu list for these settings. The unit might be able to *measure* within 0.1c bit it can only display in 0.5c steps. Well, if it does, it not in any of the instructions. Link to comment Share on other sites More sharing options...
Roger440 Posted December 16, 2022 Author Share Posted December 16, 2022 4 hours ago, dpmiller said: Yep Hetta stuff is just branded chinesium with a big premium. I've got their old wireless underfloor system, which is actually still available on Aliexpress as a BEOK. The 'stats are "ok" but it's not really perfect for an ASHP-based system as the boiler cycles-per-hour isn't configurable. Hetta didn't even have the courtesy to reply to a query I had... No reply to mine either. Link to comment Share on other sites More sharing options...
Roger440 Posted December 16, 2022 Author Share Posted December 16, 2022 12 hours ago, JohnMo said: Most thermostats are pretty rubbish. I am using Salus thermostat wg610, I think, that is set at +/-0.25 hysterisis and that is pretty rubbish due to time it takes to move room temp with UFH. I found getting the flow temp right is the most important thing. A couple degrees either way from ideal will cause under or over temp issues. I currently have my thermostats setting moved out the way. And pretty much fined tune the flow temp based on outside temperature. For me 31 to 32 is ok sub zero and 25 to 26 at about 10 degrees work pretty well. These are the best I've seen for hysterisis. Q7RF-Manual-EN.pdf 1.18 MB · 5 downloads Thanks for the info. I was hoping not to have to mofify my freshly completed wall. Looks like i will be. The Hetta one fits in a single socket back box. Link to comment Share on other sites More sharing options...
JohnMo Posted December 16, 2022 Share Posted December 16, 2022 Salus ones also fit a single wall socket Can be wired or wireless Link to comment Share on other sites More sharing options...
Roger440 Posted December 16, 2022 Author Share Posted December 16, 2022 1 hour ago, JohnMo said: Salus ones also fit a single wall socket Can be wired or wireless Excellent. Your link shows pics of a double size one. Looking like a job for next week Link to comment Share on other sites More sharing options...
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