apostolakisl Posted June 4, 2014 Posted June 4, 2014 Stepping back and thinking about the whole logic... Why consider the armed away status at all? Are we afraid we will prewarm hot water taps for burglars? Simplify by triggering the pump from by occupancy detectors already in place. Turn off in 2-5 minutes. If the pump timers get retriggered repeatedly...so what? As long as we are in the bathroom we want the water hot and ready anyway. It still will a lot cheaper than running 6 am - 10 pm and will trigger in the middle of the night if visiting the bathroom for a hand wash. If status bath is on or status kitchen is on or status motion sensor is on then turn pump on wait 3 minutes turn pump off else - I think the deal was that he wanted the water to stay warm while the room was in use, even if the water wasn't in use. This would only heat it initially. But for the most part, I would think that in a bathroom, you would actually only need it heated initially and then once you got in there you would actually be using the water which would keep it hot. The kitchen could be different. I don't disagree with the logic of the alarm, except ISY gets the status wrong on devices sometimes (comm issues), so I don't think it is a bad way to override an incorrect Insteon status. I have never had ISY get the alarm system status wrong (mostly since it is not an Insteon comm).
larryllix Posted June 4, 2014 Posted June 4, 2014 I think the deal was that he wanted the water to stay warm while the room was in use, even if the water wasn't in use. This would only heat it initially. But for the most part, I would think that in a bathroom, you would actually only need it heated initially and then once you got in there you would actually be using the water which would keep it hot. The kitchen could be different. I don't disagree with the logic of the alarm, except ISY gets the status wrong on devices sometimes (comm issues), so I don't think it is a bad way to override an incorrect Insteon status. I have never had ISY get the alarm system status wrong (mostly since it is not an Insteon comm). If we knew what these sensing devices throw out once habitation of those areas has ceased we could design a stop programme to arrest a cyclic pump pipe heating loop. I think I like your 2 program idea but prefer it using a variable to state "I am already in a cycle". The small recirculating Grundfos pump comes with programmable timer to eliminate wasted heat in off times but it has no smarts for Not_home or I'm_up_in_the_middle_of_the_night etc... It's starting to look like a holding tank so we don't wear out the switching on the tankless. Unfortunately, this thread has got me enthused to do this in my own home. I thought I was smart and installed manifolds on both cold and hot but the hot one was a mistake. My kitchen is the farthest away and with the stupid water saver taps we have been known to wait... sometimes we think the water heater has failed. Seems about 60-90 seconds. The dishwasher seems to pull up the hot water very quickly so we know it's the water saver faucets. My idea (when I get time) is to put my air handler loop at the end of the long run to the kitchen so in the winter the hot, or some level of warm, water should be there immediately. Volumes and pressure drop will be learned by trial and error. recovery will be a small PEX crimp back the way it was. The recirc pump gives me more ideas! Love PEX! - The cliplead of plumbing!
jmed999 Posted June 5, 2014 Author Posted June 5, 2014 Stepping back and thinking about the whole logic... Why consider the armed away status at all? Are we afraid we will prewarm hot water taps for burglars? Simplify by triggering the pump from by occupancy detectors already in place. Turn off in 2-5 minutes. If the pump timers get retriggered repeatedly...so what? As long as we are in the bathroom we want the water hot and ready anyway. It still will a lot cheaper than running 6 am - 10 pm and will trigger in the middle of the night if visiting the bathroom for a hand wash. If status bath is on or status kitchen is on or status motion sensor is on then turn pump on wait 3 minutes turn pump off else - A couple of things... -I have now incorporated from 5AM to 6AM into the programs. If I go on vacation it will continue to run during that time but not if the alarm is armed. -I have a pretty sophisticated Grundfos Alpha pump and I'd rather not turn it off and on every two minutes. Also, keep in mind, if the pump runs 2 minutes the electric heater is flushed with cooler water and will run for 20 min since it has a 20 min reheat time. The pump is 16 watts and the electric tank is ~1400 watts so the electric heater is my main concern money wise.
apostolakisl Posted June 6, 2014 Posted June 6, 2014 Stepping back and thinking about the whole logic... Why consider the armed away status at all? Are we afraid we will prewarm hot water taps for burglars? Simplify by triggering the pump from by occupancy detectors already in place. Turn off in 2-5 minutes. If the pump timers get retriggered repeatedly...so what? As long as we are in the bathroom we want the water hot and ready anyway. It still will a lot cheaper than running 6 am - 10 pm and will trigger in the middle of the night if visiting the bathroom for a hand wash. If status bath is on or status kitchen is on or status motion sensor is on then turn pump on wait 3 minutes turn pump off else - A couple of things... -I have now incorporated from 5AM to 6AM into the programs. If I go on vacation it will continue to run during that time but not if the alarm is armed. -I have a pretty sophisticated Grundfos Alpha pump and I'd rather not turn it off and on every two minutes. Also, keep in mind, if the pump runs 2 minutes the electric heater is flushed with cooler water and will run for 20 min since it has a 20 min reheat time. The pump is 16 watts and the electric tank is ~1400 watts so the electric heater is my main concern money wise. Why are you using the electric heater? If you are going to shut down the recirc pump for 20 minutes at a time, you can just circulate through the on demand tank. Probably at most you might see a half dozen extra cycles on your on-demand tank per day based on a wait time of 20 minutes and only triggering on those lights being on. Also, the 20 minute off time should give plenty of time for the water to cool sufficiently for it to kick on the on demand heater. If you set your on-demand at around 130, then after 20 minutes of sitting in the lines, I would think the water would drop to around 100 or so. Really the only piece of the puzzle missing is that you could put a temp probe on the water line and only let the program run if the temp is lower than 105 or so. A webcontrol board plus a one-wire temp probe would easily do that for about $40.
jmed999 Posted June 6, 2014 Author Posted June 6, 2014 This is the programs I ended up with... Pump 1 If ( Status 'Guest Bath Light' is On Or Status 'Upstairs Bathroom Light' is On Or Status 'Kitchen Lights' is not Off Or Status 'Bathroom Pump Motion-Sensor' is On Or On Mon, Tue, Wed, Thu, Fri From 5:15:00AM For 2 minutes ) And Elk Area 'The Home' 'Armed State' is not Armed Away Then Run Program 'Pump2' (If) Else Stop program 'Pump2' Set 'Pump Power' Off Pump 2 If Status 'Guest Bath Light' is On Or Status 'Bathroom Pump Motion-Sensor' is On Or Status 'Upstairs Bathroom Light' is On Then Repeat 100 times Set 'Pump Power' On Wait 2 minutes Set 'Pump Power' Off Wait 10 minutes Else Set 'Pump Power' On Wait 2 minutes Set 'Pump Power' Off Wait 10 minutes Repeat 100 times Set 'Pump Power' On Wait 10 minutes Set 'Pump Power' Off Wait 20 minutes I still think there is some fine tuning that can be done here but this is what I have for now.
jmed999 Posted June 6, 2014 Author Posted June 6, 2014 Stepping back and thinking about the whole logic... Why consider the armed away status at all? Are we afraid we will prewarm hot water taps for burglars? Simplify by triggering the pump from by occupancy detectors already in place. Turn off in 2-5 minutes. If the pump timers get retriggered repeatedly...so what? As long as we are in the bathroom we want the water hot and ready anyway. It still will a lot cheaper than running 6 am - 10 pm and will trigger in the middle of the night if visiting the bathroom for a hand wash. If status bath is on or status kitchen is on or status motion sensor is on then turn pump on wait 3 minutes turn pump off else - A couple of things... -I have now incorporated from 5AM to 6AM into the programs. If I go on vacation it will continue to run during that time but not if the alarm is armed. -I have a pretty sophisticated Grundfos Alpha pump and I'd rather not turn it off and on every two minutes. Also, keep in mind, if the pump runs 2 minutes the electric heater is flushed with cooler water and will run for 20 min since it has a 20 min reheat time. The pump is 16 watts and the electric tank is ~1400 watts so the electric heater is my main concern money wise. Why are you using the electric heater? If you are going to shut down the recirc pump for 20 minutes at a time, you can just circulate through the on demand tank. Probably at most you might see a half dozen extra cycles on your on-demand tank per day based on a wait time of 20 minutes and only triggering on those lights being on. Also, the 20 minute off time should give plenty of time for the water to cool sufficiently for it to kick on the on demand heater. If you set your on-demand at around 130, then after 20 minutes of sitting in the lines, I would think the water would drop to around 100 or so. Really the only piece of the puzzle missing is that you could put a temp probe on the water line and only let the program run if the temp is lower than 105 or so. A webcontrol board plus a one-wire temp probe would easily do that for about $40. I'm using the electric heater for several reasons. It keeps the recirc line warm at all times while the pump is running without taxing the tankless water heater. This method also produces no cold water sandwich. Also, it keeps the water temp very steady, ie. when in the shower I get the 1st 4 gallons at about 115F then when the hot water from the tankless reaches the shower head (after about 2 minutes of showering) it's also at about 115F so no varying temp which means no hot water surprises for my wife and baby. I will be adding more to/from time to the program in a couple weeks when my family's schedule gets into more of a routine (when my wife goes back to work from having the baby). The water heater has a clear advantage when scheduled times are implemented. With the programs, I have instant (within 5 seconds) hot water when needed at all sinks, showers, etc. and I have the electric cost down to about $10-$15 per month. It used to take about 90 seconds to get hot water. Keep in mind, the water temp from the tankless heater is just slightly higher than the electric tank so once hot water is turned on, the water from the tankless enters the electric heater turning the heating elements on the electric heater off. I love this setup. How do you know how long it takes my recirc line to cool without knowing where I live, the line material, the insulation type, length, etc.? As I've said, I have an auqastat that I could put in. Therefore, I have no need for the webcontrol. The auquastat would turn the pump on at 105F but I don't think it would help. If you knew my setup I think you would agree. The issue with turning the pump off at a temp is varying water temp/hot water surprises and the electric heater would continue to run even if the stat turns the pump off. The water heater turns on and off at it's own setpoints, no need to add additional pump setpoints when the pump is only 16 watts. The auqastat would only complicate the system making tweaks to the program based on experience more difficult. I know my system very well and at this point I'm happy with my programming thanks to the help from you guys. I'm sure it could be tweaked but that will come with experience.
apostolakisl Posted June 6, 2014 Posted June 6, 2014 How do you know how long it takes my recirc line to cool without knowing where I live, the line material, the insulation type, length, etc.? Your pipes are running in your crawl space, which is probably reasonably close to house temp. The length of line is irrelevant. Hot water pipe insulation is pretty much a standard. And that is about how long it takes my pipes to cool which are running at house temp with standard hot water pipe insulation.
larryllix Posted June 7, 2014 Posted June 7, 2014 Another interesting factor, just to complicate things, is that most of those Grundfos pumps can be dimmed down and reduce speeds of the impellers. I was told by a few that the frequency was varied from the controllers but my fancy (read expensive) Tekmar pump controller just reduces the voltage to the pump via a triac circuit. The pumps do not have a big range before it may just stall. My pumps are three speed units using internal series capacitors to drop voltage and consequently speed plus the Tekmar outdoor reset control panel triac circuit to vary the injection pump voltage. A slow speed recirc may be a fun factor in your design using a LampLinc module instead of turning the pump on and off. If this pump is the same design as my hydronic heat circulating pumps there isn't much you can do to hurt those things. There is no starting circuit or switches and they can run stalled without any damage (although they do get fairly hot without circulating coolant) , being water lubricated and cooled. Those tiny recirc pumps could be a slightly different design. The only algorithm I could think of at this time would be - on detecting life in a room, give the pump a 100% shot for 2-3 minutes. After that drop pump speed to minimal speed. Shut off with no life, away mode on, etc.. The hot water tank could be turned off on extended away times, but unless you installed another recirc pump feeding back before the tankless, you would pay the whole electric bill to reheat the water each time, and that may take awhile depending on how large and the power rating of recirc heater tank. Ok... gallonage and wattage. Then the Legionella bacteria problem can come into play under lukewarm water conditions in electric DHW tanks, depending on construction and water source.
apostolakisl Posted June 7, 2014 Posted June 7, 2014 Another interesting factor, just to complicate things, is that most of those Grundfos pumps can be dimmed down and reduce speeds of the impellers. I was told by a few that the frequency was varied from the controllers but my fancy (read expensive) Tekmar pump controller just reduces the voltage to the pump via a triac circuit. The pumps do not have a big range before it may just stall. My pumps are three speed units using internal series capacitors to drop voltage and consequently speed plus the Tekmar outdoor reset control panel triac circuit to vary the injection pump voltage. A slow speed recirc may be a fun factor in your design using a LampLinc module instead of turning the pump on and off. If this pump is the same design as my hydronic heat circulating pumps there isn't much you can do to hurt those things. There is no starting circuit or switches and they can run stalled without any damage (although they do get fairly hot without circulating coolant) , being water lubricated and cooled. Those tiny recirc pumps could be a slightly different design. The only algorithm I could think of at this time would be - on detecting life in a room, give the pump a 100% shot for 2-3 minutes. After that drop pump speed to minimal speed. Shut off with no life, away mode on, etc.. The hot water tank could be turned off on extended away times, but unless you installed another recirc pump feeding back before the tankless, you would pay the whole electric bill to reheat the water each time, and that may take awhile depending on how large and the power rating of recirc heater tank. Ok... gallonage and wattage. Then the Legionella bacteria problem can come into play under lukewarm water conditions in electric DHW tanks, depending on construction and water source. The thing is this wouldn't save much. Heat loss is all about the temp delta from inside the insulated pipe to outside the pipe. As you slow the pump down, the end of the line will end up being cooler, but if it is much cooler, then you defeated the whole purpose of this thing. So, in short you are going to run it fast enough to keep the water at the end of the line hot, and thus the delta will still be there and heat loss will still be there. Presumably the pump would use fewer watts at a lower speed and that would be the bulk of your savings. I doubt that the wattage difference would be much, however. Perhaps the pump life would be extended? Or if the pump wasn't intended to run at slower speeds at might be shortened. You would need to know the details on your pump.
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