Electric Radiant Floor Heating Thermostat

[deirwin]

I am having a hard time figuring how to tie-in my electric radiant floor heating into my automation system.  I have ISY 994 w/Z-Wave and an ELK M1 Gold system.  Has anyone had any luck with this?  It seems these systems are cutting edge and would then naturally have z-wave or internet or HA thermostats.  Would appreciate any suggestions.  Thanks!

[Teken]

I would think it comes down to what kind of interface is available from the existing TSTAT. Knowing this will allow you and others to provide some feedback.

 

If you could provide a link to the product in place this would be a good start for others review and consume.

 

 

Ideals are peaceful - History is violent

[stusviews]

There are internet, Insteon and Z-Wave solutions. An internet solution is self-contained, only the thermostat is needed. But, it you want control via the ISY then you'll need an Insteon or Z-Wave thermostat and an Aube 840T to interface between the thermostat and your heating system.

[deirwin]

Thanks Teken.  I haven't yet bought thermostats.  I hope this helps.  I have 120v Schluter Ditra Heat System.  It has an in-floor sensor.  The thermostat they sell for this system:

Technical Specifications

Supply voltage:

120/208/240 VAC, 50/60 Hz

Maximum electrical current with a resistive load:

16 A
3840 W @ 240 VAC 3330 W @ 208 VAC 1920 W @ 120 VAC

Temperature Display Range:

0 °C to 35 °C (32 °F to 95 °F)

Temperature display resolution:

1 °C (1 °F)

Range of the temperature set points:

3 °C to 35 °C (37 °F to 95 °F)

Temperature set point increments:

1 °C (1 °F)

Storage:

-30 °C to 50 °C (-22 °F to 122 °F)

[stusviews]

The relay I linked to is for 240VAC. Here's a 120VAC relay: http://www.supplyhouse.com/Honeywell-Aube-RC840T-120-120v-Relay-w-Built-In-24V-Transformer

[deirwin]

Thanks Stu, so I just hook this up with whichever smart thermostat I want and I'll be good?

[stusviews]

Yes. The relay allows you to connect any smart or dumb thermostat that works with any standard HVAC system. The relay requires line, neutral and load wires.

[deirwin]

If we want z-wave or Insteon, I guess we then ignore the in-floor sensor?  So, it will just turn on and stay on until room gets to a certain temp?  Or i program to stay on for a certain amount of time?  Doesn't seem logical for radiant heat.  Have you had luck with this?  Any wisdom is welcome.

[Teken]

If we want z-wave or Insteon, I guess we then ignore the in-floor sensor?  So, it will just turn on and stay on until room gets to a certain temp?  Or i program to stay on for a certain amount of time?  Doesn't seem logical for radiant heat.  Have you had luck with this?  Any wisdom is welcome.

 

I am hesitant to think using a TSTAT in place of the in floor sensor would provide the correct temperature reading. The in floor heating would have to get fairly hot before it made an appreciable change in temp.

 

Please correct me if I am wrong your goal is to two fold. One being able to control the in floor heating device the other is monitoring the in floor temperature, correct?

 

I am unsure what sort of access and work you're willing to undertake to accomplish this task. But, using any flavor of 1-wire sensor network will address the temperature monitoring aspect and allow you to send the temperature via *State Variables* to the ISY Series Controller.

 

To control the power of the in floor heating I would gather simply using a Micro Relay would facilitate in turning the device on/off. I also assume the device has some type of memory which can be recalled upon power up?

 

If not, then intercepting power and interrupting it is not the correct method because the unit would lose its programming. 

[deirwin]

Thanks Teken.  My goal is simply to access with HI system (Elk/ISY), like all of the other thermostats in the house, and to warm up the floor  & shower in advance of going into those rooms.  And ability to program with iPad or computer.  We would have gone to greater lengths a few weeks ago (and thought we did everything we needed unfortunately), but now the floors are finished.  In the floors, we installed the sensors that came with the systems.  We ran those wires to the location of the thermostats will be.  Now when hoping up, we realize, we don't have a place to tie-in up the sensor.  Also, not sure if this helps in this situation, but each room still has telephone lines in the walls in case we ever want/need them (bathrooms used to have telephones in them .

 

It is odd to me that these systems don't offer home automation conveniences, when it feels like they would justify it more than most thermostats, especially since it takes longer to reach temp goals and they are expensive luxury-type systems right now.

[Teken]

Thanks Teken.  My goal is simply to access with HI system (Elk/ISY), like all of the other thermostats in the house, and to warm up the floor  & shower in advance of going into those rooms.  And ability to program with iPad or computer.  We would have gone to greater lengths a few weeks ago (and thought we did everything we needed unfortunately), but now the floors are finished.  In the floors, we installed the sensors that came with the systems.  We ran those wires to the location of the thermostats will be.  Now when hoping up, we realize, we don't have a place to tie-in up the sensor.  Also, not sure if this helps in this situation, but each room still has telephone lines in the walls in case we ever want/need them (bathrooms used to have telephones in them .

 

It is odd to me that these systems don't offer home automation conveniences, when it feels like they would justify it more than most thermostats, especially since it takes longer to reach temp goals and they are expensive luxury-type systems right now.

 

1. If you remove power from in floor heating control box does it recall the pre-set temp upon boot up?

 

2. Are you aware of what sort of sensors are being used for this in floor heater? Is it a simple thermistor or Dallas 1-Wire?

 

3. Having those telephone wires in each room will prove most excellent if you decide to pursue a 1-Wire system. You could simply install cheap 1-wire sensors into the cover plate like this:

 

 

 

[deirwin]

1. If you remove power from in floor heating control box does it recall the pre-set temp upon boot up?

 

2. Are you aware of what sort of sensors are being used for this in floor heater? Is it a simple thermistor or Dallas 1-Wire?

 

3. Having those telephone wires in each room will prove most excellent if you decide to pursue a 1-Wire system. You could simply install cheap 1-wire sensors into the cover plate like this:

 

 

1. I'm not sure, the power is off because thermostats have not been installed. I believe previously with original thermostat, that it remembered presets.  I'm not even sure what would happen now if we used a regular thermostat without the in-floor sensor.  Would it turn on forever?  Do you know if it simply on/off, or do they have on levels?

 

2. It has 2 wires.  Schluter does not seem to give info on their sensors, but apparently compatible with most, if not all, radiant heating thermostats.

 

3. Would this be a benefit in this application?  Install a sensor (and other necessary hardware), then program the system for thermostat on/off?

 

Thanks again!

[Teken]

2. If it only has two wires its not based on the Dallas 1-Wire sensor protocol. As it requires three wires positive, negative, data.

 

3. I was speaking more from a point of temperature monitoring through out the house. As I have done in mine, where having a large sensor grid allows me to manage and activate various Insteon enabled devices such as fans, vents, exhaust, and HVAC.

 

You could definitely use any of the 1-Wire hardware devices to help aid you in this aspect. My only reservation is mounting point(s) and aesthetics.

 

You and I both know as much as we like to tinker it comes down to (WAF) Wife Acceptance Factor) and insuring the home looks nice.

 

I have seen too many (College Dorm) looking half assed installs in my time. The decor must be able to stand up to the general populace and not be distracting or take away from the homes appearance. 

 

If you're more curious about what I have used you may take a quick look in my on going installation thread located here: http://www.brultech.com/community/viewtopic.php?f=2&t=929&start=80

[Xathros]

2. If it only has two wires its not based on the Dallas 1-Wire sensor protocol. As it requires three wires positive, negative, data.

 

I don't believe this is necessarily true.  Some OneWire devices can run in parasitic mode where it only requires 2 wires (Gnd and Pwr/Data).  I think this configuration is more common when there is only a single sensor wired to a host (TStat) rather than when multiple sensors are used as in your case.

 

-Xathros

[Teken]

I don't believe this is necessarily true.  Some OneWire devices can run in parasitic mode where it only requires 2 wires (Gnd and Pwr/Data).  I think this configuration is more common when there is only a single sensor wired to a host (TStat) rather than when multiple sensors are used as in your case.

 

-Xathros

 

I can't honestly say I have ever seen data being sent on the power line. The other method I have seen is when the host (master) is not being used to supply power either because its not strong enough or the wire run is too long causing a voltage drop. This is where an axillary power source is used but the data / negative lines are still tied back the master.

 

Also, not to confuse others there are so called one wire systems but they are not based on the Dallas 1-Wire standard protocol. This may be what you're speaking about and they may very well be capable of using only two wires. 

[Xathros]

I can't honestly say I have ever seen data being sent on the power line. The other method I have seen is when the host (master) is not being used to supply power either because its not strong enough or the wire run is too long causing a voltage drop. This is where an axillary power source is used but the data / negative lines are still tied back the master.

 

Also, not to confuse others there are so called one wire systems but they are not based on the Dallas 1-Wire standard protocol. This may be what you're speaking about and they may very well be capable of using only two wires. 

Nope.  I was referring to the DS1822 sensor.

 

From the spec sheet:

POWERING THE DS1822

The DS1822 can be powered by an external supply on the VDD pin, or it can operate in “parasite power” mode, which allows the DS1822 to function without a local external supply. Parasite power is very useful for applications that require remote temperature sensing or that are very space constrained. Figure 1 shows the DS1822’s parasite-power control circuitry, which “steals” power from the 1-Wire bus via the DQ pin when the bus is high. The stolen charge powers the DS1822 while the bus is high, and some of the charge is stored on the parasite power capacitor (CPP) to provide power when the bus is low. When the DS1822 is used in parasite power mode, the VDD pin must be connected to ground.

 

-Xathros

[io_guy]

Parasitic mode is completely legit for one-wire.

That being said, floor heating uses resistive sensors (10k) similar to thermostats. I've also seen some use RTDs.

[Teken]

That's interesting to see and in the OP's case does open the door to that possibility. I am more familiar with the DS18B20 / DS18S20 1-Wire variety.

[io_guy]

Virtually all one-wire including the S/B20 support parasitic.

http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf

 

You likely haven't seen it because it is difficult to make stable over bit-bangers (Autelis and CAI).  Much easier with a hardware controller.

[deirwin]

Teken, thanks again - and wow on your system.  It will take a few days to look through it all.  

 

I'm just not sure if I should hook up a z-wave thermostat with an aube adaptor and no sensor.  Maybe i should just use a standard radiant heat thermostat and wait for technology to advance in that community.  it'd be very disappointing to have that one aspect of the house be excluded from my automation system...

 

I'm really surprised that more people are not doing this, or demanding this.  Radiant heating is coming on strong and is big in new construction and remodels.

[Teken]

Teken, thanks again - and wow on your system.  It will take a few days to look through it all.  

 

I'm just not sure if I should hook up a z-wave thermostat with an aube adaptor and no sensor.  Maybe i should just use a standard radiant heat thermostat and wait for technology to advance in that community.  it'd be very disappointing to have that one aspect of the house be excluded from my automation system...

 

I'm really surprised that more people are not doing this, or demanding this.  Radiant heating is coming on strong and is big in new construction and remodels.

 

Yeah, the install thread is pretty long and is a culmination of many years of effort and slow progress in various areas. Take your time to read over just that link about the Autelis Bridge. Its a fantastic product that offers so very much with very little investment when compared to other devices on the market.

 

There are other 1-Wire products which require a little more tinkering and support. I opted to go the route of plug and play because I am sure you can relate. At some point you simply do not have the time to baby sit or have another make work project that requires endless reading and set up time.

 

I have enough Alpha / Beta projects under my belt and didn't need another!

 

There has been lots of improvements in the original Autelis Bridge based on my feed back. So if you go that route you can thank me for all the new features! HA   

 

With respect to your original goal of monitoring the in floor heating and controlling it. I believe it comes down to first understanding how your device operates and seeing how something can be interfaced with it. I believe the first step is to see how the system reacts when power is removed.

 

If the unit powers up and retains its original temperature settings you may be in good shape. At that point you could use a Micro Relay to shut off the system during none occupancy periods such as sleep, work, school, etc.

 

I would humbly suggest you write into the maker and ask them for more insight and they may be able to first tell you what kind of sensors are being used and next what other alternatives are available for 3rd party TSTATS.

 

Again, I don't believe a 3rd party TSTAT would be the correct solution for a in floor heater. As it has no method to measure the floor temp and the ambient air temp would have to get very hot given its height to turn on / off. Keep us all in the loop as I am sure your project will find good use to others walking down the same path. 

[deirwin]

Well, I hooked a Z-wave thermostat without using the sensor on one system and non z-wave with sensor on the other.  They are both warming up nicely.  I will play with them for a little while, but I'm feeling like we would be better off with z-wave, even without sensor. Since they are both in bathrooms, what we really want is a cozy floor under our feet.  Maybe programming within a degree or two for on/off once i figure it out.