How to control heated floors with HAI?

[pbeaulieu]

I have a ceramic tile floor that is heated by hot water. Currently, I have only manual control, I would like to automate and also have 2 zone for the heated ceramic floor.

1) Are there any temperature sensors for the HAI Omni Pro II that can fit down a 1/2 pipe?

2) Are there systems that can be controlled by the HAI?

3) Would an Omnistat thermostat work?

Any help or comments would be appreciated.

 

[Mike P]

Omnistat works great, I have radiant heat heat and thats what I use with my M1. No problems at all, I'm very happy.

Mike

 

[pbeaulieu]

Omnistat works great, I have radiant heat heat and thats what I use with my M1. No problems at all, I'm very happy.

Mike

What did you use as the temperature sensor?
Are you measuring the temperature of the floor or the air in the room?

Thanks,

 

[signal15]

What did you use as the temperature sensor?
Are you measuring the temperature of the floor or the air in the room?

Thanks,

I know this sounds like a great idea, but here's the problem... Most floor heat thermostats perform a calculation to estimate the heat capacity of the floor. With a regular thermostat, it would turn on the heat and continually heat the floor until the room temperature reaches the set point, and then shut off. The floor will be hotter than the room temp, and the temp of the room will continue to skyrocket past the set point. Then it must drop to below the set point, and the cycle starts over.

With thermostats made for floor heat, they will monitor how quickly the room heats up and cools down, and then make a calculation that will turn on the pump every 15-20 minutes for a period of time calculated to keep the temp in the room stable. For example, my garage heat in the winter turns on every 20 minutes for about 2-3 minutes.

What you need is a communicating thermostat that can talk to the HAI that calculates the heat capacity of the floor, and as far as I know, no one makes one. However, Aube does make one that you can remotely control to day/night mode. My day setting is 65F, and my night setting is 50F. It's just two terminals that are on the back of the unit, and when you bridge them it puts it in night mode. So it's a start, but it doesn't give you full control. For $45 though, it's not a bad deal, and if you're replacing a thermostat that doesn't do the calculations, you'll probably save this in energy costs the first month you run it if you're in a cold northern climate.

 

[AnotherOne]

I'm using my elk to control relays that turn on and off recirc pumps to heat my home. There's temp sensor or elk keypad in each of the twelve heading zones. I run a script on my PC that figures out when to turn things on and off based on the current outside temp, the temperature trend, the time and the amount of sun hitting the house (this is done via a temp sensor in closed black box on the south side of the house). It takes a while to get things tuned, but now everything stays within a degree of the setpoint except when we have extreme temperature drops - the heating system can't keep up - actually it's the transfer of the heat from the floors that can't keep up. The water running through the floors is between 120 and 130 degrees F.

 

[mtgoat]

Sounds like signal15 may be referring to the Aube TH135, which I can attest is very effective at anticipating and not overshooting temps. I have radiant underfloor, and it's the most comfortable house we've ever owned. If you're interested in giving it a shot, I have a couple sitting on the shelf (ended up combining a couple zones, so needed fewer than originally planned) which I'd let go at a bargain price.

 

[pbeaulieu]

Thanks for all the comments. I left out some key info about my setup. I heat the floor to take the cold edge off the tile. The room is also heated and cooled via a heat pump/gas HVAC.
So, currently the system measure the temperature of the ceramic tile floor and turns on/off the recirculating pump to keep it at temperature. The temp sensor is pushed through a 1/2" tube from the basement that goes up into the ceramic floor. Once the system is turned on it stays on for the winter season. The temperature controller is very basic and located in the basement. That's why I would like to consider an alternative setup that would hopefully work with the HAI. I've just started looking so we'll see.

Again, thanks for the comments and any others.

 

[mikeweber3]

Paul,

Elk makes a thermister that would fit your application. You could create some very simple boiler reset logic such as:

When outdoor Air is below 50 and above 30 run floor temp @ 85. When OA btw 10 & 30 95. When below 10 105.

Thanks

Mike

 

[Armagedon]

I'm using HAI temperature sensors with OmniPro II for controlling heated floors. One sensor for one room / loop. Temperature setpoints is possible to change via console or computer (SnapLink, Dealer PC Access software). I'm measuring air temperature in the room.
OmniPro II outputs are controlling floor heating water switches and heating water pump (which pumps heating water from tank to pipes).
No need for any additional systems to control. OmniPro II outputs are connected to relay module and via relay's are controlled the heating water switches (24V, 2W, made by Uponor).

 

[pbeaulieu]

Thanks everyone.

I have ordered an HAI 14A00-8 Water temperature Sensor modul which will allow me to monitor the temperature of the floor itself.

 

[fcwilt]

Thanks everyone.

I have ordered an HAI 14A00-8 Water temperature Sensor modul which will allow me to monitor the temperature of the floor itself.

That's what I used. Works fine for me.

 

[Mike P]

Hi, I posted to this a while ago. I have radiant heat with HAI stats and an M1 and all works fine(wife loves it). Now I am in need of a little advice. We now have a second home in Lake Placid, NY. It gets quite cold there at times. I am going to install radiant heat in the kitchen, just received the hePex and extruded alum. panels. I will be installing this using an electric hot water heater(electric very cost effective in the area). Has anybody here ever used an electric hot water heater to do this? If so any advice? I have no automation yet, but would like to leave all opions open(Please don't tell my wife). Any suggestions of how I can add to the system while in the building stage to simplify automation at a later date?

Thanks,

Mike

PS: The home has no insulation in the walls, will take care of that in the spring(built in 1906)

 

[pbeaulieu]

I have installed the HAI 14A00-8 and it is measuring the temperature of the ceramic tile floor (not the room).

I have tried to set the high and low setpoints but I have found that they have to be 4 degrees apart. That is going to provide to big a swing in the floor temperature. For example, if I want the floor temperature to be 68, I would like to set the low and high setpoints to 67 and 69 respectively. The floor changes temperature very slowly. Is there any way to do this? or am I looking at this the wrong way?

 

[fcwilt]

Well you don't have to use the set points - you can use just the reading that is checked at intervals and some action taken. The issue I think you will find is that the slab has a large thermal mass and that makes controlling its temp tricky.

 

[JimS]

Mike P,

I hate to tell you this since you already have the parts but if I was doing this I would skip the water. I did an electric install in our master bath (under a tile floor) and it is great! I did hot water (nat. gas energy source) for the floors in the basement but that seemed like a lot of trouble for the bathroom and floor height was a concern. Putting the water tubes under the subfloor is an option but harder to get the heat through the floor.

Is the floor tile?

Since you are using electric as the power source why heat water that then heats the floor (with pumps, etc)? Just extra losses in the water heater and lots of extra controls and things to go wrong.

I used the type with a coil of wire rather than the preformed mats. The mats might be easier on large open spaces but I found the wire easy to work with.

I didn't hook it into automation but that is really a separate issue and could be done.

An electric water heater can be used for floor heating. I used a gas water heater. It just wouldn't be my choice for this kind of install.