Advice on thermostat needed

Hi all,

I've been on this site for some time now (about a year or so) but this is my first post.
Last year, I was in the process of building a new house. I started in May, and moved in with my family in November. The house is about 240m2, and has a basement of 80m2 and about 160m2 of living quarters (a living room with a kitchen and a diner) on the first floor and 4 bedrooms on the upper floor. For heating and cooling, I chose an Aermec chiller with heat pump with 16kw of heating power (model ANZ0507HA). The chiller is equipped with a Copeland scroll compressor. For backup, and during really cold days, I also have an electrical heater with capacity of 18kw, but this was rarely used (only when the temperature was really low, below -5C, the electrical heater was helping a bit, bringing the temperature back to the required 43degrees C, which I chose to be the operating temperature of the system. In those conditions, the chiller was able to heat the water to around 34-35 degrees C, before the electrical heater turned on. On the lower floor, I have 5 loops of UFH in the entry hallway, the kitchen and the diner (around 70m in length each), and one FCU in the living room, and on the upper floor, I have 4 FCU in the bedrooms, 1 medium sized radiator in the hall, and I also have 2 towelracks in the bathrooms on both floors. For the UFH, I have a 3-way mixing valve that reduced the water to 35 degrees C.
I was very pleased with the system and the way it performed this winter ( my electricity bill was within the range I anticipated) and the system worked great. (during December-January, the temperature was mostly around 0 to -2C during the day, and -6 down to -14C (rarely though) during the night. However, during the month of February, the compressor suddenly broke down, and I had to switch to my backup electric heater. The installer came to see and concluded that the compressor has failed and it needs to be replaced. As the chiller was still under warranty, they replaced the compressor at no charge. During that period until the compressor was to be replaced (about a month), I realized the difference between heating the house with heat pump as opposed to an electric heater. The bill for that period (March) was about 2,5 times bigger, and I am comparing the months of January and March, which is way warmer. When I asked why did the compressor fail in such short period of time (about 4 months of operation) I was told that although they had installed over 100 such units in the last couple of years, this was the first time they had a failed compressor. I hope they're telling the truth.

This was a rather long intro, and now for the initial reason for this thread :)

During the winter, I had the system up and running 24/7, which was not needed most of the times. For example, during the day my wife and I are at work, and our children are in kindergarten, so nobody is at home, but I had to keep the system working in order to have warm home when we return. Can I have some advice as to what kind of thermostat I can install in order to run the system more economically, and to be able to set certain parameters for the system to switch at certain periods in different modes. For example, I'd like to be able to reduce the water temperature during the night to, for example 35 degrees C, but then to be able to increase this temperature automatically 1 hour before I get up for work, and then, when we leave for work, the system switches off, and then back on before we return from work. I had this setup for my apartment couple of years ago, which was heated with an electric heater and radiators only, and this worked great, but I don't know how to do this with this system. The chiller has a micro processor built in, so it's not really convenient to run in the backyard to adjust the temperature daily, or even couple of times a day especially when outside temperatures are sub-zero. I have an option for a remote controller from the manufacturer, but it seems a bit overpriced (about 600 euros), and more importantly, it doesn't give me an option for timed programming, or even internet or telephone controlling. Ideally, I am looking for something that I can remotely control (either via telephone line, or even better, via internet). I looked at the Trane TZEMT400AB32MAA Remote Energy Management Thermostat, which runs for US $150, which combined with the Schlage Link System, would allow me to remotely control, but I am not sure whether this would work with my chiller. Once again, its an Aermec ANZ0507HA, of the Italian manufacturer Aermec.

Does anyone have a good advice on this matter, how can I make this work. I am sure that by smart controlling the power of the heat pump, I can save additional 10-20% on the electricity, and that's not bad.
If anyone has any questions about the system, I'll be glad to answer.

Cheers,

Jordan

You don't need to reduce the water flow temp -- just turn down the required room temperature for the times it is unoccupied...simples :)

Any programmable thermostat will do the job.
just google
http://www.honeywell-thermostat.com/heat-pump.html

Hi ATC
Not sure where Skopjeis but it sound very cold. It sound like what you want is a Home Automation System. There are many new ones on the market recently, with a google search you should find many. But is that what you need is the question. You will be able to communicat via txt or internet and maybe have some graphics of the system on your computer. These are not cheap thoough. Another way is to use a simple programable controller and add components like txt and web link.
First things first is you need to find out what parameters you can control on the chiller like water temp reset function. Start and stop should be standard. you may even be able to pick up various system temps and other points from the chiller.
Next will be to set up the system. To do this you will need a little trial and error to find out ... Dependant on the ambiant temp how long it will take to heat the conditioned space to the required temp. Normally the underfloor heating is a little slower than air heating. You could even zone different ares in the house and switch them on/off depending on usage times. Or you may have semioccupied times, as oppesed to switching it off completley you may allow cooler temps via tstat settings automaticly durring unoccupied times.