thanks - we have a steam system now that we are completely scrapping because it's so inefficient and on one thermostat for the whole house -- so we're getting separate units for each floor, but since the basement has baseboard heaters that need a boiler, we were thinking of doing hydro-air for the first floor so we could heat the basement. but i get so many different opinions that it's confusing....and i wanted to be sure that i'm not running a huge boiler in the summer ineffeciently to just heat my domestic hot water.

You really do need to have a proper heat loss calculation (CSA F280 standard for Canada) performed on you house to see what capacity boiler you really need, which should neither be undersized nor oversized and should be the highest efficiency possible (over 90% efficient). What size and efficiency boiler are you replacing? Do you want an all-in-one integrated unit, radiant heat and full capacity instantaneous domestic tankless hot water? What type radiators do you presently have, large cast iron, baseboard cast iron, aluminum plate with copper tube? What water temperature water is required? How do you air-condition? I would suggest finding an experienced, accredited hydronic installer in your area. SR Here is a link that might be useful: Beautiful Heat (Canada)

The set up is working great and I love it. It's cool how the Logamatic 2107 regulates everything (out side temp. sensor is installed). At the beginning of the season, when just taking the chill out of the house, the boiler wouldn't run that hot. Just enough to warm the radiators. (I would say 100-130 degrees.) Because the outside air temp was not that low. Now that the outside air temp. is much cooler (even below 32F at times), the boiler runs hotter. (around 150-200 degrees.) But the temps. vary widely and these temps. are not absolute. When the thermostat calls for heat, the boiler doesn't turn on along with the circulator. If the water in the boiler is hot enough, only the circulator will come on until the boiler cools down enough to warrant the oil burner to cycle on. So the boiler doesn't needlessly make more hot water than is needed. Sometimes the oil burner wont even have to turn on because there's enough hot water for the cycle of the circulator. The circulator for the heating zone for the house does cycle on and off more often to keep a more constant even air temp. in the house (68 degrees). With the new digital thermostat I'm experimenting with CPH (Cycles Per Hour). You can set the thermostat to make more short on/off cycles or longer on/off cycles by adjusting the CPH. This adjusts how often the circulator cycles on/off each hour. I started out with 5 CPH and now I'm trying out 4 CPH. The boiler will run hotter when making hot water of course (indirect fired maintaining 140 degrees with mixing valve set at 125 degrees). Domestic hot water always takes priority (or you can change that default setting). Even if the house is calling for heat and you need hot water for showers or laundry or dishwashing etc. The circulator for the house will stop and the circulator for the hot water will run until the hot water storage tank temp. is satisfied. Then the circulator for the house will continue until satisfied. I have the Logamatic on "Late" mode. Meaning the domestic hot water production stops at 11:30 PM every night. It resumes the next morning at 6:30 AM. The water storage tank (Buderus ST-150) loses very little heat standing by and there is plenty of hot water stored. So no real need to keep water at peek 140 degrees if it's not being used over night. The system goes into "Night" mode at 11:30 PM also. This turns down the "heating curve" for heating the house (lower operating temp.) The system goes into "Day" mode at 6:30 AM, where domestic hot water is priority and made first if needed and regular heating temps. are back up to normal for home heating. All these setting and times can be changed on the Logamatic to fit your homes lifestyle. It's pretty cool learning how this system works.

"Also have mixing valves at each zone with out door reset. So you can control the temp of the water by the outside temp." This. The boiler needs to be sized for the design limits, and the rest of the time (actually almost all the time) is oversized. Using a boiler wit an indirect tank and a reset thermostat allows the tank to serve as the buffer between system size for the coldest hours and the actual needs of the house when temperatures are milder. The boiler heats the tank and runs hot enough to not be damaged. The temperature in the tank is controlled by a reset thermostat based on the outdoor temperature. The zone valve allow final tempering for each zone based on their actual requirements.