Boiler Water Temperatures

Very often we hear about water temperature concerns on both the domestic and heating side. Many contractors have experienced calls with domestic water temperatures that are reported as too hot. Examples ‘ in the care giving nursing homes where the temperature of the water is not to exceed 110 degrees or the homeowner complaining the water is just too hot. In these cases, the cause is generally related to some type of faulty mixing valve or a valve element that is in need of replacing.

However, what about boiler water temperature? Today as we reach out to lower the already high cost of heating, we must look at all avenues of conservation. In the case of the boiler water, we often find that the majority of the hydronic systems are set to operate at temperatures of 180 degrees or even higher in some cases. Most of the time the aquastat is set to the higher temperature so that we receive the maximum Btu’s per foot of radiation on a zero degree day. Many contractors will size a job based on a zero degree outside and 70 degree inside comfort factor because it has been a general rule of thumb for many years. Really though, how many days do we consistently see zero degree temperatures during the heating season? The real fact is that when the outside temperature is not at zero, we have in effect an oversized boiler. Just as an added FYI, the actual designed temperatures are experienced in upper New England only about 3-5 percent of the entire heating season. With that said and being energy conservative, it only makes good sense when installing a new boiler to add one of the modern controls that will automatically adjust the water temperature based on the fluctuation of the outdoor temperatures. There are several companies that manufacture controls that can balance the boiler water temperature with the outside temperature conditions. Many systems only require a water temperature of about 140 degrees to satisfy the home’s heating requirements, and the lower the temperature requirement, the less fuel will be consumed. This of course will lead to lower fuel costs, which, of course, is the homeowner’s main concern as oil prices continue to climb to almost unaffordable heights. I have noticed that in my own home with lower water temperatures the comfort level seems to be more noticeable. This I attribute to the zoning valves staying open longer providing a more even heat. The customer may also notice less burner cycling and lower noise levels also. I know from experience that it is not easy to sell some of these controls, so it is extremely important to spend the time to explain to the customer the real value for the money they are being asked to invest in the new system. Boilers are becoming much like the automobile, the more bells, whistles and glowing lights, the more interested the customers become. After all, how many cars do we see being sold without CD players, power windows, heated seats and GPS? Also, keep in mind there are energy saving controls that support fuel conservation that will meet most any customers budget. These controls can be added to systems that have been installed for many years and some come with a guarantee a savings of 10 percent in the reduction of fuel.