I have a Burnham V73T oil fired hot water boiler with a tankless hot water system. I have to purge the 3 zones once a year due to gurgling in the baseboard. I recently purged the baseboards and shortly after that I noticed that the amount of domestic hot water is reduced, 1 - 1 1/2 showers. I don't know if the reduced hot water is related to my purging, or just a coincidence. Could purging of the zones have caused the reduction in domestic hot water? What are potential causes of the reduction in domestic hot water in a tankless system?
I have now looked at the hot water controls and they are set as follows: Hi=190, Lo=170 and diff is set at 10. Looking at the manual for this burner these appear to be the settings for a steam boiler, not a water boiler which is what I have. The manual states that the settings for the water boiler should be: Hi=210, Lo=190 and diff is set at 25. Would there be a reason that the installer set these lower limits? Is there any potential harm by raising these limits? Is my assumption correct that my heating costs will go up with these higher settings? Significantly?