Another person seeking help trying to dial in their outdoor reset curve...
I had a Navien NCB240e installed in November 2017 replacing a 40 year old oil fired system. House is a 1900 sq ft. 1948 Cape with cast iron radiators. One zone covers approx 90% of the house (3 BR, 2 baths, LR, kitchen, DR, finished basement) and another zone covers a former breezeway converted to a four season room. There is also electric heat baseboard in a 1 room addition off the living room that was added in the 80's or early 90's. We only turn the electric baseboard heat on when someone is using that room. The former homeowner had Mass Save insulate and install new windows around 2010.
I did not know much about condensing combi boilers when I had the unit installed... just that it was the most efficient and recommended option from several installers. So I did not ask the right questions and trusted the contractor when he said everything was set up correctly and not to touch anything.
Upon further investigation the outdoor reset curve was installed but not activated. The space heating supply was set to 140 which seemed to work ok even during the bitter cold in the Northeast the last 2 weeks.
So I am now trying to get the ODR properly set up.
The below are the ODR settings I've used for the last two days where the actual outdoor temp has been between 0 and 20 degrees. The system is cycling on about once per hour for about 5 minutes at a time. (House is set to 65f) From what I've read in other posts that cycle time is not nearly enough? So my question is what input should I be looking to adjust? I already have the lowest outdoor temp set at the system minimum. I also noted when the system cycles on, the supplied hot water temp is close to 160f. Given the house was doing ok at 140f, it seems like this is obviously inefficient.
B: 3 (I know 6 is technically correct for my house but a previous post said to try 3 first)
C: -4 (Went as low as I could go and unit is keeping up fine. Currently 2 degrees outside Boston)
D: 60
E: 30
F: 100 (my guess is this is what I should be adjusting)
G-W: All at system defaults
Also, does this mean my system is oversized? I mentioned to the contractor that we would likely be adding a bedroom over the garage in the next two years and would like to eventually convert the electric baseboard onto the gas system, so I think he took that into consideration.
Thanks for any help!
I had a Navien NCB240e installed in November 2017 replacing a 40 year old oil fired system. House is a 1900 sq ft. 1948 Cape with cast iron radiators. One zone covers approx 90% of the house (3 BR, 2 baths, LR, kitchen, DR, finished basement) and another zone covers a former breezeway converted to a four season room. There is also electric heat baseboard in a 1 room addition off the living room that was added in the 80's or early 90's. We only turn the electric baseboard heat on when someone is using that room. The former homeowner had Mass Save insulate and install new windows around 2010.
I did not know much about condensing combi boilers when I had the unit installed... just that it was the most efficient and recommended option from several installers. So I did not ask the right questions and trusted the contractor when he said everything was set up correctly and not to touch anything.
Upon further investigation the outdoor reset curve was installed but not activated. The space heating supply was set to 140 which seemed to work ok even during the bitter cold in the Northeast the last 2 weeks.
So I am now trying to get the ODR properly set up.
The below are the ODR settings I've used for the last two days where the actual outdoor temp has been between 0 and 20 degrees. The system is cycling on about once per hour for about 5 minutes at a time. (House is set to 65f) From what I've read in other posts that cycle time is not nearly enough? So my question is what input should I be looking to adjust? I already have the lowest outdoor temp set at the system minimum. I also noted when the system cycles on, the supplied hot water temp is close to 160f. Given the house was doing ok at 140f, it seems like this is obviously inefficient.
B: 3 (I know 6 is technically correct for my house but a previous post said to try 3 first)
C: -4 (Went as low as I could go and unit is keeping up fine. Currently 2 degrees outside Boston)
D: 60
E: 30
F: 100 (my guess is this is what I should be adjusting)
G-W: All at system defaults
Also, does this mean my system is oversized? I mentioned to the contractor that we would likely be adding a bedroom over the garage in the next two years and would like to eventually convert the electric baseboard onto the gas system, so I think he took that into consideration.
Thanks for any help!