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New Lochinvar install. Primary Loop Delta T question
Just wanted to thank everyone here for all the great information posted on this site. I've been loitering around the site while installing a new boiler and the info I've found here has been invaluable.
I just finished an oil to gas conversion in my 2300 sq foot single level ranch. I installed a lochinvar KHN110....over sized....I know! Started with the recommendation of a friend who is a "Professional" and wanted me to install a KHN155. I knew it was more than I needed and went for the 110. After spending some time here I realized that I should have spent some more time researching! It does not seem to short cycle at all (still mild here in Rhode Island), just cruises around 15-30% depending on how many zones are calling, so i guess i will get by with it. I will post some pictures of the install for some constructive criticism!
I am in the process of fine tuning and dialing my outdoor reset back as far as possible.
The system is plumbed primary/secondary, zoned with circulators, 3 zones, baseboard radiators. I installed a Nimbus speed control for the boiler pump so that I could utilize the boilers ability to control the boiler pump speed using the 0-10v signal. The factory default setting for the boiler delta T is 20 degrees, and it maintains that 20 degrees perfectly. I was wondering if anyone had any recommendations for what delta T I should set. The only info I can find is from a lochinvar newsletter that basically says too much flow can cause erosion of the heat exchanger. Too low of flow can cause scaling of the heat exchanger.....though i'm not sure if this even pertains to the KHN Fire Tube boiler. I am also wondering if keeping the delta T lower might increase efficiency as the whole heat exchanger has a better chance of being in the condensing range.
Any input would be appreciated! Pics to follow (if i can figure out how)