Outdoor reset, and how low a temp can I operate a Burnham V8 cast iron oil boiler without condensati

VelvetFoot

I have a Tekmar 256 outdoor reset control coming in the mail.



One of the settings is ‘minimum boiler temperature’, and the odr manual says ‘consult mfr’.



Besides just setting the minimum temperature for the odr control, I’m thinking I could tweak the settings on the outdoor reset so that the boiler operates generally at lower temps, except for the separate zone for dhw (cold start boiler), which is also on priority.  The insert heats the downstairs quite well, so the boiler is, in effect, oversized by 2 (already have a smaller nozzle).  I’m thinking lower water temps going through the fin and tube baseboard convectors could not only allow savings with lower temps but maybe longer run cycles.  The Tekmar manual says normal range of operation of fin/tube baseboard is 140-180F, but how low can I go without damaging the stack or boiler.  How could I even tell?  Water under the boiler?  I figure the domestic hot water loop coming up to 180F periodically would mitigate some.  I’m pretty sure the stack itself is stainless, but the connection is galvanized.

Could I go to 130F?  Lower?



Thanks very much.  I will continue searching.  Much good info!

CMadatMe

140 degrees

Is minimum return water temp back to the boiler. Once you drop below that you take the chance of cracking a block and once below 135 the chimmney will begin to condense another no no.

VelvetFoot

Thanks

Thanks Chris