Hi.I currently have a 1986 Trianco oil fired boiler. I beleive the model is DB125. I've done *tons* of searching and have been unable to come up with any details on this unit other than the ID plate on the front which says it is 125000 BTU, 108000 BTU net and that it is likely a steel boiler.

I am in the planning stages for the addition of an indirect water heater. At the moment I am trying to properly size the circulator pump for the indirect zone. The problem is I need the resistance (feet of head?) for the boiler itself and honestly do not have a clue what to use for this in the calculation and doubt I am going to find anything in print for this boiler. As much as I like to do things right, I may have to just take a guess at the feet head for this boiler. I was wondeirng if anyone might know that what the typical feet of head resistance is for a 25 y/o steel boiler of this size?

Thanks very much for any insights you can provide