a little perplexed

ElderGreen

My brother has a tarm wood boiler in series with his weil mclain boiler. recently done. weil mclain boiler also weas used for hot water via the tankless coil. now he uses the wood boiler as the primary source of heat. the oil burner on tghe weil mclain has been shut ott manually. so there is no fire in the weil mclain at any time, and firomatic is closed going to it. but he still gets hot water out of the tankless coil even though there is nothing firing it.  i checked the water temp coming out of the wood boiler going to the non-fired oil boiler and the temp was 250 deg f. I'm thinking just the heat of the heating water circulating through the unit is heating the tankless coil.  Is this possible?

Zman

250?

Yes the wood boiler piped in series is heating the other boiler. The unfired boiler is adding much needed mass to the wood boiler setup. 250 degrees is way to hot for a residential heat system. Are the T&P valves intact?

Carl

nicholas bonham-carter

250 degrees!

What was the pressure reading in the system? Was it at steam bomb level?--nbc