"normal" limit setting

Jimbo_5

Have a 1978 CG3 Weil Mclain series 6 boiler.  It heats a single pipe fintube system loop, one floor, 55' long, 20' wide.  There are 2 of these boilers, side by side, one for the 1st floor and 1 for the 2nd.  The question is, one  limit switch is set at 200 degs and the other at 160 degs.  I suspect someone has touched the settings.  But what might be considered "normal"?  And is this a problem?

Mark Eatherton

180 degrees F

is atypical design temperature, but have seen required temps as high as 210 degrees F.



Start at 180.



ME

Paul Fredricks_3

questions

Do you get hot water from a coil in either of these boilers? If so you need to maintain temp for hot water production. Other than that, I go with the lowest setting that works. The two settings need to be at least 20° apart. The low setting is the temp the boiler will maintain when it's not calling for heat. The high temp is the temp the boiler tries to achieve when the thermostat is calling for heat. The warmer it is outside, the lower you high temp can be. Of course, you don't want to run downstairs every day to adjust temp, so you set the high to keep the house warm on your coldest day. I'd start at 180° and work your way down, but I wouldn't go below 160° for the high.



If you are getting hot water from a coil in the boiler, that will probably dictate the low setting, so you get enough hot water. Then the high needs to be 20° above that.