Furnace Hi-Limit Safety

Devan

Reading the very sad news Dan has on the site about the deaths caused from overheating.

I wonder if there is a Hi-limit temperature setting on the furnace, in case the thermostats malfunctions and stays closed??

Tim McElwain

All furnaces have

a high limit usually set at 200° (F) to open and shut down the burners.



A lot of the new furnaces have "Self Healing" feature which means the fan and also sometimes the combustion air blower will come on any time a limit opens.

Devan

Right

so how can two perish from an overheating in a room, suspect, malfunctioning furnace.

Not CO, overheating?

Tim McElwain

I would ask Dan

as I am not familar with his article. Where did it appear?

Devan

News Article

Here you go, I should have posted it before:



http://www.heatinghelp.com/news/article/59/Twins-die-when-heating-system-malfunctions

Tim McElwain

It doesn't state

what kind of system it was. I have seen electric heating systems do this but typically not something gas or oil would do that. It could happen if the gas valve stuck open but very unusual especially with dual seated gas valves used today.

Devan

True

but I did make the assumption since the article states there were two seperate units, one on the lower level, and one on the upper level wheret he boys slept.Doubt it was two boilers, in Georgia,

Tim McElwain

You are correct

it is probably a warm air furnace, heat pump etc type system.



Bottom line always check to make sure systems shut off on the safeties.

Devan

Good point

As part of annual check up, check to make sure system shuts off.