Thoughts on secondary high limit

bill_105

So I have a chat with a Tech. for the local gas supplier. We talked about the city of Anchorage's requirement of a secondary high limit switch. For the life of me a can't ever remember seeing a primary one fail and water blowing out the relief.The gas guy says that in their inspections only do they mention it the enforced building code parts of town. Which leaves me wondering, if it's so important why doesn't the boiler Mfg. put them on?

Big Ed_4

Secondary Limits

Have you ever seen a simple L4006A or L4081 creep up over time ? A plugged pigtail ? Capillary tube not fully inserted in the well ? A short in a wire ? Anything man made will fail . It's just a matter of time.... Most secondary limits are manual reset types ... Buderus Logamatic controls have manual resets limits already built into them .. Most manufactures don't add them because they don't have to .It's a money thing. .. Parts of the country in the NorthEast enforce secondary limits.... ...



Just a thought....Most codes where added on the books after someone already died....

Charlie from wmass

I would embrace them

Dead or homeless customers seldom give good referrals or pay there bills. I never saw the value in fighting safety codes .

World Plumber

Limit out of wack

I just dealt with a limit that decided to do it's own thing today. Just make sure they are in series and not parallel. I've seen that in a school no less they had the secondary limit but some idiot wired everything in parallel including a spill switch which kept the burner firing nonstop. Talk about a bomb waiting to explode.

meplumber

They are very common in the New England.

A manual resetting high limit is extremely important.  Even in non-code enforced areas, I do it for piece of mind.  Buderus, Viessmann, HTP, and others are including it in there boiler control packages. 



Worth the effort.  It only takes one failure to ruin your business forever.