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new vaporstat thread

Thanks for the numbers for the new vaporstats (also notice that these new ones have 'obsoleted' the mercury swithes)

Quick test for the day. Whats the difference between the:




hint: don't read the blurb at the top, go to the specs.
hint to honeywell: check your syllabi to make sure they accurately describe the control.

For those who want to skip the quiz here are my real points on Honeywells offerings.

1. From an installers and homeowners perspective I can't see any great concern about having a few accurate mercury controls in a building. From the manufacturers point of view, it might be desirable to phase it out because they have to deal with a modest volume to make all these controls although they have the opportunity to create a better standard for dealing with those volumes.

Hope the new ones work as well and as long, I'm going to try to find a few of the old ones just in case, but to the difference between an
L608A1046 and L608B1131 which is analogous to the difference between the new non-mercury vaporstats, I'm surprised that the single throw version closes on rise. Do they use these similar to a low limit circulator or fan control. I would have thought that a single action would open on rise if these controls were predominately limits on system pressure.


  • They're used as fan switches

    Mostly on suspended unit heaters in garages and warehouses, that type of thing.

  • archibald tuttle
    archibald tuttle Member Posts: 1,085
    sorry wrong number

    fan control on unit heater, of course. I figured it was something like that although I haven't encountered this control strategy yet.

    BTW , the SPST mercury control is a L408B1131 (not an L608). Only Honeywell knows why and, insofar as I can tell, they ain't tellin.

    So the stock that is out there they charge about 15 bucks more, or about 8% for the SPDT option. For the life of me, with controls that probably aren't 'best sellers' I can't figure out why they wouldn't just make them all SPDT ( or DPDT for that matter). I suppose because people plugging into an old SPST install could screw it up by choosing the wrong terminal, protecting us from ourselves once again.

    But now that they are phasing out the mercury vaporstats, I can't imagine why they didn't consolidate the offerings meaning that supply houses could stock one control to serve both needs. Then more likely to find them in stock. My so-called heating supplier doesn't have either the new or old SPDT and I've been on hold for 10 minutes while they figure out how quick and for what price they can get one.

    At least their wholesaler came thru. 1009 $154.86 1046 $172.08 - 1 day delivery southern New England.


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