Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Alternatives to Honeywell Vaporstats?????

I just installed another New Vaporstat and it was acting flaky.  Checked voltage across the microswitch and read 24 volts on the input and about 14 Volts on the output.  I think this is now 3 out of the last 5 have been defective.  Usually I found they would not recycle after the first cycle...but never checked the voltages.

I am looking for a reliable alternative... any suggestions?  The only choices I know of at this point would be electronic units with Pressure transducers.... a bit pricey but alot cheaper than having to reinstall poor quality current models.
The Steam Whisperer (Formerly Boilerpro)

Chicago's Steam Heating Expert

Noisy Radiators are a Cry for Help


  • David Nadle
    David Nadle Member Posts: 624
    Don't understand what you did.

    The vaporstat is a simple SPDT switch, and it's likely that only the common (C) and normally closed (NC) terminals are connected. The voltage across those terminals should be zero unless the vaporstat has cut out. In that case the voltage depends on the impedance of the ICM. By placing your meter across the open switch you have created a voltage divider at very low current. The ICM is dropping about 10V and your meter is dropping the other 14V.

    The normally open (NO) terminal is probably not connected to anything. If you are measuring C-NO or NC-NO those measurements are meaningless. If you're using a digital multimeter you are likely reading phantom voltage.

    It's simply not plausible that you're seeing a 60% defect rate. I respectfully suggest that maybe something else is wrong...
  • Measurements

    The measurements were taken between each terminal and ground, not between the terminals.  Once the control was out of the operating circuit the boiler ran normally.  Previous failed vaporstats would simply not reset after going off on limit. 
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • Same problem here Boilerpro,

    I tried every-which way,,, no go.

    Ask Gerry Gill what he thinks,, he was "ticked-off" too not long ago!
  • gerry gill
    gerry gill Member Posts: 3,000
    i feel your pain..

    the terrible operation of the modern vaporstats is what led Steve to come up with the Pajek Pressure Controller come the original black vaporstats were so good? are todays devices supposed to be ''new and improved'' hehe.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Bad vaporstat microswitch

    I worked for the post office as a technician on the mail sorting machines. We used a lot of microswitches and estops on these machines on 24v circuits. These switches would invariably get flakey over time and the problem was dust and corrosion. The switches would work forever at 120v but were not reliable in the 24v circuits.

    This means the contact plating may be sub par or the switch has no wiping action (helps keep the contact clean). There are not many designers left who know how to design a mechanical switch for "dry" circuitry (low voltage and current). I'll bet the switches are from China.

    If you can try one of these defective vaporstats in a 120v circuit it would be interesting to see how it performs. I'll bet they work just fine there.

    Since these are primary safety controls I wonder if we could use the threat of government oversight to force Honeywell to take some action on this?

  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,422
    was there any feedback given?

    to this earlier thread?

    maybe they only test them on 120vac, instead of 24 vac.--nbcgerry gill gerry gill November 25, 2009 @ 5:02 PM

    Contact this user Okay guys, here is our chance to make a difference..I talked with a gentleman who knows some of Honeywells engineers, and he is willing to take our issue with the vaporstats up with them, but what we need is documentation on specifics..thats all they will listen to..they won't react if we just sound off, tho they if you could write up any instances of vaporstat problems preferably on your letterhead and e-mail them to me i will forward them on with my specific, such as model # such in such when set to 4 ounces actually was triggering at get the picture..okay guys..send them to me at [email protected] Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.G.W. Gill Plumbing & Heating
  • Thanks.....

    I remember somebody had made contact with honeywell, Now I know who!

    I will try to gather specifics, but for now, any  suggestions for alternatives?
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • Jamie Hall
    Jamie Hall Member Posts: 15,339

    it was government oversight which obliged Honeywell (and others) to abandon the tried and true and reliable mercury switch, IMHO it is hopelessly optimistic to expect more government oversight to fix the problem...

    As NBC noted above, the best way to handle this is to document the problem -- completely (how many cycles?  what voltage?  what pressures (real pressures)?  etc. etc. to Honeywell, and let them get on with it.  Keep in mind, though, that the fix will almost certainly involve greater expense, so don't complain when it does.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Expense.....

    Well, with so many defective units, it is already costing at least a couple hundred dollars for each installation due to all the extra costs related to shipping additional components (which I end up paying), paperwork  and the extra expense to rturn to a jobsite that is 4 hours round trip to replace the control. 

    What would really wake up manufacturers that have high defect rates is if they had to pick up this expense.   I don't know of many industries where everyone else is expected to pick up all the costs for defective parts. 

    60% defect rates for Honeywell components are not new... I've had gas valves and others thermocouples with similiar rates.
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • You must get the beasts attention

    I agree that the "authorities" can be a royal PITA but I was hoping the threat of drawing them in could get Honeywell to at least look at the problem people are having with the vaporstats.

    BTW the vaporstat on my system is a NOS mercury that bought off  ebay last fall. It is the newer type but has worked just fine - so far. It's setpoints are not as accurate as I would expect but repeats very well and that is all I care about.

    Lets face it, the mercury in a vaporstat is nothing compared to the millions of CFL's that get dumped into landfills every year. People in the trade are much more likely to dispose of a mercury vaporstat properly than the average homeowner who traet failed CFL's the way they have always treated blown lightbulbs.
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!