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Tridicator Gauge Failure-Again?

Sorry if this has been covered.  I did a search and couldn't find anything so I figured I'd ask:

When I repiped all my circulators and indirect last Spring I installed a tridicator guage on both the supply and return of my boiler.  One gauge began fogging up immediately after install, the other about 2 weeks later.  I figured oh well, bad batch/too tight/dropped or something so I pulled them and plugged the hole.  Recently I finally changed the boiler and figured now was a good time to replace them.  Different model but same result.  One of the gauges failed immediately (fogged up and didn't register a temperature change) so now it must be me.

I DID NOT over-tighten them,  1/4 turn until they stopped leaking then 1/4 turn more. 

I didn't use tape, only very little dope.

The end of the probe is EXACTLY where it should be, maybe even a little pulled back from the middle of the tee so I know its not bottoming out and damaging the probe. 

What the heck am I doing wrong?


  • Ron Jr._3Ron Jr._3 Member Posts: 594
    edited July 2010
    We've been having bad batches of tridicators

    Some register many psi right out of the box . Some have temps off the chart when it should read ambient . These are the ones that come shipped with the boilers we use . I'm assuming they're not the highest quality .

    One thing I found the hard way was not to hand tighten it from the face of the tridicator , it could send the psi side out of whack . Always use a wrench on the shaft .

    A good quality tridicator from a plumbing supply is a good bet . Sorry I don't know brand names though . Hopefully someone will chime in .
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    I used a different brand

    I bought them 4 months apart. Installed into a tee with room to spare. Used a wrench and did not over-tighten. What the heck?
  • Ron Jr._3Ron Jr._3 Member Posts: 594
    I feel your pain .....

    I'm out of spare tridicators to replace the bad ones that come with the boiler ...... It don't happen often , but we replace 2 to 3 boilers a week . If 1 out of 10 are bad and you're waiting for stock or a replacement under warantee .......... 

    The brand that comes with the Weil Mclain seems to be a good gauge . I'll find out who makes it is on Monday and get back to you  .
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    Am I doing something wrong?

    Dope on the threads. Is the guage fouling? I could see why that would mess with the pressure/head but not the temp. Also, it wouldn't explain why the gauge is fogging up.
  • Ron Jr._3Ron Jr._3 Member Posts: 594
    edited July 2010
    I've found them to fog up

    when someone hand threads the gauge all the way . But I've heard one boiler manufacturer in particular ships a gauge that more likely than not will fog up immediately . We use Teflon only and skip the first threads . But you're right , getting sealant in the gauge would only affect the pressure reading .
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    I guess I could pick it up with tongs

    move the boiler to a clean room, and use special water.
  • Ron Jr._3Ron Jr._3 Member Posts: 594
    edited July 2010
    Just trying to help there , buddy

    Of course you have to START threading in the gauge by hand ........

    But if you put too much pressure on the face of the gauge when tightening , funny things can happen to the gauge .

    I wasn't there to see how you installed these tridicators . So I'm going on your word there . Could be you just got unlucky with a bad batch .

    Have a good day and good luck with your endeavour .
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    I appreciate the help

    I always lean towards operator error on a listed device.  I could accept it was once but now its twice, being even more carefull the 2nd time.  I'd think it was a bad brand if I hadn't used two different ones.  I'd think it was a bad batch if  I had a dozen of the same lot number of gauge in my truck.

    What's the odds of a failed gauge?  1 in 100?  That makes it about 1 in 100,000.  Time to play the lottery. 
  • hot_rodhot_rod Member Posts: 13,184
    tough to find a

    good quality P/T gauge anymore. Even the good old brand names seem to be selling poor quality imports these days.

    Consider a separate pressure and temperature gauge. You can still find quality pressure gauges, I like the fluid filled stainless case versions.

    And you can still find round or vertical, quality temperature gauges. Shop at HVAC supply places.

    Anymore, digital temperature gauges seem to be the most reliable. Either strap on the sensor and insulate over it, or buy a well to go into a tee, and slide the sensor in.

    Strap on thermistior seem to be more accurate than infrared guns, depending on the pipe surface.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Ron Jr._3Ron Jr._3 Member Posts: 594
    One thing I forgot

    And it's a pretty expensive upgrade ..........  a digital aquastat with built in temp readout . I heard one manufacturer will have an all-in-one digital aquastat / LWCO / pressure sensor ( with readout I think )  ..... in the near future .

    Short of that , Hot Rod's idea sounds great .
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    I've got the pressure gauge covered

    And all I really wanted was a easy-read temp gauge to tell me how well the supply and return were balanced, and whether I could maybe cut back on the pump speed via motor control ect. 
  • I just use,,

    these,, inexpensive and simple to read.
  • hot_rodhot_rod Member Posts: 13,184
    this is what you want

    this dual thermometer from Azel. It reads both temperature and shows the delta T with the push of a button. It has a small battery, good for a year or so, or it can be powered with 24V ac. Reads C or F if that is important. i have installed a bunch, no problems what so ever.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • shoudabeenaplumbashoudabeenaplumba Member Posts: 74
    thanks for the link

    That's just what I want.
  • zacmobilezacmobile Member Posts: 211
    bad tridicators

    I've run into at least 8 leakers this year, one I replaced and the new one leaked even worse. 2 different brands too, but mostly some no-name ones my local wholesaler carries, for their cost you would think they would be a little more reliable.
  • Bob Bona_4Bob Bona_4 Member Posts: 2,083

    this thread pops up, on the day I change my second Buderus tridicator. Stuck on -30.

    I love it how one has to waste at least two hours of their day, no labor re-imbursment, for what the factory dismisses as "just a gauge". So profitable. I laugh when I see the words "instrument" on the box. Too kind. And yes, I am bitter about that. 

    Give us decent gauges!
  • michael_34michael_34 Member Posts: 303
    I've been using Wal-rich with no problems...

    knock on wood though! : ) I also used the Caleffi, but it is not as sturdy as the Wal-Rich. My partner drop the Caleffi while still in the box and the pressure indicator never recovered.

This discussion has been closed.


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