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intermittem problem ..argghh (s milne)

ScottMP Member Posts: 5,884
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  • ScottMP
    ScottMP Member Posts: 5,884
    O.K. guys HELP !

    We got a call froma customer how had no hot water. we wnet over and found a Valliant GA100-16, ( no, thats not the problem Ken ). It is running a Hot Stow Indirect, this is a stone lined tank with a small coil in the bottom. The customer had shut off the boiler and then turned it back on and had hot water.

    We did a complete clean on the boiler and flush the coil in the tank. Since I had a feeling it was a end switch problem we changed the flue damper.

    Two days later the same problem. Problme was she had cycled the unit and its tough to trouble shoot after its been done, so we told her next time don't touch it and call.

    We went over last friday and the end switch on the zone valve had not made. Ah HA, we changed the head and .... got a call today that it happened twice over the weekend ( she' getting good at tuning it off/on.

    We have five zone valves, two V8043F-1036 and three V8043E-1012 running off two transformers which are both putting out 24 Volts.

    Main control is a Honeywell L8148 E.

    After shutting off from making Domestic the temp in the boiler runs pretty high, about 210. Does the L8148A have an intrical high limit that neds to be cycled to reset ??

    Help me Mr. Wizard !! Or at least Tim.


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  • S Davis
    S Davis Member Posts: 491

    Is the system using the 8148 to power any of the zone valves? I have had systems that would pull in the relay intermitantly because of a low voltage condition, check to make sure the internal trans isn't overloaded.

    S Davis

    Apex Radiant Heating
  • clammy
    clammy Member Posts: 3,094
    things to check

    Did you take a look at the aquastat controller for the tank ,see what the temp is at in corresponce to the domestic water temp,had a call simalar to that this week end ,chk your water temp at a facuetcould be a faulty tank aquastat good luck sure you,ll get a handle on it peace
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • Dingo
    Dingo Member Posts: 38
    Don't have my books here...

    but without checking on the 8148 it cedrtainly sounds like a failing limit. Now, one thing I can tell you is that I believe those Valliant boilers DO have an integral ECO attached to the probe on the aquastat control. So n.. putting 2 and 2 together - I'd say your on the mark.

    But the amazing thing is ... all the pros jumping on this problem -- all after hours. Guys working late to solve a problem. How do you explain those costs to a customer?

    Peace bro,

  • Mitch_4
    Mitch_4 Member Posts: 955
    24 volts

    You may be getting 24 volts, but what is the VA rating of your transformers. check the amp draw of the complete system,and make sure one of the transformers wasn't replaced by someone else who had a 20Va and you need a 40.

    My $0.02
  • tim smith_2
    tim smith_2 Member Posts: 184
    intermittent lock out

    I am betting on the ignition system. Either dirty pilot, poor ground or Defective ignition module. The latter being the most likely. I don't think the high temp side safeties with put it into lockout causing a need for reset of power. Clean pilot and check ground, test microamp readings for proper current. If it locks out again, change ignition module. Good luck, Tim.
  • Dale
    Dale Member Posts: 1,317
    tattle tales

    Any high limit that can self reset can drive you nuts. On this one I would wire a tattle tale flag device accross the normally closed limit to see if it opens while you are not there. Is there a water softener or anything else on the 120v feed to this heater? And of course make sure the ground is constant from the heater to the panel, a separate green wire is sometimes added if the ground is a conduit connection. As to the volts, see what the valves read under load. With some brands of heaters changing the ignition module is the next step, the wholesaler of your unit will know, good luck.
  • Weezbo
    Weezbo Member Posts: 6,232
    just listening .......

    sounds like the high limits need to be dialed back,try a setting at 170¡ãF ....you needent run the triple off the high limit either ...it will run off the lower limit just fine.
    the other side question is angle of the dangel on the transformer zone valve lash up... not only are the power function affected by the draw of the devise the lengths of wires and thier size can come into play as well.however having said that i dont think that is the problem...i have seen this ...the cover on the aquastat can stick the contactors causing loud humming or CHATTER that (now here i go playing honey well tech rep again :) ) can be repaired by taking the cover off ,turning off the power,moving the board in the "can"over to the left ,and tweaking the hold down "Tits" in the corners of the box. for whatever reason some of the boxes make it to us, the consumer, slightly different than they left the factory...
    the water maker adds probably nothing more than an end switch ,if you think it is the cause ...here would be my plan,taco sr501,isolate it completely from the equasion,let it function as a stand alone system,running off the SR501 opening and closing a zone valve off its end switch at the water maker,making and breaking the water makers recirc pump..the boiler will react when it cools down with no electrical whatsoever involved with the boiler . the temp probe sences the temp change and fires the boiler.
    If that dont fix it ....Then there is definite problems and one of which you may find in the first operation we disscussed ,Look on the back of the board if there is a burn look to the back of it then maybe the K-1 relay is smoked. .....
    Replace it.
    the 3aquastat that is,very few field remodelings on honeywell controllers these days it isnt like when we could take pieces in and out, now, you just exchange them and they send them back to the factory for the glue factory where they give them a decent burial and determine why it *#!@** up on the customer in the first place.
  • ScottMP
    ScottMP Member Posts: 5,884

    This is a standing pilot, but thanks for the input.

    These are the ones that try our patience, and make us say " I should have been a accountant" :)


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  • Mike Kraft_2
    Mike Kraft_2 Member Posts: 398
    replaced head


    You say the end switch wasn't making.You replaced the motor only?You may have a bad micro switch on the end switch.Also the cam may not be striking the end switch every time.As far as the temperature rise to 210 degrees......are you looking at the gauge.Not the best measure of temp.They are known to not be accurate.

  • ScottMP
    ScottMP Member Posts: 5,884
    Thanks Cheese

    we are leaning towards replacing the entire valve, body and head.

    Chris definatly found the end switch on the zone valve not making so he replaced the head. We are discussing what to do. Chris is leaning towads the possibilty of a bad head out of the box and I feel it may be ( as you say ) a problem with the whole valve not allways closing al the way and making the end switch.

    Thanks all


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