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The shakes

geezer1 Member Posts: 2
Can anyone tell me why a Weil-Mclein GV-6 gas boiler would start shaking during the flame on cycle only?  Hydro air system with 3 air  handlers and filled 50/50 with Cryotec.  Installed in 2002..started shaking 2 seasons ago.  Tried replacing both circulators, new cryotec, new blast cone, new relief valves and exp tank?

Any ideas??



  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    Flashing to steam?

    When it is rocking and rolling, look at the T&P gauge and see if the needle is bouncing. If it in deed is, you're flashing to steam, which is common in systems with glycnoids in them.

    It is usually more of a problem with On/Off boilers versus modulating boilers, but can be a problem in either. As for a solution, is the glycol really necessary? If you re-pipe the boiler primary/secondary, and pump away from the expansion tank, but towards the boiler (watch the pressure drop) you can suppress boiling.

    I have little experience with the W/M line, but it is just another heated vessel...

    Watch the gauge, and get back to us.

    Oh yeah, I forgot one possible solution, that being to add a chelate to the fluid. I have used that successfully on large (1.5 mil) copper fin tube boilers being used on snowmelt systems and heard the noise silenced IMMEDIATELY.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • geezer1
    geezer1 Member Posts: 2
    Shakes - Part II


    The pressure needle is bouncing like mad when it is firing.  I asked a friend a while back (who is a plumber) what he thought, and he said it might be a "dry spot in the boiler", like maybe a defect in the casting.  So when I called W/M, they told me it was highly unlikely, and it probably was lime deposits. If I wanted to change the boiler, thenm take it to the supply house where the area rep would smash it apart to determine if they would replace it.  Sounded a little to much like a gamble to me, and after working great for 6 years and charged with Cryotec, I'm pretty sure it isn't my water supply.

    The only other unusual thing I can tell you is that the rubber insulation on one of the cellar air handler coils (supply side) is rotting away, and has left a big pile of crumbs on the floor.  I don't see it leaking, but something weird is going on.  The boiler runs all summer for the storage tank, and it never shakes then.

    Thanks for the advice..this time of year, the banging is so bad it wakes me up.

  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,552

    We had a similar problem with a W/M oil fired unit, don't remember which one, probably a Gold. I don't think it was bouncing, but was very noisey on the water side. No antifreeze. W/M suggested we pump muriatic acid through it. We told them no thanks, not interested in dealing with this very corrosive acid or disposing of it afterwards. We also tried a chemical additive, but to no avail. If I remember correctly we changed out the boiler.

    We also had a Burnham RS-117 that was bouncing like you described. The solution was a 005 piped between the supply and return and running 24 - 7. Problem solved. I guess there wasn't enough flow through the boiler.
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