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steam boiler with power venter

Hi everyone-

     Was on a steam boiler no heat call today.  It was actually a simple fix, boiler was flooded and the 24V transformer for the LWCO and auto feeder controls was shorted out and the customer had fed the boiler with it still hot. Didn't want to take up the customers time figuring out the birds nest of wires, but it got me thinking about how the power venter was wired into the controls with the 2 transformers. Most of the steam boilers in my area are vented into chimneys.  Obviously it has a relay and pressure switch that closes and sends power to the other controls and gas valve. I'd assume something like this:  power from transformer---> thermostat---->power venter---->LWCO---->hi cut out/low cut in----gas valve.   What I'm also wondering about is if the second transformer was just for the call for water circuit (3 and 4) from the old float style LWCO with 4 terminals because the boiler fired even with that transformer out. (but the boiler still shut off on low water when I drained the system)




  • Charlie from wmass
    Charlie from wmass Member Posts: 4,285
    edited March 2010

    maybe on the line voltage.
    Cost is what you spend , value is what you get.

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  • billtwocase
    billtwocase Member Posts: 2,385
    makes no difference

    steam, hot water, or warm air, the power vent will and should be wired the same. Burner wired thru a fan proven switch, and a blower post purge of 3-5 mins. The power vent is called into action only when the burner is powered, and should have a seperate power source to complete the post purge cycle when high limit, pressure trol, or thermostat is satisfied. These are rarely wired properly. I know this by correcting them as I go.  peace
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