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

Williamson GWA 105 Series 2 boiler not keeping a steady heat

dcpace78 Member Posts: 3
edited March 2022 in Gas Heating
I have a Williamson GWA Series 2 boiler with the same problem as in this thread (https://forum.heatinghelp.com/discussion/164219/williamson-thermoflo-gwa-105-problems). 2nd time in 5 years, heats to 180 then starts backing down that's fine when its 30 degrees out but not when it's in the teens or lower. I've been reading about all the trouble with the 381-330-014 control board. i would like to change it the 381-330-026 Williamson tech said it would work but it needs modified, would not say how. from looking at the add it looks like it's got an extra green wire on it. i believe it's a ground wire. any way if anyone has switch to this control board 381-330-026 and you think it's good upgrade, please let me know also is the extra green wire a ground. made it through the cold weather the hard way looking to get a permanent fix. PLEASE HELP


  • dcpace78
    dcpace78 Member Posts: 3
    update on my gwa 105 series 2 boiler, i replaced the control board 381-330-014 with board #381-330-026. Williamson tech said it would work but it needed to be modified. but would say how, come to find out it you just need to run a ground wire. the new wire harness that connects to the temp censor will have the 4th wire (green) just wire it to the on\off switch ( white wire) on the side of the furnace. what's nice about the new control board is it has a Didital read out of the temp. its been running for 7 days now without a problem. temp range is 20 digress if you set it on 180 it will run between 160 up to 180