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.

Weird install of Weil McLain HE-ii

bikeveloce Member Posts: 1
Hello, I purchased a four plex with two Weil McLain HE-II boilers. The previous owner piped them in series, jumpered the thermostat circuits, and then setup an old mechanical thermostat connected to a relay transformer that turned on and off a switched outlet to power the boilers. When the thermostat called for heat, the relay would switch the outlet on, and the boilers would fire up because their power was restored. Also, the circulator power leads from the two boilers are wired together in a j-box and then to the circulator. And lastly, the switched outlet powering the boilers is not grounded. 

The boilers will not fire up. I figured out that one of them has a bad control box because it’s not providing power to the ignitor, so I simply bought new 1013-200 controllers for both and installed them today. This did not solve the issue. They both show two solid red lights and the green light is flashing - indicating the controller needs to be replaced according to the troubleshooting guide. However these are brand new controllers. 

Furthermore, when I unplug the power lead from the control board the BOILER TURNS ON AND FIRES UP. I figured out that the 120v bus in the control board is being backfed from the circulator circuit. So clearly, all of the sensors and safety circuits on the boiler are functioning, such as the pressure switch, limit, flame sensor, etc, since the boiler is running.

Does anyone know why the boilers will not initiate in the normal manner? Is it because they are not appropriately grounded? Is it because the circulator circuits are bridged between the two boilers without a relay? I have no idea how to resolve this issue. Does anyone have some insight?


  • Jamie Hall
    Jamie Hall Member Posts: 23,443
    Honestly, I'd start right back at square one. That wiring you describe is... um... unusual. Your best bet is going to be take it all apart, sit back for a bit, add some new controls where needed and probably some relays, and start all over again.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • pedmec
    pedmec Member Posts: 988
    You need an electrician first. Then purchase a tekmar 262 or equivalent boiler control to cycle the boilers on and off and to reset the supply temperatures to the loops. Depending on the piping arrangement this type of set up is used best but pics would help to sort out really what you need. How it is piped will help determine the best course of action.