SUBJECT:  Replacing Your WM97+® 155 and ECO 155™ Burner Gaskets
The WM97 155 and ECO 155 boilers manufactured before CP number 7004670, February 2014 were manufactured with a fiberglass burner gasket. The gasket glue seeped out of the gasket and electrically insulated the burner flame signal, so a weak flame signal would not allow the burner to run.  Some of these boilers would run for months, others failed soon after install. 
The symptom is that the burner would short cycle, running only for a few seconds and then dropping out. There was no lockout and the boiler would constantly recycle, therefore failing to produce heat. The solution is to replace the burner gasket with a new graphite gasket. The part number of the graphite gasket is 570-318-101 and may be ordered through any Weil-McLain distributor. To initiate the parts warranty, please contact our warranty group at 855-627-6003.
A temporary fix, such as changing the boiler model under “Boiler Settings” from a 155 to a 110, may allow the boiler to operate until the burner gasket is replaced. The minimum flame signal for the 155 is 150 and the minimum flame signal for the 110 is 50. However, it is important to replace the gasket as soon as possible.  The boiler must be reconfigured as a 155 boiler for proper operation once the gasket is replaced.
Before replacing the burner gasket, make sure gas and electricity are both turned off.
1. To replace the gasket, remove the heat exchanger top cover plate from the boiler, using a #10 metric wrench.

2. When the three metric nuts are removed from the cover plate, use a stubby #2 Phillips screwdriver to remove the plate screws and remove the burner cover plate. Remove the heat exchanger cover plate by tilting it up and out, then lifting the burner until the entire unit is free from the heat exchanger. 

3. Remove the fiberglass gasket from the underside of the burner lip. Clean the lip and burner mating surface with alcohol and a Scotch Brite pad to remove all the glue.  Clean the three points of the burner cover plate which hold the burner in place.3

4. Install the new graphite gasket and reassemble the burner and cover plate to the heat exchanger. 

Return boiler to proper operation and verify as per boiler manual start up procedure.

Important: At “Boiler Settings”, verify and/or return the boiler model from 110 to 155.