Low Water Cut-Off Electrode Assemblies – ITT McDonnell & Miller’s Series PS-801-U, PS-802-U, PS-851-U


August 9, 1999

Series PS-800-U Low Water Cut-Off Electrode Assemblies

We have recently discovered that McDonnell & Miller’s Series PS-801-U, PS-802-U, and PS-851-U, “U” type probe control electrode assemblies are defective and may fail in an unsafe manner. Consequently, we are recalling all affected “U” style electrode assemblies.

On some electrode assemblies, radial tears have developed in the Teflon probe coating. See graphic below. If enough conductive sediment accumulates between the tear and the barrel area of the electrode, an electrical short may develop. This problem can affect the functionality of the low water cut-off causing loss of low water protection, which could lead to a boiler dry fire.


ReCaa 241

“U” style Electrode Assembly


This applies only to the following “U” version (long barrel) electrode assemblies that were built between April ’97 and March ’99:
153916 PS-802-U-24 153876 PS-801-U-120
153887 PS-851-U-120 153884 PS-851-M-U-120
354141 PA-800-U (replacement electrode assembly)


Date codes of affected controls:

ReCaa 242


Note! This bulletin does not apply to standard versions of the PS-801, PS-802, PS-851 and PS-852. It applies only to “U” style electrode assemblies built between April ’97 and March ’99.

We recommend immediate replacement of affected electrode assemblies. (Electrode assemblies will be exchanged at no charge).

Boiler Manufacturers or Distributors should return all stocks of affected products (the entire probe control) to McDonnell & Miller, freight prepaid. (The freight charge will be credited back to you.) We will return the same type units with a corrected electrode. Please call your customer service representative here in Chicago for an RGA, and to schedule shipment of replacement units. We will make available to you additional stocks of replacement electrodes for your customers, based on our records of your sales of these products.

Installers or Owners of a system that uses an affected control should replace the electrode assemblies immediately, regardless of whether tears have appeared. Contact your local source of the boiler or the control for a replacement electrode assembly.

Reasonable costs for field labor associated with the electrode assembly replacement will be reimbursed. In order to be reimbursed, we must have received the replaced electrode assembly. For additional details, call Steve Mueller, our Customer Service Manager, at 773 267-1600.