Ducted Systems Technical Services: Service Tips Letter
Letter:
ST-013-22
Date:
October 4, 2022 Effective: October 4, 2022
To:
S1 HVAC Branch and Distributor Principal, Sales Manager, Service Manager, Parts
Manager, Warranty Manager, Training Manager, Delegated Administrator.
Ducted Systems Technical Services, DS Parts/S1, ES Americas, ADTI Channel, Account
Representatives, Marketing, Sales, Warranty teams.
Subject:
Furnace Safety Control Devices with diagnostics and inspection
recommendations particularly for High-Temperature Limit and Flame Sensing
Controls
Product/s:
33” non-condensing furnace models GG8S, GGLS, RGF1L, RGF2L, TG8S, TGLS, TM8E,
TM8T, TM8V, TM8X, TM8Y, TMLE, TMLT, TMLV, TMLX, YG8S
Summary:
The following information is provided to explain safety controls, various fault
diagnostics, troubleshooting, and fault resolution for High-Temperature Limit
and Flame Sensing Safety Controls
Dear valued customer:
Johnson Controls takes product safety seriously. We provide safe and reliable products, designed, and
manufactured to applicable quality and safety standards.
As an effort to improve consistency in diagnosing and resolving failures or faults related to Safety
Controls and
specifically
to the high-temperature limit controls as well as the flame-proving sensor
controls, the following troubleshooting guide is being promoted for future use and reference.
Note: Whenever working on HVAC equipment, ensure that all power is turned off to the unit, use
appropriate personal protective equipment, i.e., gloves and protective goggles. Use required electrical
protection equipment and tools suited for electrical operation purposes.
Never bypass any safety control to allow furnace operation. To do so will
allow furnace to operate under potentially hazardous conditions.
Do not touch or adjust any safety devices inside the indoor or outdoor
units. All safety features, disengagement, and interlocks must be in
place and functioning correctly for proper equipment performance
Do not try to repair controls. Replace defective controls with UPG
Source 1 Parts
