In a technical bulletin published by another burner manufacturer an explanation of the wiring colors for pre/post purge cad cell controls was given. That bulletin stated that the limit wire on the control was “commonly red” and the L1 power was “commonly black”. I feel it is IMPERATIVE that I correct that statement to avoid any possibility of mis-wiring and potential hazards that could result. Carlin introduced the first valve delay on (pre-purge)/valve delay off (post-purge) controls in 1995. Carlin was VERY careful to keep with the color-coding that had become industry standard for cad cell controls. The Carlin 60200-02 control utilizes the black wire for the limit circuit; this is in keeping with ALL cad cell control wiring prior to the 60200. The Carlin 60200-02 has a red wire with a white chaser for the L1 power.

When Honeywell introduced the 8184P valve delay on/valve delay off control they chose to break with the wiring color convention that has been established by Honeywell, followed by Carlin and is now industry standard. In the Honeywell 8184P and 7184P the red wire is for the limit circuit and the black wire is L1 power. To imply that this wiring is “common” is misleading. The industry standard that was in place was just the opposite of what is being termed “common” in that bulletin. This is a very important point for technicians to understand because of the potential problems that could result from mis-wiring any Carlin or Honeywell Pre/Post Purge Controls. Mis-wiring of the red and black leads on either of these controls could result in a situation where the burner will run to high limit and continue to cycle on high limit. This will result in the over heating of the building and if the limit should fail, far worse damage could result.

The following are wiring diagrams for the Carlin 60200-02 and the Honeywell 7184P controls. PLEASE distribute these to your technicians and make sure that they are familiar with the difference in the control wire color-coding. If you have any questions PLEASE do not hesitate to contact the Carlin Technical Hot Line at 800-989-2275