Honeywell RM7800 Fault Codes

Update 8.4.2013 Click here to see a video on how to use the RM7800 Fault codes.

Fault codes are used on the Honeywell RM7800 series of boiler burner flame safeguard controls. These codes help the service technician identify problems that occur with the relay or the components that are wired to the relay.

These fault codes are sent to the S7800 display as so known as the KDM (keyboard display module) that can be mounted on the main RM7800 relay or remotely. The S7800 display will show operation and fault information along with other features

Over the years Stromquist and Company has been selling Honeywell controls and explaining these numeric fault codes to various clients. As luck would have it the other day I received a phone call from a client asking about a fault code that was showing up on his S7800 display. I searched the fault code references I had from Honeywell and could not locate the fault code the client was reading off the display to me. His fault code was 33Z. I have, in all my time working with clients, never saw or heard of a fault code ending with a letter value.

After several telephone calls to find an answer/solution to this problem I finally got an answer. It seems I forgot to ask one small detail about the client’s system.

When working with a RM7800 system and you get a bazaar fault code ask the client this question “Is there an S7830 Expanded Annunciator installed”. If there is a S7830 installed you need to look at the expanded fault code lists for the S7830 and there you will find the fault code number and in some cases this fault code number is followed by a letter giving you the proper diagnostic information.

I don’t know about you but this “ole dog” learned a new trick hopefully you can add this one to your bag of tricks.

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Over 35 years in the controls industry. Mr. Jones, Mr, Jones, Mr. Jones has a good thing going on... and lovin' it. Avid photographer, motorcyclist, and antique motorcycle restorer.

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  1. BoilerBoy says

    Great info…I have run into problems with the Honeywell fault codes at times (I am new to boiler tech work) and this explains alot

  2. Bob Duval says

    Hi guys. I have a Honeywell. 7800 burner control. Every thing works I even see a piolit flame. But it keeps locking out on 28. I changed all parts with another unit and all controls work I changed out the cath rod too but no luck still locks out. Any help would be nice

  3. Gary Bastajian says

    I have the Honeywell REM500R 1001. Trying to do the wifi set up. When I touch connect I get error code 38. What am I doing wrong?

  4. Bill says

    This is the meaning of the error code 38…ERROR CODE 38 MAKE SURE CONNECTED LIGHT…IS FLASHING and you are 2 plus feet AWAY from EIM or wireless adaptor

  5. Boiler Bob says

    I have a 7800 control w/display, it is indicating on the display “Trying to connect” it locks out the control display. What is the control trying to connect to?

  6. Kelton says

    Having trouble with Fault code 18 appearing within 1-2 seconds of RM receiving power. Have checked all the recommended areas in Keyboard display manual, and have replaced RM. Still getting fault code, but only when RM first starts up after being off for a while. When RM is reset code does not appear and RM operates properly. Any suggestions?


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