Thread: Brivis Buffalo 85 EMS OH/F & OH/S errors

Hello everyone,

I have recently purchased a house with a Brivis Buffalo 85 EMS gas ducted heating unit. Unfortunately I have no idea on how old the unit is as there was no documentation or instructions left when I moved in. Now that winter has arrived I have powered the unit on and I have been having some intermittent issues which I am hoping some of you could assist me with.

The issues I am having are as follows;

1. Poor airflow from all ducts
2. Intermittent OH/F & OH/S errors on the control board

This morning I awoke to a cold house and no air flowing from the ducts. I checked the unit and the fan was running however the burners and pilot light were off. The control board was showing an OH/F (overheat fan?) error. I reset the unit and the pilot light kicked in and lit the burners, the fan started and I went back inside. After a few minutes I again checked the ducts and again there was nothing coming out of them. Upon returning to the unit, the burners were out, fan was running and the OH/S error was showing on the control board.

I'm trying to determine what is the likely cause of these errors? I can get to and replace the pilot burner easily if needed but I'm not sure if this will fix the problem. Having done some reading I think the flame rollout sensor might need replacing but I have no idea where to find this on my unit.

Attached are photos of my unit. The control board is currently showing everything as green however the OH/F & OH/S errors are intermittent.

Any help would be appreciated. Thanks.


Brivis Buffalo 85 EMS


Control Board


Wiring Diagram


Pilot Burner

If it's shutting down due to o/h issues, try checking your return air filter behind the r/a grille, if blocked with dust, will cause low airflow and will overheat unit, causing it to shutdown. Also if possible check all ductwork for any damage. p.s. this model was subject to a recall by Brivis back in about 2000, which I was involved, ring Brivis to see if yours had the update. It was free at the time but they will charge you to do it now.

Brivis Buffalo 85 EMS


Control Board


Wiring Diagram


Pilot Burner[/QUOTE]