Flame Controller Reset Regulations?

[JeremyM]

Had an interesting conversation with one of our burner manufacturer’s service engineers today regarding the use of reset mechanisms.

We were investigating the possibility of enabling a setting on a set of burners that would enable being able to reset their control units following a fault through a communications channel (Modbus in this case) rather than by a currently hard-wired circuit. He stated that the manufacturer had claimed that such a reset mechanism would violate regulations (somewhere) and that a remote reset like it was therefore prohibited. He went on to say that the setting documented in our literature didn’t even exist or was inaccessible. The burners and their managers are manufactured in Germany, but we install, commission, and integrate them into automated systems all over the place.

Am I wrong in thinking that, in literal and practical senses, anything beyond the unit’s HIM would constitute a remote reset, including the existing reset circuit already in-place? We are able to activate/deactivate heat and transmit setpoint over comms without issue. The burners alone also don’t ship with high-temp controllers, so we supply and integrate them in series with the safety circuit. They require a manual reset when tripped.

What makes the burner reset get this kind of attention?

Anyone else run into this topic before?

 

[NetNathan]

Usually, with burner systems, you have a MANUAL reset on the gas valve for initialization.
I have extended this to a momentary PB on the control panel for "Burner Gas Okay", which includes an e-stop for flame control to drop out the manual reset gas valve, but leave air on to purge the burners.
And of course you still have low/high gas pressure switches to "prove" before you can turn on gas and leave on.

 

[JeremyM]

All true, and we do such. In all cases, we defer gas train operation to the manager and its sequences.

Does the manual reset infer it must also be by wire, and wire alone?

A reset signal on its own doesn’t constitute a safety feature and its action is filtered outright by the burner; it already rejects resets held for too short or long of a fixed duration, or even a signal held prior to fault (as it should). In addition, too many resets within a rolling interval automatically forces a lockout condition under mandatory duration (15 minutes).

We condition the the code behind resets to be manual, including stubbed code that would serve the same purpose over comms.

 

[NetNathan]

Depending on the gas valve you have, the Reset may be a manual handle that must be "cycled" to energize the valve.

 

[JeremyM]

No such thing with these units. Just the keypad and a parallel reset circuit that serve the same role.

I’m bugged now about the manual reset. If we tie a reset button into a safety PLC that, by programmed logic, ‘ensures’ a manual reset by outputting to a force-guided relay servicing the burner’s reset circuit for only the duration of the physical press, does this count?

 

[JRW]

Jeremy
I’m with you. The reset doesn’t matter.

As long as the purge cycle starts back over and expires before another trial for ignition, it doesn’t matter what resets the burner system.

I’m assuming this is what your referring to

 

[James Mcquade]

i don't have my books and it's been several years, but there is an osha manual on boilers, gas fired ovens,... that require a manual reset after a fault and a system inspection has been preformed to verify system integrity. the rules may have changed since my last system install, but i think it is still there. i would have to look for a good while to find that book in the attic, i moved recently. if i am incorrect, someone please correct me.
james

 

[JeremyM]

Jeremy
I’m with you. The reset doesn’t matter.

As long as the purge cycle starts back over and expires before another trial for ignition, it doesn’t matter what resets the burner system.

I’m assuming this is what your referring to

Yes.

 

[NetNathan]

Jeremy
I’m with you. The reset doesn’t matter.

As long as the purge cycle starts back over and expires before another trial for ignition, it doesn’t matter what resets the burner system.

I’m assuming this is what your referring to

Yes, that is correct. I was only referring to turning the main gas ON to the furnace and its required safeties. That is what requires a manual reset.
Among other safeties for it.... is also over temp condition.