Gas Smell at start up

[Tommyzirk]

Hello I am a Facility manager and I have a building where one section of the building is serviced by a 10 ton Trane packaged gas and electric(Reliant). At start up of heat mode we get a whiff of natural gas that disappears quickly. I had the heat exchange smoke tested and found no leaks . The tech also changed the ignitor, but we still get the gas smell. Any ideas on my next move? TK

[Chris_Worthington]

Gas Meter Vent next to the outside air intake? Any Gas vents next to the outdoor air intake? Is a N.O Vent valve off a boiler near the outdoor air intake?, Light off fails on 1st attempt and exhaust gets sucked into the outside air intake?

[timebuilder]

Hello I am a Facility manager and I have a building where one section of the building is serviced by a 10 ton Trane packaged gas and electric(Reliant). At start up of heat mode we get a whiff of natural gas that disappears quickly. I had the heat exchange smoke tested and found no leaks . The tech also changed the ignitor, but we still get the gas smell. Any ideas on my next move? TK

I think you mean ReliaTel, the control board iteration.

Are you saying you smell this on the roof, or in the building?

[MicahWes]

I had a cinema having the problem Chris stated (ignitions were frequently failing and unburned fuel was getting exhausted from heat exchanger and getting pulled into the make air hood on the unit). It was very noticeable inside when the conditions outside were right.

[ACFIXR]

Hello I am a Facility manager and I have a building where one section of the building is serviced by a 10 ton Trane packaged gas and electric(Reliant). At start up of heat mode we get a whiff of natural gas that disappears quickly. I had the heat exchange smoke tested and found no leaks . The tech also changed the ignitor, but we still get the gas smell. Any ideas on my next move? TK

I have found pressure port caps on the "out" side of gas valves loose when checking this complaint. There is only a leak when there is a call for heat.

[bustedknuckles]

Also a loose union after the gas valve,. Made us look stupid, taking a week to find it.

[rscamaro]

I've seen similar problems with larger tonnage Trane RTU's. If the burner is not operating correctly it can mis-fire and a small amount of unburnt fuel will be leaving the exhaust ports and be pulled into the economiser housing and into the space. A few factors can be the cause of flame failure, all of which can be fairly easy to find with the right tools and the right technician. It all has to do with the amount of combustion air entering the chamber. Your tech will need a negative reading manometer if it is the system that I'm thinking of.

...Ron