Raw Propane on Ignition

Alan (California Radiant) Forbes

Hey Everyone:

I service a new HTP Versa Hydro boiler in a rural area of the East Bay. Since it's outside city the city limit, they don't have natural gas service, only propane. I didn't do the install and it was set up properly, but there is a lingering problem. Everything is working fine, but there is the smell of raw propane on ignition. I checked all the connections and they are leak free. The smell of raw propane is there only on ignition and then goes away.

The local HTP rep. says to screw the throttle adjuster (fuel/air mix screw) all the way in and then back it out the same number of turns and that should fix the problem. My customers asks me how that should fix the problem and I can't give him an answer since it doesn't make sense to me either how that would stop a leak. When I called HTP tech. support, they didn't think that was a proper solution either and suggested a gas sniffer to find the source of the smell.

Has anyone had this same problem? Solutions?

icesailor

If you do gas, you need a sniffer. It might save your live someday.
That along with a Digital +/- pressure manometer for testing negative pressure valves.

I once wailed on a job to service a backflow. A place I hadn't ever been to. As soon as I walked in the door, I smelled either a dead animal, or Mercaptan,. It was LPG in the building. Or CO unburned exhaust. My CO detector said it wasn't. My Sniffer said that there was gas at extremely low conditions. The closer I got to a crawl space, the heavier it became. I stuck the sniffer probe over the wall and it went nuts, The entire crawl space was filled up with gas from a piece of CSST that was rubbing on a steel beam. The caretaker said it started 5 years before. Everyone said it was a dead animal. There was a light switch outside the crawl space access. Good thing I didn't try the light.

Get a sniffer. For your own safety and piece of mind.

Zman

What is the combustion analyzer saying?
High and low fire?
Certainly not normal.

Alan (California Radiant) Forbes

Hey Guys:

Manometer readings are good: ~9" WC on the supply side and a slight negative pressure (-.01 WC) on the manifold side.

Combustion readings: ~10 ppm CO, 9-1/2% CO2.

All the numbers are goods, no?

The smell of propane is there only during ignition.

Mark Eatherton

Alan, I had a similar experience with a Munchy many years ago running on natural gas. Found out that the gasket used between the gas valve and the air intake manifold had a cardboard gasket that had dried out and cracked and was leaking air and fuel on ignition. Once the blower ramped up, the odor went away, but in reality, it was still there, just being masked by the contaminated air being drawn into the combustion process. Look at all gasketing between gas valve and combustion chamber. You can use an approved detergent to fine tune your leak detection.

ME