propane smell from heil

[2weeks]

replaced an existing propane fired horizontal furnace in a crawl-space, 2 weeks-ago.I put in a heil 50k,90+ with a honeywell smart valve.Everything was o.k. until the homeowner called with a complaint about gas fumes.Went back to the job,into the crawl-space and noticed a raw gas smell only when the unit finished it's firing cycle.With the panel to the burner section off, I did notice that I could smell raw propane coming from the manifold,that is left once the gas valve shuts-off and the flames exstinguish.I took my lighter and lit this residual gas on the lower spud. This will burn for a few minutes before finally going out.I replaced the honeywell valve w/proper propane kit installed and set incoming pressure to 11"w.c. and manifold to 10"w.c. The unit fires-up and runs properly but still get that smell between cycles. Has anybody had this problem before? NOTE: all gas piping and fittings are absolutely leak free.

[Jultzya]

Can you light the gas on the manifold with the new valve too?

Is there a drip leg on the gas line?
Was there debris in the old valve?
Did you trace the wiring to make sure it was wired correctly from the factory?

I have on one unit found that the valve was wired wrong. It would spew pilot gas the whole time, once the unit was powered. I caught it at startup. It would run and everything, but I knew the unit had an extra 'click' when the power was applied to unit!

This is where it's important that you know your equipment like the back of your hand. This could have turned out to be a very bad situation if, the start up guy wasn't familiar with this unit.

[tinknocker service tech]

are the orficies the correct ones for that unit or is this unit able to be converted to propane. sone units must be ordered already set up for propane and can not be converted
have it looked at by a propane qualified tech.
propane is heavier than air and lays on the floor and since the odor is added to it and can disapate so you can no longer smell it. it can be very unsafe and dangerous
get someone to look at the unit as soon as possible
best addvise to give in my opinion is turn the gas off call someone that realy knows how to work on propane and be thankful nothing happened

[Jultzya]

Haven't seen ANY newer Heil units that can't be converted to LP gas. The burner orifices wouldn't have anything to due with the gas valve passing gas when it's supposed to be closed!

He needs to find out if the valve is power on the right pins.

[alaskan tinman]

(replaced an existing propane fired horizontal furnace in a crawl-space, 2 weeks-ago)

Better look into local codes : As far as here propane in crawl not legal.Propane is heavier than air and settles , becomes bomb potential.

[Jultzya]

Are you actually in Alaska?

I have never heard of this being against code. So, I'm curious as to your location.

[wormy]

not familiar with that brand furnace.
Is the manifold in a 'chamber' thats isolated from the furnace? The 90% furnaces I've delt with have the burner section closed off with a fresh air pipe coming to it from outside.
If you are opening this up and lighting residual gas at the manifold.. I think you are barking up the wrong tree.
Any gas leak there would have to be 'smelled' at the fresh air inlet pipe / combustion air inlet pipe. All furnaces have that residual gas you can light at the end of a cycle.

Where exactly did the customer smell the odor?
Did he go in the basement/crawlspace and smell it around the furnace? Did he smell it in the house?
Are you sure he's not smelling a dead mouse decomposing?

If you smelled the gas fumes at the furnace... then did you check the break away ferral fittings on each end of the pilot tubing while the furnace is operating?
Do you have an electronic leak detector (for combustible gases)?
You mentioned that the fittings don't leak... did you check the gas cut off valve? Is it an old one with the nut you can tighten on the oposite side of the valve handle?
Are you using soap and water to verify no leaks, or something like tru-blue or bird dog solution?

[2weeks]

Thanks for the reply guys. The furnace that I installed is set up to run with LP and does have the proper manifold orifices installed [#54's]with an LP orifice in the pilot burner.I did check all pipe connections with soap bubbles and also checked pipe and fittings for "sand-holes,from casting." I've been a top-notch service and installation tech. for almost 20yrs. now so, I wouldn't ignite a lighter in this situation if it wasn't absolutely safe.The burner section and manifold, on this unit, are not completely sealed as in some other units. The entire burner section with the pressure switch and inducer assembly are sealed from the outside of the unit by the panel cover.Like I mentioned earlier, the smell only accurs at the end of the heat cycle. I just thought that maybe someone might have come across this problem in their travels.Thanks again for your comments and any further information anyone might add.NOTE:ferrals are leak free, gas valve is wired properly and the gas pipe does have a proper drip leg.

[tinknocker service tech]

2weeks
sorry but your first post sounded diy
the second sounded more pro
i have come across this 2 times
first time the plumber and propane guy didnt get together to well and niether one installed the diaphram at the pool house i was do a start up 45,000 btu wall mount bolier with infloor radiant heat. smelled gas as soon as i walked in the door pressure was 90 lb. shut the gas off at tank and then blew my lid at the propane guy. thank god i didnt just hit the switch first. the propane co put in the diaphran and i replaced the gas valve and did the start up
second time the installes converted a lenox ghr26 to propane. they used pipe dope on the orfices and they realy doped them up. went there cause they said the flame didnt look right and they smelled gas when the unit shut down. the orfices had dope in them and not all the gas could get through after shut down the gas would weep out
i cleaned the manifold and blew it out and replaced the orfices and it was fine. i recomend calling hiel and get tech support to help you out or have them come out with you so next one you can resolve before hand