Reznor unit hetater issu(s)

[blenderbender]

I hung a Reznor FE-200 (200,000 btu) unit heater in an ag building recently. It's supplied by NG and supposedly worked when uninstalled previously before I got it. It sat around for a couple years before I got around to hanging it. Fan motor was slightly stuck, but easily returned to function properly. When I first tried to light it, the ignition spark is steady and clean, but pilot would not ignite. I then dropped the ignition/pilot assembly out from the bottom and then it lit no problem. But when I reinstall the pilot will not light. I manually lit pilot with a small butane torch and then everything happens as it should..... burners light, blower comes on when it gets up to heat. When the thermostat is satisfied and everything shuts down though, the pilot will not re-light when thermostat calls for heat again. The only tiny (in my mind) out of the ordinary thing that I've noticed is that when I manually light the pilot with torch, there is a slight gas leak at the fitting on the pilot line to the pilot as it ignites also. I tried to tighten it but it was to no avail, the gas is still leaking slightly at that fitting. The pilot, when lit, appears strong, and to my eyes, substantial enough. But for whatever reason it does not want to light on it's own when up in the burner box...... thanks in advance for any ideas!

 

[fitter30]

2014 rez was bought out to nortec need the serial to see what ignition parts ur heater has. Standing pilot ? Thermocouple? When u pulled the pilot assembly and tubing did u look in the pilot and blow it out. Could have a spider web in it. Could cut the 1/4" ferrel off the pilot tube and replace it for the pilot leak. Thermocouple only put out 35 mv, unscrew from gas valve clean the end with sand cloth reinstall. Using a torch is so much hotter than a pilot flame makes easy lighting but is very hard on the thermocouple if it gets to hot.

 

[blenderbender]

This appears to be the ignition/pilot module that is on my pre-2014 Reznor. I need to remove grille over fan in order to clearly see serial #. I did remove the pilot tube but there doesn't appear to be a ferrule, the end of the tube seems to be attached to what appears to be cylinder about the size of a .22 long rifle shell that has 2 tiny orifices on the end. I cleaned everything the best I could with tiny wire brushes before doing anything. I don't think I overheated the thermocouple, but what do I know. The tiny torch I used lit the pilot immediately. I can't fathom why it lights easily when dropped out side, but refuses to light installed.

 

[gmcgeo]

when you see it spark, is it sparking across the pilot or maybe elsewhere? ground issue?

if the leak is bad enough it may not lite right away, however later it may have a delayed ignition and have a small boom when it lights

 

[blenderbender]

It mostly arcs across to the thermocouple. It occasionally jumps to the pilot hood, and sometimes between both at the same time. But in general it's almost always to the thermocouple whether the unit is installed or just hanging loose underneath when it almost always light immediately. I haven't noticed what I would describe as any small boom when it lights.

 

[gmcgeo]

it should be hitting the hood. sometimes in the past i have adjusted the sparker to spark at the hood

 

[blenderbender]

hmmm... wondering how I might make that adjustment. Did you bend something towards the hood?

 

[fitter30]

That list shows nat gas pilot assembly 110853

 

[blenderbender]

I'm not sure what you mean by that.

 

[gmcgeo]

if you can lite it with a flame at it then your sparker is weak or porcelain is cracked at the sparker

 

[gmcgeo]

That list shows nat gas pilot assembly 110853

I'm not sure what you mean by that.

I think he is saying you need to replace the pilot assy.

 

[blenderbender]

if you can lite it with a flame at it then your sparker is weak or porcelain is cracked at the sparker

But it lights just fine when dropped out of the burner box. That's what I don't get.

 

[gmcgeo]

again, ground issue. when mounted its grounding elsewhere. replace the pilot assy

when the porcelain cracks on the sparker it can do that

 

[blenderbender]

Thanks.... DONE!

 

[fitter30]

Two other things to look at the flue is there at least 12" piece before ell offthe heater. The other where the heat exchanger sections come together at the bottom from the back and front look for a crack there easy to see. Here's a manual if u don't have one.

https://www.google.com/url?q=https://www.questargas.com/ForEmployees/qgcOperationsTraining/Furnaces/Reznor_FE_BE_Gas_Fired_Power-Vented_Unit_Heater.pdf&sa=U&ved=2ahUKEwjty7jHoZ71AhUvk4kEHTDLAScQFnoECAsQAg&usg=AOvVaw20HXHowEmCE9xFP35E3pY6

 

[blenderbender]

No, it 45's right off the flue into a straight run out thru the wall. Tomorrow I will check for the cracks you mention. And thanks for the manual!

 

[blenderbender]

Made some headway but still having other issues. Replaced the pilot ignition assembly and heater fired immediately, so that problem seems to have been sorted out. But now, with heater running, the gas valve keeps clicking every few seconds (wasn't doing that before or at least not as frequently as it is now. The fan continues to short cycle until the building warms up, which is what it was doing before. The burners stay lit the whole time.... well until thermostat is satisfied which isn't going to be for a while. It was 28 degrees in there when I replaced the pilot assembly. I'm gonna let it run and warm up and check on it later.

 

[blenderbender]

Made some headway but still having other issues. Replaced the pilot ignition assembly and heater fired immediately, so that problem seems to have been sorted out. But now, with heater running, the gas valve keeps clicking every few seconds (wasn't doing that before or at least not as frequently as it is now. The fan continues to short cycle until the building warms up, which is what it was doing before. The burners stay lit the whole time.... well until thermostat is satisfied which isn't going to be for a while. It was 28 degrees in there when I replaced the pilot assembly. I'm gonna let it run and warm up and check on it later.

After over an hour the valve clicking seems to have stopped. The fan is still short cycling but the warmer it gets in the building the longer the run cycles get. The temp is hovering near 50 deg. and I've shut it down for today.

 

[PoorUB]

The fan short cycling is because the fan runs on a snap disc thermostat. As the burner runs the limit warms up and turns on the fan. The fan starts and if if is fairly cold in the space the fan is blowing cold air over the heat exchanger and the snap disc opens again, shutting off the fan. My bet is if it was 60-70 degrees in the shop the fan will run constantly. Don't worry about it.

As for the gas valve perhaps the flame sensor is not getting a good flame over it all the time, perhaps worse with the fan running. Turn up the pilot adjustment a bit and it may stop. There will be a small cap or screw near where the pilot gas line comes out of the gas valve. Be careful and do not turn up the main gas pressure adjustment!!

 

[blenderbender]

Thanks!!! I'll try adjusting the pilot up tomorrow.

 

[blenderbender]

I fired heater up this morning.... no more gas valve clicking .... taking that as a good sign though unsure why it went away. At this point though I'm feeling as if problem(s) solved. Thanks everyone for chiming in.... couldn't have done it without you!