Jump to content

Recommended Posts

I bought an old propane Knipco on a sale. Was trying to get it running yesterday.

I tore it down cleaned the pilot light and nozzle and found the thermocouple  is good.

I hooked it to a 20# cylinder and lit the pilot light. That works as it should.

I plugged it in, the fan started, so I moved the switch that is moved when the fan is working and it fired right up.

I then put the lid on it and it quit.

If I get it working, but leave the top forward about 4 inches, it will work and very well.

But when I move the cover back to put the screws in it, it quits.

Once in awhile, it will try and start.

The only safety on this is the fan switch and that is working perfectly.

The only thing I can think of is a lack of propane from the small 20 lb tank.

Anybody messed with these and had these problems.

Link to post
Share on other sites

Had the same problem with a kerosene fired one. Has something to do with air pressure. I think the wrong pressure distorts the flame just enough to trick the eye. Just an aggravating problem with no good solution.

Are you sure there's not a regulator for the propane? When you bolt down the cover you increase the air pressure.

Link to post
Share on other sites

Never worked on the lp version. The problem is common on the kerosene version. The extra air pressure with the hood in place flattens the fuel cone in the combustion chamber moving it away from ignition source. First thing to look for is bent tin work or any obstruction to air flow around outside of combustion chamber. Second is fuel delivery pressure. As that will affect shape of cone as well. You've already cleaned the nozzles so that just leaves moving cone and ignition source closer together. I'm still trying to wrap my head around a pilot light in a forced induction burner. Most controls have a screw to adjust pilot. Perhaps you can turn it up alittle.

Link to post
Share on other sites

Unlike a kerosene one, there is no adjustment for the air.

The air adjustment on Kerosene models regulates the amount of fuel delivered thru the nozzle.

Mine does have a pilot light and there is an adjustment on the gas valve. It is set at max and only works in that position.

I agree this is either to much air or not enough fuel.

There was no regulator on the hose when I got it. It was open.

I think I will tear the gas valve apart to see if a spider, or something, was in the hose and now blocking the LP flow.

 

Link to post
Share on other sites
On 11/8/2020 at 8:56 AM, Diesel Doctor said:

The only thing I can think of is a lack of propane from the small 20 lb tank.

I doubt that's the problem, I have a 325,000 btu propane torpedo heater and it runs fine on a 20 pounder. Will run it perfectly until the frost line on the tank has moved down to the last couple inches of the tank.  She really heats though. Mine has a thermostat with an electronic spark ignitor, there is no pilot, so I'm not sure how that stuff works

Link to post
Share on other sites

does it have some sort of a low oxygen sensor?? My  heater I use for ice fishing has one, not sure how it actually works, but it will shut it off if it doesn't think there's enough oxygen around.

Link to post
Share on other sites

I have a LB white LP knipco that's about 4 years old.  Sometimes a 20# works, sometimes it doesn't.  A 30# works more often then a 20# but still not always.  A 100# always works.  I think the smaller tanks depend on the condition of the valve.

Link to post
Share on other sites
23 hours ago, Diesel Doctor said:

Unlike a kerosene one, there is no adjustment for the air.

The air adjustment on Kerosene models regulates the amount of fuel delivered thru the nozzle.

Mine does have a pilot light and there is an adjustment on the gas valve. It is set at max and only works in that position.

I agree this is either to much air or not enough fuel.

There was no regulator on the hose when I got it. It was open.

I think I will tear the gas valve apart to see if a spider, or something, was in the hose and now blocking the LP flow.

 

Rather than tear the gas valve apart, maybe disconnect the hose and check for bugs. Doubt that they would get into the valve,  most have a screen on the inlet. 

If it had no regulator, did you install one? Are you certain that it is the correct outlet pressure? The valve probably lists a max inlet pressure. If you don't have a regulator, you may be feeding it too much pressure. 

Link to post
Share on other sites

A heater should have 11” w.c. Sitting at its front door to run. Too much and the solenoid valve. Won’t open, too little it won’t light. 
sometimes the nut that screws the regulator to the tank has an orifice limiting the gas flow Mounts, different colors stand for different btu ratings 

Link to post
Share on other sites
21 minutes ago, zleinenbach said:

A heater should have 11” w.c. Sitting at its front door to run. Too much and the solenoid valve. Won’t open, too little it won’t light. 
sometimes the nut that screws the regulator to the tank has an orifice limiting the gas flow Mounts, different colors stand for different btu ratings 

I have two convection heaters that run at ten psi. So it depends on the valve. He hasn't responded what he used for regulator yet.

Link to post
Share on other sites
  • 1 month later...
On 11/9/2020 at 8:31 PM, zleinenbach said:

A heater should have 11” w.c. Sitting at its front door to run. Too much and the solenoid valve. Won’t open, too little it won’t light. 
sometimes the nut that screws the regulator to the tank has an orifice limiting the gas flow Mounts, different colors stand for different btu ratings 

I had the gas valve apart and found nothing wrong.

I do have a low pressure regulator on the hose at the tank.

I have the low pressure tester and with the tank on, and the heater not running, after the regulator, the pressure is at 15 w.c..

Is that to high a pressure and causing the problem?

Link to post
Share on other sites

I have a Knipco propane heater that I think is probably the same as yours.  I used it for years, loved it for the shop as you couldn't smell it burning at all.  Then, it got to stinking very badly, putrid propane smell while burning, you could tell it wasn't burning right.  I've had it apart numerous times, cleaned everything, varied every setting there was, adjust regulators, different regulators, different bottles etc, never solved it.  Sure would like to get it to work.

Link to post
Share on other sites
1 hour ago, Diesel Doctor said:

I had the gas valve apart and found nothing wrong.

I do have a low pressure regulator on the hose at the tank.

I have the low pressure tester and with the tank on, and the heater not running, after the regulator, the pressure is at 15 w.c..

Is that to high a pressure and causing the problem?

I’ve seen it where the gas is too high and the solenoid won’t open against that pressure, but it’s usually pretty drastic... I’d think 15” wouldn’t be THAT big of a deal

Link to post
Share on other sites
7 hours ago, Delta Dirt said:

What type heater are ya'll referring to when you say Knipco??

 

DD

Anson,

That is an incredibly fortunate “problem” for you to have, not knowing what a Knipco/Herman-Nelson/torpedo heater/salamander is!!!

The air temperature is running about 4 degrees Fahrenheit here today and I am NOT LIKING IT!!!!

Where is GloBULL Warming when you need it?????

Link to post
Share on other sites

Don't worry----We get cold enuff!!!😰

That's the type heater I thought ya'll must be talking about.

Reason for interest is that one of my big freestanding fireplace type heaters will not light.  Appears to me that gas is not passing through the control valve with thermostat.  Heater must be 20 yrs old----- ever any problems  before with no change in gas supply.  Serviceman is looking for new control valve----but no luck so far.

Am thinking I need to take valve apart and clean.  You think of propane being clean-----but I have seen several instances of small passages to gum up or collect trash on tractor and truck applications.  Not unusual to find in line filters plugged.

Will keep watching to see what happens here-----thanks.

 

 DD

edit:  just shooting from the hip here-----but if you are getting any gas through the control valve;  you should be able to ignite it by using a hand held stove type lighter.  At least prove that some gas or no gas is coming through the valve.  

In my case-----we are getting no passage of gas through the valve.

From what has been described------the lighter and control valve appear to be a similar set up of each other.

And------I don't know how the carbon dioxide safety switch works???

Link to post
Share on other sites
10 hours ago, farmall57 said:

Found this pic online of one just like mine.

 

knipco.jpg

That is exactly what I have!

Link to post
Share on other sites
2 hours ago, Delta Dirt said:

Don't worry----We get cold enuff!!!😰

That's the type heater I thought ya'll must be talking about.

Reason for interest is that one of my big freestanding fireplace type heaters will not light.  Appears to me that gas is not passing through the control valve with thermostat.  Heater must be 20 yrs old----- ever any problems  before with no change in gas supply.  Serviceman is looking for new control valve----but no luck so far.

Am thinking I need to take valve apart and clean.  You think of propane being clean-----but I have seen several instances of small passages to gum up or collect trash on tractor and truck applications.  Not unusual to find in line filters plugged.

Will keep watching to see what happens here-----thanks.

 

 DD

edit:  just shooting from the hip here-----but if you are getting any gas through the control valve;  you should be able to ignite it by using a hand held stove type lighter.  At least prove that some gas or no gas is coming through the valve.  

In my case-----we are getting no passage of gas through the valve.

From what has been described------the lighter and control valve appear to be a similar set up of each other.

And------I don't know how the carbon dioxide safety switch works???

This is a heater before much safety crap.

If the pilot goes out, it shuts off the pilot gas due to the thermocouple. The fan will run but no gas will flow to the nozzle. 

If the fan don't run fast enough, the fan switch, which turns on by the air moving by it, will not allow the main propane to come on.

Yesterday I had the top cover on it and then covered 3/4 of the air inlet at the rear and it starts and runs fine.

It appears to be too much air or not enough propane.

But which is it?

Link to post
Share on other sites

It's the gas cone and pilot light not meeting. Moving gas nozzle back or pilot forward or closer to center should solve problem. 1/8" makes big difference. Probably not readily adjustable but things can be shimmed or cutoff. Gas pressure at this point has more to do with temp at end of combustion chamber.

Still having a hard time with pilot in forced air stream. Is there any kind of baffle or deflector in there that could be burnt or bent slightly? Can we get a picture of the burner and pilot assemblies?

Link to post
Share on other sites

I would think too much air.  If it was too much gas-------you should be able to smell the unburned gas or it would show up with the portable fighter's flamd.  (think of flooding an engine)

Can you partially block the air inlet with tape-----play with it until working proper??

At one time I was pretty good on setting the mixtures on L-P powered trucks and tractors.  Besides maximizing rpm------I smelled of the exhaust.  Checking them on a professional sniffer unit------I was always pretty close.  I would think the mixture on the heater is a similar function??

You are making me want to work on my heater------but I am just about past that point physically.

 

DD

Link to post
Share on other sites
On 11/9/2020 at 8:55 PM, snoshoe said:

I have two convection heaters that run at ten psi. So it depends on the valve. He hasn't responded what he used for regulator yet.

Ten PSI. ???   Ok I have never herd of that but then again I havent herd of everything .  
 

10” WC.    And 10 psi are two completely different things however. 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...