Is my Mr. Heater running right?

[SteelHorseHD]

Hey guys,
I recently purchased a Mr. Heater 75k unit for my 36x45 garage. It was a nat. gas model but I converted it to propane. When it runs it barely puts off any heat. I can put my face directly in front of the heater while its running without getting too hot. Not only that, but from the few hours I've had it running its sucked down about 20 gallons of propane. So my question is: what is wrong with my heater? Is this normal? Or should I take it back? Thanks in advance!

 

[dave67fd]

Did "you" do the conversion or someone else? Was manifold pressure adjusted or checked? Im not specifically familiar with the conversion kit but i know the NG and LP units have quite different manifold pressures.

I would confirm gas fllow and gas pressure as well as a possible leak outside seeing as you didn't mention it.

You should at least confirm the LED on the control board is flashing properly for it's function. These are in your OM. It should fast flash for normal operation and calling for heat. You could also have a restriction on the line or burners.

Do a test to see how long it takes to heat the area from one temp to the other.
You could call your gas guy or provider to come check it out.

 

[rickairmedic]

When you converted it did you have the gas valve " properly adjusted " after it was converted . Also were the burner orfices changed out when the gas valve was redone .

Rick

 

[SteelHorseHD]

Yes I installed the conversion kit. Switched out the offices and the pressure regulator screw and spring. However, I didn't have the pressure checked. The guy from the gas company told me usually he just adjusts the screw until it's nice and blue. I have tried to adjust the pressure both ways and it doesn't change the heat output, just makes the flame bigger and with more yellow. My little 40k btu salamander will heat the garage 10x faster than the mr heater. Today it was 50 degrees outside. I set the thermostat on 65 and it took a good 1.5 of continuous running to raise the inside temp 7 degrees ( I figured when I got back from town it would be nice and toasty) I am going to call mr heater in the morning and see if they have a solution but I can tell you that it isn't producing 75k btu. I would be bending the truth if I said it was putting off 10k. I appreciate your input! I hope it's something easy like the manifold pressure or me just being a dummy and not installing the conversion kit the right way.

 

[rickairmedic]

Steelhorse I usually use a manometer when I change a furnace over from NG to propane . You can get a cheap water based one to set it properly. You should be around 11-13 inches of water column on a propane fired furnace .


Rick

 

[SteelHorseHD]

Ok that was my next step. I called mr heater and the guy wasn't helpful at all. Now, I've gotta track down a manometer! Thanks for your help!

 

[rickairmedic]

Look in your yellow pages or google for a local HVAC wholesale supply house " you may have a Johnstone supply " up there .

Rick

 

[porcupine73]

What's your supply between your propane and the heater? I mean is the line size large enough and is there enough pressure upstream of the heater's pressure regulator? Just throwing out some ideas.

I have that same heater, but left as NG. I have been having some trouble with one of the flame impingement sensors, even after I replaced it. It seems to happen only on windy days though, I think that makes it trip.

 

[A_Pmech]

No need to buy a manometer, you can make one in 60 seconds with a length of 1/4" vinyl tubing available from any hardware store and a yardstick, broom handle, 2x4, etc to tape the tubing to. Use a ruler to measure the differential:

 

[SteelHorseHD]

Thanks guys. I bought the 1/4 inch tubing yesterday and I am going to put it together tonight. My only question is: how do i connect it to the regulator? Do I need to buy a ****** of some sort with the same threads as the screw that is already on the regulator or just push it in the hole as much as possible?

 

[A_Pmech]

The White Rodgers gas controls on my Beacon Morris heaters have bosses which are designed to accept 5/16" tubing over them. I've seen some that use a 1/8" pipe thread for test ports.

You must have a good seal which prevents gas from leaking by the fitting. The heater must be running to adjust the manifold pressure pressure, presenting a fire hazard in the case of leaking gas. The pressure is low enough that any leaks between the gas control and the manifold will show an incorrect manifold pressure.

 

[SteelHorseHD]

Okay, I made my Manometer and checked my inlet pressure. It was right at about 10.5" and the book says 10 was the minimum. I checked the manifold pressure and it was at about 4 so I cranked it up until it reached 9" which was the highest I could get because the screw wouldn't turn anymore. I noticed a huge difference in the heat output right away but I also noticed that the flame wasn't all the way blue anymore and it was curving around the first bend in the heat exchanger. After a few minutes of operation I noticed that the heat exchanger was turning red (I was told that wasn't good) and I can only imagine how much propane the thing is sucking down!!
Any suggestions? You guys have been very helpful so far, thanks a bunch!

 

[matt60j]

I just fired up the same unit in my barn a few days ago. Did the conversion to lp and set it at 10 inches(11 full turns) when the cap was flush with the top of the valve. I have 1/2" copper running to barn then about 60' of 3/4" black pipe. Shop is 36'x40' took about 8-10 minutes to go from 50 degrees to 60. No issues. Good luck! -MATT

 

[brewchief]

Okay, I made my Manometer and checked my inlet pressure. It was right at about 10.5" and the book says 10 was the minimum. I checked the manifold pressure and it was at about 4 so I cranked it up until it reached 9" which was the highest I could get because the screw wouldn't turn anymore. I noticed a huge difference in the heat output right away but I also noticed that the flame wasn't all the way blue anymore and it was curving around the first bend in the heat exchanger. After a few minutes of operation I noticed that the heat exchanger was turning red (I was told that wasn't good) and I can only imagine how much propane the thing is sucking down!!
Any suggestions? You guys have been very helpful so far, thanks a bunch!

You do have the correct orifices in it right? The propane ones should be noticeably smaller.

 

[SteelHorseHD]

You do have the correct orifices in it right? The propane ones should be noticeably smaller.

Yes, I replaced the orfices. I believe they were .046 but I can't remember. I think I'm just going to have someone come out and take a look at it. What a headache!! The way that it is set up right now really puts off a lot of heat but I just don't think that it is set up the right way.

 

[SteelHorseHD]

What's your supply between your propane and the heater? I mean is the line size large enough and is there enough pressure upstream of the heater's pressure regulator? Just throwing out some ideas.

I have that same heater, but left as NG. I have been having some trouble with one of the flame impingement sensors, even after I replaced it. It seems to happen only on windy days though, I think that makes it trip.

It is 3/8 copper line to the regulator outside of the building and then about 10 ft of 1/2 black pipe running to the heater.

 

[matt60j]

how long is that copper run?

 

[SteelHorseHD]

how long is that copper run?

The copper run is about 30 ft.

 

[dave67fd]

That could be a problem. I believe at that length and 75k btu's you should be at 1/2" min. from regulator to heater.

 

[porcupine73]

Just double checking.....when you checked the inlet pressure with the manometer, was that with the heater operating?

 

[SteelHorseHD]

That could be a problem. I believe at that length and 75k btu's you should be at 1/2" min. from regulator to heater.

Okay thanks. I am going to have an HVAC guy come out soon and check it out before the weather gets too cold. I'll have him check that.

Just double checking.....when you checked the inlet pressure with the manometer, was that with the heater operating?

10.4" was the minimum pressure and the manometer said it was at about 10. I have thought about adjusting the regulator on the tank to increase the pressure a little bit.

 

[porcupine73]

Ok, but was the heater running (drawing gas, flame on) when you checked the pressure with the mannometer?

 

[SteelHorseHD]

Ok, but was the heater running (drawing gas, flame on) when you checked the pressure with the mannometer?

yes, I didnt really notice much of a difference when the heater kicked on. The manual says the maximum is 13" for the inlet pressure so I could probably turn it up a little and see if that helps. I checked both the inlet and outlet pressures with the heater running.

 

[porcupine73]

Ok thanks, was just wondering, to make sure the inlet pressure was sufficient when the gas was actually being drawn.

 

[A_Pmech]

What color is the regulator on the propane tank?

Is there another regulator at the building where the copper tubing transitions to iron pipe?

 

[SteelHorseHD]

What color is the regulator on the propane tank?



Is there another regulator at the building where the copper tubing transitions to iron pipe?

I believe the one on the tank is green.

The copper line comes out of the regulator on the tank and runs 30ft to a regulator on the outside of the building (green as well) and then 10ft of black pipe out of that to the heater.

 

[A_Pmech]

I believe the one on the tank is green.

The copper line comes out of the regulator on the tank and runs 30ft to a regulator on the outside of the building (green as well) and then 10ft of black pipe out of that to the heater.

Sounds like you have a two-stage system. The first stage tank regulator reduces the tank pressure to 10 PSI. Then, the second stage regulator at the building reduces the pressure to 11" to 14" of water. If your building supply pressure is low, you want to adjust the second stage regulator at the building, NOT the first stage regulator on the tank.

3/8" copper tube is more than sufficient to supply the second stage regulator with sufficient gas for your heater per Reg-O's "LP Gas Serviceman's Manual" first stage piping table.

At this point, if you're unsure how to proceed I recommend you have your gas company come in and check and adjust the heater for you. The service is usually free.

 

[SteelHorseHD]

Sounds like you have a two-stage system. The first stage tank regulator reduces the tank pressure to 10 PSI. Then, the second stage regulator at the building reduces the pressure to 11" to 14" of water. If your building supply pressure is low, you want to adjust the second stage regulator at the building, NOT the first stage regulator on the tank.

3/8" copper tube is more than sufficient to supply the second stage regulator with sufficient gas for your heater per Reg-O's "LP Gas Serviceman's Manual" first stage piping table.

At this point, if you're unsure how to proceed I recommend you have your gas company come in and check and adjust the heater for you. The service is usually free.

Okay sounds like a plan. I really appreciate your help with this!!!

 

[SteelHorseHD]

Update: A friend of mine finally had time to come over and look at the heater. He checked the inlet and outlet pressures with his digital manometer and adjusted them accordingly. The heater seems to be running pretty good after that. I am still going to add some more insulation up in the attic because there are a few spots where I was getting low on the cellulose so I couldnt put as much up there. The other night I had the thermostat set at 68 and the heater was kicking on for 4 min and off for 20-25. (the outside temp was only around 45 though) I installed 3 ceiling fans the other night but havent really had a chance to spend a lot of time out there to see how much they will help. We are going to have a few cold days coming up so hopefully the heater won't have any problems keeping the garage at a toasty 68 while me and my buddys are out there drinkin a few cold ones. I love how quiet it is though, you can barely hear it running!

 

[Huckster59]

How do you adjust to get rid of yellow flames

 

[Huckster59]

I have yellow flames on top burner. Mr heater 80000. Propane. Put kit in. Have a yellow flame and popping limit switch I’m guessing from yellow flame close to it

 

[PoorUB]

I have yellow flames on top burner. Mr heater 80000. Propane. Put kit in. Have a yellow flame and popping limit switch I’m guessing from yellow flame close to it

Read the thread, make certain the gas pressure is correct while the heater is running.

 

[Huckster59]

Yes I seen that. I guess I need to get a meter. Thanks