Mr heater issues. .

[joems-1]

Hi there everyone. New to the forum. Just built a 26’x32’x12’ shed recently and installed a mr heater 50,000 btu furnace in it. Horizontal flu pipe out the side of the building with a wind cap. Now that it’s starting to get windy im having trouble with the unit short cycling. Flame keeps going out and then relights and works for a short period and goes out again. No wind and it works great. Was told by the mr heater tech it is a bad pressure switch and replaced it but it still does it. If i bypass the pressure switch it will stay running. No codes present on the unit either.
Just curious if anyone has encountered this issue or knows what to possible do? Thank you

 

[whateg01]

There was at least 1 thread of this type of issue awhile back. I'm not sure what to tell you to search for though.

 

[ridgepatrol]

Changing out vent termination options (wind problems)​

Read through the above link.

I ended up adding some louvered end caps to the T-termination on the Mr. Heater vent kit. This allowed me to adjust how the wind was blowing into the T.

This eliminated almost all of the wind problems I was having.

Finally, I cleaned the flame sensor with some emery cloth, and I have not had a problem in the two years since.

Good luck with your install. It gets very windy on our side of the lake!



Here is the link to the end cap on Amazon, this is a black painted version, the two I have are natural stainless.

https://www.amazon.ca/piiyoosnn-Sta...ess+vent+end+caps&qid=1735819542&sr=8-11&th=1

 

[joems-1]

Changing out vent termination options (wind problems)​

Read through the above link.

I ended up adding some louvered end caps to the T-termination on the Mr. Heater vent kit. This allowed me to adjust how the wind was blowing into the T.

This eliminated almost all of the wind problems I was having.

Finally, I cleaned the flame sensor with some emery cloth, and I have not had a problem in the two years since.

Good luck with your install. It gets very windy on our side of the lake!


Here is the link to the end cap on Amazon, this is a black painted version, the two I have are natural stainless.

https://www.amazon.ca/piiyoosnn-Stainless-Hemispherical-Ventilation-3-inch（70mm）Black/dp/B0CCCWFLN4?dib=eyJ2IjoiMSJ9.tnC02wxsbBe29xl5ejcZGbrH6ihSfRDiT9uaKvY8cwZ6sOE9tss58Q3cqbYJK_nhgqt2nSfMKnJ-pMAC08BetZfN8T5_LdgHoovx3md9SKGie4RXxusTeSGvTKYj9Tfwu_OtSudjUhiy1PoA8IEMPOohfyMaQcg9u06N58uHs49qQAMBwurF5DYWRI2ciHIZUVQji7mfYrdxIwRrrUY15RFn0drTW_5VDYJqxr9hp3YARJ9ll09_XTKPqXZ7_4I43f0DSeH_2pS9Rk1ME6OkrHC8o9-YaIEkNNo1L-pe0mgSnD4IyFyZg0-g3nbyREN1VUVj2Pz8B-9yJ43hDetE-83FXRky9ka0irLmIPzM0L25kAdy5HoD7guk52ql92ezax51hoWPtED96pRj2t--nuVtdyqFE_ezM1LzL6onACygeG8z_ztooJWkcGQj7nSP.t89D0gpxdrqUnA7vEH2R9VG4gMYRLXcObpDp9gDf7OA&dib_tag=se&keywords=stainless+vent+end+caps&qid=1735819542&sr=8-11&th=1

Thank you so much!

 

[daws87]

I installed the Mr Heater Big Maxx 50k a few years ago and also vented horizontal just due to location and it was easy.

If the wind is just right I've noticed it short cycling as well. Doesn't happen often and right now I'm just ignoring it but might order that end cap and try it out.

My neighbor has the exact same setup as me (same unit, vented horizontal, same termination T) and doesn't have this problem but his vent is facing the south side of his property with a berm/woods blocking most of the wind.

Mine is venting N/NW so it gets the brunt of our cold MN winter winds.

 

[ridgepatrol]

This past week, mine started to act up again due to wind from the SE. It was not happening as much as before I installed the end caps, but the burner would not stay lit for more than a minute and then would relight.

I found a Reddit thread on this same issue.

https://www.reddit.com/r/HomeImprovement/comments/qptg0k
The suggested fix from the manufacturer was to rotate the pressure switch 180 degrees and reinstall.

This is an interesting fix, because when I installed my heater I flipped the heater so that the control board was on the right side, instead of the factory original left side. This allowed me a better path to route the exhaust.

I would not have thought that the orientation of the pressure switch would make a difference, but we shall see.

 

[cleveivy]

Wind can definitely mess with these heaters. I’d try rotating the pressure switch, it sounds odd, but it worked for me.

 

[joems-1]

Ridgepatrol

This past week, mine started to act up again due to wind from the SE. It was not happening as much as before I installed the end caps, but the burner would not stay lit for more than a minute and then would relight.

I found a Reddit thread on this same issue.

https://www.reddit.com/r/HomeImprovement/comments/qptg0k
The suggested fix from the manufacturer was to rotate the pressure switch 180 degrees and reinstall.

This is an interesting fix, because when I installed my heater I flipped the heater so that the control board was on the right side, instead of the factory original left side. This allowed me a better path to route the exhaust.

I would not have thought that the orientation of the pressure switch would make a difference, but we shall see.

I bought the T and the vented end caps just like the ones you have and installed them and it did not make a difference for my unit unfortunately. All worked well till a windy day against the flu side. I will try the pressure switch flip now and hopefully that helps.
I am still trying to understand what exactly is going on though as mine does not set any LED codes for the pressure switch. Is it simply just blowing the flames out?

 

[daws87]

Ridgepatrol

I bought the T and the vented end caps just like the ones you have and installed them and it did not make a difference for my unit unfortunately. All worked well till a windy day against the flu side. I will try the pressure switch flip now and hopefully that helps.
I am still trying to understand what exactly is going on though as mine does not set any LED codes for the pressure switch. Is it simply just blowing the flames out?

Everything I'm reading says LED codes aren't typically thrown for this.

While this is a very rare issue for me I'm still going to flip that switch this weekend as it looks to be an easy, straightforward fix.

 

[joems-1]

Just an update, flipping the pressure switch did nothing for me either. Another windy day and its short cycling. I did take the clear hose off and jumped the pressure switch and it worked great till i switched it back. I also put a carbon monoxide detector in the shed when i did this just to just make sure.