Furnace - low gas pressure?

[jakehabing]

I have installed a 80% furnace. It is converted to run on propane and the manufacturer suggect a minium of 8" WC for the maniflod pressure. I have been able to get it up to 7" WC. I have the inlet pressure at 13" WC which is the maximum the manufatured suggects. My question is will the lower manifold pressure cause any problems ?

Thanks for your Help.

[Brian_UK]

Not that we know a lot about burning gas on here but do you have the correct size injectors. And do you have 13" with the burner running?

[jakehabing]

Brian,

Thanks for your reply. Yes, I do have the right size of injectors. No, when the burner is running the 13" goes down to the 7" as well. I know this means that my gas line is too small. This is a installation in an older building, new gas line is a last option. My question is will the lower gas pressure cause or creat any proplems?

Thanks again.

[Brian_UK]

Low gas pressure will cause incorrect burning as you won't have the correct gas velocity from the injectors to entrain the mixed primary combustion air to the burners.

Yes I agree with you the gas line is definitely undersized.

Good luck with it.