Gas burning furnace flue height in nyc

[Tony Peluso]

OK this is my first post. I am a home inspector in nyc and came across this proplem. Customer calls and said on windy days there furnace (hot water system) and hot water tank pilot goes out. Not both at the same time and not all the time, they even on occasion have to reset the spill swich. Plumber goes there and changes both thermo couples no good.They call me and I think maybe they need some high wind cap on the flue so I go take a look. This is a condo in brooklyn. I go on the roof and find the flue in question is on the roof that is somebody terrace. The flue is not in a windy area but in a corner with three other flues three feet from a wall that is the other apt. My questions is this, first is this a violation because of clerance and is this the reason for backdraft Thanks new guy on the block

[Billy Stephens]

Welcome Tony,

Glad to have you here.

See attachment page 21 figure 43.
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[Tony Peluso]

Thanks Billy I appreciate your help. The customer has been having backdraft issues for a while. everyone was saying it was wind or thermocouple but when I went out to the property the flue was on another tenants terrace about three feet from a wall surrounded by evergreens in pots. At that point I thought that there was little wind and had to be something else. Thanks Tony Peluso METROPOLITAN HOME INSPECTION

[Dave Wheeler]

Tony,
I don't know if you resolved the problem yet but did you check for proper fresh air and if there is an exhaust system in the home that is creating a vaccum? Can you post the solution if it was found.
I hope this helps,
Dave Wheeler :) MDA Home Inspections NYC

[Jaime Fushille]

Good morning!
Here's a question I cant seem to find the answer to in the IRC:

How high over an evaporative cooler must a gas vent terminate?

According to the code, gas vents must terminate not less than 2 feet higher than any portion of a building within 10 feet. Based on that rule, I've been using that standard 2 feet over adjacent coolers as well.

Anyone have anything else on this?
Thanks in advance!
Jaime Fushille

OK, I think I found it in the International Mechanical Code:
according to the International Mechanical Code 804.3.5-2, “Vents shall terminate at least three feet above any forced air inlet located within 10 feet. Extension of the vent is recommended.
Thanks