Sudden drop in pressure in gas line or bad gas meter.

[idreos]

I have a problem with my 3 year old gas furnace.

Last Sunday I smelled natural gas outside my house and found the smell coming from the PVC furnace exhaust pipe on the side of my house. The gas company responded and said the furnace had to be tweaked. My HVAC contractor came the next day and diagnosed the problem as an abrupt drop of pressure from the gas pipe when the furnace went into its second stage of ignition.

When the furnace comes on it initially produces a steady flame but the pressure drops from a 7.5” at 1st stage start up and drops below .5 90 seconds later when the furnace burner goes into its second stage. The HVAC contractor said the problem was the gas meter.

A gas company rep came back and tested the meter reporting that the gas meter was delivering a steady 7.5 pressure reading and that the problem likely lies in the gas pipe from the meter to the furnace in my basement.

The gas piping from my gas meter comes into my house in a straight 10 foot run to my gas furnace

Two feet from the exterior wall entry the black pipe has a t connection with a run to a gas dryer.

The gas dryer works fine but the 3 year old gas furnace has a supply problem.

Is it possible that an obstruction suddenly occurred in the black pipe after three decades?

Has anybody familiar with gas piping ever heard of a gas pipe obstruction that could cause such a pressure loss.
So long story short the gas company is saying my pipe is at fault and my contractor is pointing the finger at the gas meter.

I am concerned because the furnace will be needed soon and am uncertain as to how to proceed with my HVAC contractor and the gas company blaming each other.

Any suggestions on what is causing this problem or any testing or work needed would be greatly appreciated

 

[Bgard]

Is the contractor testing the pressure on the inlet or olet of the valve?

 

[Sponsor]

 

[Plumber69]

By chance is there any copper gas line in your gas system at all. Was the drip leg checked and the screen on the gas valve checked

 

[idreos]

Are you talking about the gas valve on the furnace?

 

[idreos]

By chance is there any copper gas line in your gas system at all. Was the drip leg checked and the screen on the gas valve checked

No copper lines all black pipe

 

[Reach4]

Is it possible that an obstruction suddenly occurred in the black pipe after three decades?

Has anybody familiar with gas piping ever heard of a gas pipe obstruction that could cause such a pressure loss.
So long story short the gas company is saying my pipe is at fault and my contractor is pointing the finger at the gas meter.

https://terrylove.com/forums/index.php?threads/gas-line-pressure-drop.72161 is about a system that has not worked yet.

 

[idreos]

Thanks for your responses
The pressure was tested at both the furnace's gas valve inlet and outlet.
Both showed the same sudden drop at the second ignition stage.
A tech with over 35 years experience with gas believes its the gas meter regulator.
Calling the gas utility company again. This is a very frustrating problem. The three gas co. techs who have come to examine the gas meter on THREE different occasions in the last two weeks seem to lack the technical knowledge to realize that the gas meter has a bad regulator.

 

[Dj2]

Thanks for your responses
The pressure was tested at both the furnace's gas valve inlet and outlet.
Both showed the same sudden drop at the second ignition stage.
A tech with over 35 years experience with gas believes its the gas meter regulator.
Calling the gas utility company again. This is a very frustrating problem. The three gas co. techs who have come to examine the gas meter on THREE different occasions in the last two weeks seem to lack the technical knowledge to realize that the gas meter has a bad regulator.

I find it strange that the gas company techs did not replace their regulator already. Call the company and ask to talk to a manager to get something done. You are paying for service, its their equipment...why the delay?
My gas company will go out of its way to help a customer.