Heater Gas line size

[gatorson]

My previous plumber installed my sediment trap about 6 feet away from the inlet of the heater (directly out of the source line). He also installed a regulator/governor and reduced down to 1/2" pipe for a length of about 6ft to my 400k NG raypak heater (the distance from the meter to the dedicated regulator is about 75 ft and is 3/4" pipe). The heater then goes back up to 3/4" pipe into the gas valve. My question is it ok to have this short distance of 1/2" pipe and also have the sediment trap a short distance from the heater? Every video and manual shows the sediment trap directly outside the heater. The heater fires up properly, but am I starving it for gas? The plumber stated that he has high pressure and that's why he had to install a dedicated regulator right after the source coming from underground and that the 1/2" pipe is "fine".

Should I request to replace the 1/2" 6ft pipe section with 3/4" or is the way it is currently plumbed ok?

Thanks!

 

[PoolGate]

I'd say your plumber probably knows what he's talking about. Fuel starved heaters are actually dangerous so I doubt he'd do something that caused this condition.

 

[JamesW]

reduced down to 1/2" pipe for a length of about 6ft to my 400k NG raypak heater

1/2" pipe is too small.

Have the plumber do it correctly.

Below is the quote from the manual, which has to be followed.

*A 3/4" gas line can be used for up to 5' (1.5 m) maximum length from the gas valve in addition to the sediment trap

 

[Futuresvt]

What pressure is your gas line? 7 inch water column or 2 psi? If you have a regulator just before the heater than you might have a 2 psi setup. Do you have a regulator on each appliance in the home?

 

[JamesW]

What pressure is your gas line? 7 inch water column or 2 psi? If you have a regulator just before the heater than you might have a 2 psi setup. Do you have a regulator on each appliance in the home?

They indicate that it is a two stage system with 3/4” pipe at 75 feet from the meter to the second stage regulator. Based upon an inlet gas pressure of 2 psig at a pressure drop of 1 psi, the first stage at 3/4” is good up to 150 feet. From the second stage regulator to the inlet of the heater gas valve can be 3/4” up to 5 feet assuming an inlet gas pressure of 10 in-wc at a pressure drop of 0.5 in-wc.

1/2” is unacceptable. Any warranty can be voided based on improper installation.

Note that the pipe length is “total equivalent length”, which is the length of all straight pipe plus a standard length equivalent for each fitting.