Pool Heater: right BTU size for gas pipe
We are remodeling our pool and we were supposed to get a Jandy Legacy 400K BTU heater. However, our pool guy said that our gas pipe is too narrow for 400K.He wants to give us a Sta Rite heater with 300K or 200K BTU. However, I have heard that Jandy is a superior brand in terms of heaters.
The total length of the gas line is about 90 feet from the gas meter to the valve. The first 45 feet from the meter have a diameter of 1" and the following 45 feet to the valve have a diameter of 1.25" (the previous owner must have extended the gas line at some point after an add-on to the house). Our gas meter is pretty old and will be replaced.
Do you think the 400k BTU heater would work with this gas line? - I do not want to end up with an inferior product and less heating power. Would there even be a disadvantage if we went with the 400K BTU heater even if the gas line is too narrow? The heater would then just never run at maximum power/capacity...
If the gas line is an issue: Could we go with 400K BTU if the gas line diameter was 1.25" all the way?
Thank you so much for your advice in advance!