Davegvg said:
The Master temp 400 requires massive amounts of gas- have a load survey done.
It cost me 4K to get a new meter and upsize the run to the back of the yard to make it work, but when its on - the level of heat is near nuclear from it.
Ive had a few issues with mine but its been running fine for about a year now.
Davegvg
The 400K heater should use roughly the same amount of fuel (just in a quicker time frame!) as a smaller heater, it just happens much faster as the pool/spa heats quicker and maintains heat better than a smaller heater would. Rough rule of thumb in my neck of the woods is that a 400K (I happen to have a StaRite; same as the Pentair but in an earlier period) consumes about $5.00 worth of Natural Gas an hour, based on my gas prices.
Check with your power supplier on the meter. They change (upgrade) the gas meters here for free (they are happy to think you will be buying more gas!). You can use an 1 1/2" line to run to the heater from the meter up to 75', but you need to size up to 2 inch line for greater than 75' runs, and less than 200'. Most applications fall well within those parameters.
I've never sold a smaller heater than the 400K (the 400 is only a couple hundred dollars more than the 250 or 335K units usually) for a pool or pool/spa combo. Bigger is better here, and you'll use the gas to get the temp you want one way or another
Bruce