Old Radiant Heat w/ a Navien Gas Combi Unit

BravoBravo

Hi!

I have a 1 year old navien gas combi unit. It provides heat to our first floor radiant heated floors. During the cold snaps that fall below 28 degrees F the heat in the house drops from 72 to 68. Is this because it is not strong enough to provide a good continues heat? Our previous unit was a powerhouse furnace. With very few hiccups until it died 20yrs later. I have noticed the pipe that feeds the radiant heated floors is super hot yet the return pipe stays cool. The floors stay warm but no where near as warm as when the furnace was installed. Would love to get some insight. Positive input is super appreciated.

Jamie Hall

Need to know something about the size of the two boilers — BTUh ratings… It's rare for a replacement to be undersized, but it does happen.

hot_rod

what type of radiant,in slab, under wood floor? Was it a retrofit? Was a heatload and system design performed?

GGross

radiant heated floor supplies are generally not super hot. What temperature is is the boiler making? can you take a couple of pictures of the system?