Correct, which is why I went through the exercise of trying to determine what the OP's system would look like in the first minute of operation from a cold start.KLook wrote:Your boiler works on the same principle as the on demand water heaters. You can spit cold water through them at full speed and they heat it up. But it is pushed through small ports that get the water in contact with as much exchanger surface is possible and I guess they create condensation and have short lives if the water is hard.
Ours work on having large water storage and matching the flow(btu's/gal = flow/min) @ X temp. If you are feeding radiant heat, then you can circulate all the 140 water you want. If you are feeding baseboard, toe kicks, and cast iron like I am, you better have a min. of 160 and that is after some hotter stuff has already gone out and put out some heat where demanded. I have a radiant slab also but it is an injection system and always has enough heat in the water to work.
Kevin
If he's returning 150f water to the boiler, and if it's heating water at a rate of 1000btumin, then there isn't any reason, aside from poor boiler design, that the water in the system will ever drop below a low limit threshold of 150f.
Also, he's in the heating season, so while I used 86 degree water in the pipes, in actuality it should be higher because of the constant calls for heat.
The circulator on my boiler is capable of putting out almost twice the capacity of the boilereach minute. I don't think the boiler is that efficient.