[an error occurred while processing this directive]
Posted by Dave on December 05, 2005 at 18:29:57:
Here is what I did today to test recovery time with my Phase III at reduced boiler temp.
I ran hot water into jaccuzzi for 6 minutes with boiler turned off. I then went downstairs and turned on boiler and timed how long it took for Phase III to reach temp of 130 degrees for DHW.
The first time was with the boiler temp set to 180, but with only 150K btu stage running. (I have had second stage of burner off all winter so far). The second time I performed the experiment with the boiler temp at 150 to simulate buffer tank at low end of its temp range.
With boiler temp set to 180, it took about 5 minutes for water temp in boiler outlet to come up to 140 degrees from a cold start.
It took a total of 17 1/2 minutes for Phase III to reach 130 degrees.
With the boiler temp set at 150, it again took about 5 minutes for outlet temp to come up to 140 degrees from cold start and a total of 22 1/2 minutes for the Phase III to reach 130.
Do these numbers seem reasonable? I would assume that 150 degree water being used to heat DHW from the buffer tank into the Phase III would be a worst case scenario, as the buffer's aquastat would be set to fire the boiler at 150.
In the first situation with the boiler temp set to 180, the boiler ran the entire 17 1/2 minutes, but in the situation where the boiler temp was set to 150, the boiler cycled on and off 3 times as it was able to reach 150 and shut off.
Of course, if I had the second stage of the burner turned on, so all 300K btu's were being put out, both times probably would have been faster.
What do you think?
Post a Followup