Vitocell 300-v Recovery time

Tonerlow

Have a 42g Vitocell 330-v water tank. Heating unit is a Vitodens 220-w B2HB 94 

grundfos ups15-58fc circ pump to water tank. 

Is there any way to decrease recovery time of the water tank.  Would a larger pump be able to create more heat transfer? 

heathead

OK some questions? In the programing of the boiler the default is 27 degrees or so above current tank temp for the supply from boiler for IDWH recovery. That can be changed to increase water supply temp to tank for faster recovery. What speed is the 15-58 set to. With 94,000 btu you have a fair amount of energy that can recover that tank relatively quickly. What size pipes are running from the boiler to the indirect. You have to look at the pumping requirements of the boiler and be in those parameters if you change pumps. Does your tank have a mixing valve on the supply? If you need more hot water you could increase tank temp if you have mixing valve on the hot water supply to the house that would be my first choice.

Jamie Hall

Just for reference -- tne shortest possible recovery time will be 15 minutes.

Tonerlow

I still have 5 degrees I believe that I can increase the supply temp. As far as a mixing valve, I already have tank temp set to the max 60c. So there is no way there to increase energy storage. Pump is set to high. 1” copper lines I believe 

Tonerlow

@heathead I have a 26-99 pump currently running the heat to the house. So I’m assuming this pump fits within acceptable flow rates for the boiler and could be used on the DHW circuit also. The high rating on this pump is 33 gpm. The plumber basically told us we would have “unlimited hot water” when we spent the 17 K on the boiler installation and DHW tank. This is not the case as it stands right now. This is why I am looking for options to increase DHW output. Also by a quick google this is double the current flow rate of 17 GPM on the 15-58 pump.