Pump it off… hot water that is

​We have three Rheem gas hot water boilers at Freesia Gardens. When one boiler stopped working we ran the building on 2 hot water boilers for a period of 3 months. No-one in the 40 units in the complex complained. 

​We did replace the third hot water boiler but in the future we may be able to save energy by running the complex on just 2 boilers.

For the first 14 years of operation with these boilers we had a water pump circulating water around the building 24×7. When we measured the temperature of the water at the unit furthest from the boilers we noticed a drop in temperature of 10 degrees compared with the temperature at the boiler. This meant, each time warm water returned to the boiler, we were consuming energy to reheat it by 10 degrees before recirculating it again.

At first, we thought of installing a timer on the water pump so that hot water wasn’t continually pumped around the building between midnight and dawn. As our building is only 7 storey’s high we started experimenting with turning the water pump off altogether.We found that there was enough water pressure from the 3 hot water boilers to propel the hot water around the building without ANY water pumping whatsoever. The only downside is that the first person to have a shower in the morning might have to wait 1 and a half minutes for really hot water to arrive.
​
Turning off the hot water pumping has saved us electrical energy as the pump is NOT being used 24hrs a day. This also reduced our gas bill as we no longer reheat colder water entering the boilers during off peak times.

Brent Clark,
​CEO, Wattblock