Just want to have some advise on a boiler replacement.
Presently we have two oil boilers of 37 BHP. The boilers are really oversized and one is enough to heat the whole building. We want to replace one of the oil boiler by an electric boiler. We will control the electric boiler so that we stay under the peak KW demand. We have a good price for the kWH so it is advantageous to have an electric boiler that can meet some of the heat demand when we have a low KW demand in the building.
The oil boilers are in parallel between the supply header and the return header. There are 4'' pipes entering and leaving each boiler. We have three pumps that are pumping away from the supply header for the zones:
- Pump #1 is for a baseboard zone and gives 60 USGPM @ 40 head feet.
- Pump #2 is for a baseboard zone and gives 35 USGPM @ 35 head feet.
- Pump #3 is for a heating coil for the ventilation and gives 40USGPM @ 10 head feet.
The electric boiler has a 2'' pipe entering and leaving the boiler. I was wondering of the best way to install it.
1) Reduce the 4'' to 2'' and install the electric boiler in parallel with the oil boiler.
2) Use a Primary/Secondary arrangement for the electric boiler. Use a pump with closely spaced tees on a 4'' primary pipe joining the supply header and return header. The other oil boiler would be in parallel with the primary pipe that the electric boiler supplies.
3) Any other suggestions?