We just installed a Central Boiler OWB 2 weeks ago. Everything seemed to be working fine up but now it seems we run out of hot water. We have a sidearm heat exchanger hooked up to our oil 30 gallon water heater. I read the other posts here on this topic and from what I understand from them, I would believe it is working fine. The horizontal pipe that runs out of the top of the exchanger to the anode port on the tank is extremely hot. The water as you first start using it is also extremely hot. If you make a constant draw of hot water though (eg. 2 showers in a row), you lose the hot water. At times you can go to the bottom of the exchanger and draw water out that is extremely hot and sometimes it really isn't. I turned the oil burner back on but set the thermostat to 100 degrees and on a constant draw, it will kick back on again. Can someone think of something that can be wrong? We drained the tank to install the exchanger which I would imagine took care of the sediment on the bottom of the tank. The anode rod was quite a site though, looked like white swiss cheese. We purged the air out of the tank (or so we thought we did) at the top elbow of the exchanger set up. Any help would be appreciated.