Oil fired burner w/ \"booster\" electric HW tank question

Norm Harvey

Thats done a lot in MA.

What happens is as you draw hot water, the cold water that has to replace it is drawn through the tankless coil in the boiler before it is deposited into your electric tank. Its a little free heat in the winter for your hot water, and your electric elements in the water heater dont have to work.

The boiler comming on is most likely because there is still a low limit control on the boiler keeping the boiler at a minimum temperature.

Some old boilers may leak if the low limit is taken out of service which is why many people just leave the low limit on and turned down as far as it will go. Below 120.

If your boiler doesnt leak if you were to shut the emergency switch off for a day than you could save some fuel by switching to a cold start control such as a Honeywell L8148

Joe_114

Oil fired burner w/ \"booster\" electric HW tank question

I have an oil fired boiler providing heat to our home through a combination of radiators and baseboard units. The boiler also provides hot water to a "booster" tank for DHW. The booster tank is basically a 50 gallon electric hot water heater plumbed in to the boiler. This system was in place when we moved in this past summer. Since we've moved in, I have noticed that about every 20 or 30 minutes the boiler will cycle on for maybe 45 seconds and then turn off. I replaced the thermostat recently w/ a programmable unit, so I know it's not the thermostat calling for heat (no heat is felt coming out of the radiators/baseboard units during these short cycles either). I'm guessing this is a wiring issue between the HWH and the boiler, does this make sense? The upper and lower thermostats on the HWH are both set to 120 degrees. Should the HWH be calling for warm/hot water from the boiler even when there is none being used for showers, dishes, etc?

Thanks,

Joe