Not sure if my boiler is running correctly

corey_s

I bought a new house and moved in about a year ago. The boiler is a Burnham P204-WI with big cast iron radiators. It's old but seems to work well and keeps the house comfortable. I've noticed a lot of talk on here about return temperatures and corrosion. It looks like most people have a return temp far above my max temp. My boiler cycles once an hour and completely shuts down after each cycle. Before a cycle begins the water temperature is close to room temperature. The hottest I've seen it get before shutting off is only 120. Is this the way my boiler should work? This seems a lot different than what others are describing. Please let me know what other info you need. I'd appreciate any input.

Ironman

What your describing is not unusual for a system that has cast iron rad's and large pipes that were gravity flow. There's a huge amount of mass there which means it takes a good while to heat up and a long time to cool down as it gives off its heat.

Systems like this typically don't see a SWT of over 140*.

If you're seeing any corrosion coming out of the flue pipe, then some form of boiler protection should be employed. A simple bypass pipe at the boiler is the easiest to install, but not necessarily the best method.

By the way, a new mod/con boiler would be very efficient on a system like yours with its high mass and low SWT.

corey_s

Ironman said:

What your describing is not unusual for a system that has cast iron rad's and large pipes that were gravity flow. There's a huge amount of mass there which means it takes a good while to heat up and a long time to cool down as it gives off its heat.

Systems like this typically don't see a SWT of over 140*.

If you're seeing any corrosion coming out of the flue pipe, then some form of boiler protection should be employed. A simple bypass pipe at the boiler is the easiest to install, but not necessarily the best method.

By the way, a new mod/con boiler would be very efficient on a system like yours with its high mass and low SWT.

Thanks for the input. I just wanted to make sure the system is working properly. Is 1 CPH the correct setting for a old gravity system that was converted and had a pump added? It looks like in another thread you said that Honeywell recommended 1 CPH for a converted gravity system.

Thanks.

nicholas bonham-carter

For hot water systems, the CPH is usually set to 2 or 3.—NBC