Best way to monitor water temperature inside boiler.

skang

I have a hot water loop on my steam boiler that is used for baseboard heat. The aquastat for that loop is set to 170 currently, however it seems like it is getting hotter than that since it is heating up the steam section of my home even though that thermostat is not calling for heat. What's the best way to monitor the temperature of the water so I can verify what is going on? Also my understanding is that there is a minimum temperature for Steam boilers if I want to avoid corrosion. Some advice around that would be helpful as well. Thanks!

ImYoungxD

Pretty sure if you have steam and hot water heating in your home, the hot water will be 212 degrees since the water needs to be boiling for steam.

If the zone with steam heat does not call for heat, the hot water zone will heat the water up to 170.

Jamie Hall

Probably is getting hotter -- if the boiler is making steam, in fact it will be quite a bit hotter. Shouldn't make any difference. The hot water loop thermostat calls for heat, the circulator turns on, the thermostat gets satisfied, circulator turns off. End of story. The aquastat is there to make sure that the boiler water is always hot enough.

The hotter water -- for steam -- will just ensure that your hot water loop heats up faster.

As to minimum temperature. Most (if not all?) steam boilers are cold start -- they don't have to maintain a minimum temperature to avoid corrosion. What they do have to do is heat up enough when they are running -- which if they are making steam isn't a problem. Your aquastat should have a minimum temperature setting which will ensure that the boiler is always warm enough.

ImYoungxD

If you want to measure how hot your hot water baseboard is, get an infrared gun.

Jellis

Typically when you are overheating a zone like you are describing the problem is in the fact that hot water is circulating through your baseboard even when your thermostat is not calling for heat.
this could be due to a failed check somewhere in the loop, your thermostat could be bad as well.
when you turn down your thermostat or turn it off does your baseboard cool down? If your zone continues to heat I would disconnect the Thermostat and see if the condition continues.