To find out what models you can use to replace the aquastat on your boiler, you will need to find the model number of your existing unit. You should look for this number on the unit itself, not on the cover. On Honeywell aquastats, the last four digits indicate the range of the dial and the length of the capillary. This information is important for choosing the correct replacement. The first part of the model number tells you the series.
You can find many different models of Honeywell Aquastats at www.supplyhouse.com
