boiler modulator?

I have had problems with my boiler over the last few weeks. The boiler would stop heating the water and the hsi would click on and off like a light switch. The gas valve was opening and closing rapidly. Then when I reset it, it would heat perfectly for a few days - a week. I finally called for service and the repairman replaced the modulator and the hsi because it was worn from being turned on and off so much. My question is what is a modulator and what does it do for the boiler. I have researched to find out that it controls the water temp depending on heat load, but my boiler used to keep the water at 160 all the time, So I was wondering what it actually does. any help would be appreciated, Slowman

 

What boiler is it ? manufacturer, model , etc ???

What is an "hsi" ???

 

It is a pierless boiler. Its about 15 years old. I cant seem to find the model # and other important info. The hsi is (hot surface ignitor). It's no big deal. I was just wondering. It was covered by our local utility company insurace, so I really don't care as long as i'm getting heat. Thanks

 

I'm guessing here but the "modulator" may be an electronic module that over a period of cycles uses a bit less voltage to the hot surface ignitor so that the hsi will last a longer time. I know that my Lennox forced air furnace does this.

 

Yes, both ideas make sense. 1. the house warms up from a 15 degree setback much quicker explaining water temperature control and 2. controls voltage to hsi makes sense because the orginal issue was the ignitor cycling to fast like a light switch, thus not ignitiong the gas and causeing a lockout.
Thanks, everyone!

 

My guess is it is someones mis-pronounciation of "Module" as in ignition module.