Aquastat Relay?

[Loafer]

I am having a problem with my furnace it is a forced hot water system using old cast iron radiators. The burner will turn on when the thermostats call for it but the circulators will not turn on. If I tap on the aquastat relay (Honeywell L8148A0) a few times they will start for awhile usually until the burner lights again then the circulators will shut down again. Is there anything I can do short of calling a burner tech. It the relay repairable? What will it cost to have installed?

Thanks Scott

[RBM]

[Mikepier]

Is this the aquastat you have? This was the closest thing I found.

It sounds as if the switching relay might be dirty or have corrosion on the contacts. you can try cleaning it, but shut the power first when you do.