I've been having boiler problems at my duplex. The first problem was no heat. HVAC tech replaced the aquastat (online) and the system worked for a couple of hours then pressure relief valve "popped". Next day the HVAC tech replaced the online aquastat with an inline unit. Everything seemed fine, but I received a call this morning from 1st floor tenant than he had no heat (Thermostat was set to 75 but Apt was only 60). The HVAC tech came back out and adjusted the Temp/limit setting (to about 190 on 180 off). The baseboard units were all receiving heat but they still do not seem to be as "hot" as they should be. There is no air in the system and the 2nd floor is heating fine. Although the system "seems" to be working properly, I'm wondering to myself if I'm missing something. Any ideas? Thank you.

I have a boiler which constantly shuts off. It has done this since new (4yrs) I replaced the boiler as soon as I moved into this house because the old one was shot so I dont know if this happened before. Its a Carrier steam boiler (radiators) and shuts down evertime the preasure gets to 6pds. then it shuts off untill the preasure drops then refires. Everone who looks at it says its needs cleaner then ethier they or me add cleaner and let the boiler run for a week then drain but the problem dosent go away, Any suggestions. The house is a small cape style.