I have a W-M boiler, 17500 BTU's CG series 12. There's percolating in boiler so I think it needs to be cleaned out. Also sounds like I have air in lines, but have been unable to bleed successfully. Now the boiler is getting up to temp but won't heat the house higher than 68F. Wondering if the pump may be going. It's VERY warm on electric side. Any suggestions?