L
leonslater77
Hello world! A bit of history on the job first. Existing boiler Gloworm 24HXI 8 yrs old never serviced. Customer has been having problems for 3 years with heating, not getting hot, boiler banging etc. Anyway HXI heat exchanger has had it, (seen a few of these now waterways cant handle much) No heating for a few weeks. I have replaced the boiler with a Veissmann 100W 27KW heat only open vent boiler. 13 rads throughout 5 bed house, 28mm primaries to cylinder and heating system. I cut out the air separator, installed new 15/60 grundfos pump. System now much improved but the boiler modulates as if there is a restriction in the pipework, thus rads don't get to that red hot to touch stage. I cut the primary flow and return pipes and blew down and there seemed to be no restriction or real resistance. Connected my powerflushing machine to Flow and return to boiler, filled and fired up. Boiler runs like a dream up to 80 degrees so boiler all working perfectly. The only thing ive noticed when cutting into some sections of the flow in the airing cupboard is that the 28mm pipework is lined with hardened sludge. Its not completely restricted by any means but could the hardened sludge and the roughness of it cause enough resistance though the pipework to cause the flow through the boiler to slow down. Any thoughts are welcome as I am second guessing myself. After 15 years plumbing there's always something that stumps you. Oh and I have arranged for Pflush to do a full powerflush of the system in 2 weeks, its expensive but the rads are about 30 years old and due to that hardened sludge this has to be done. Plus I've told the customer I wont leave their system until its working perfectly. Cheers People!
