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New central heating issues

GJW Member Posts: 1
Hi, I have just had my system "upgraded" but issues with it are worrying. Everything apart from the boiler ( Valiant eco tech plus 424) and filter (Magnaclean) have been renewed. The new system is now in three zones, downstairs heating ( 6 radiators ) upstairs heating ( 4 radiators plus bathroom towel rad ) and hot water to a new tank. It has also been changed from an F & T open vented to a sealed pressurized system. The 22mm pipework to / from the boiler has been extended so both down and upstairs heating circuits have shorter 15mm runs to the rads. It also has a new Grundfos UPS3 pump. Running pressure is 1 -- 1.5 bar.
Issues, the whole system is noisy Ie hissing TRVs and pump. TRVs are only working at setting 5 to 6. Some rads ping a lot when the hot water goes in. There is some air still in the system but not enough for these issues.
My thoughts are, is the system circulating hot water too quickly to the rads now the main 22mm pipes have been extended. Are TVRs struggling to control with a quick change in water temperature. Is the pump flow too high even on its current setting of 1 ?.
Any thoughts or help gratefully received.


    EBEBRATT-Ed Member Posts: 14,560
    a lot going on here including metric conversions can you post a sketch? And can you explain the open system to closed system conversion?
  • mattmia2
    mattmia2 Member Posts: 8,893
    I think the UK hung on to their open expansion tanks in the attic a lot longer than we did in the US. Here they became obsolete by about wwii and were replaced by compression tanks and later bladder tanks.
  • hot_rod
    hot_rod Member Posts: 20,827
    The UPS 3 has a lot of adjustability, properly set up I don’t see it over pumping.

    Maybe an air problem, or an isolation valve not fully open or the stem broken off. Hissing is sometimes water being pushed through a small opening, kinked tube, etc.

    In the correct mode that pump should modulate down to near 0 flow rate
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream