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  1. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Ran a few showers earlier and opened up a third outlet....the boiler was registering 18-18.5lpm so something has freed things up. It seems the more outlets open the higher the flow rate it registers Previously doing this I think got 10-11lpm maximum regardless of how many open. A single outlet...
  2. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    A quick update as things are moving in the right direction at last and I'm grateful for the help here. Fitter came out and measured the flow rate at the boiler to be 20lpm. Navien visited earlier and the chap tried several new flow restrictor devices so as pointed out earlier in the discussion...
  3. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Thanks for that. Little bit of progress...Navien are coming to see the boiler with the installer...not sure when yet but hopefully very soon so will be interesting to see what they say and whether they consider any testing like the above. Will definitely report back.***
  4. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I just gave that a try....ran the shower in the ensuite in the loft as that is the furthest away of the two. There was minimal difference for some reason and both temps hovered around the 5.8lpm mark on the boiler display....the lower temp exceeding it intermittently. The shower itself has a...
  5. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Well, no contact from the fitter as yet although an electrician was here fitting some opentherm controls as part of the deal. Checked again at the outside tap and confirm it was still 22lpm. I did try the washing machine inlet hose and that didn't quite match the 22lpm and was around 17.5 but I...
  6. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Yeah I agree....the only time I've managed to get a higher flow rate reading on the boiler screen is when I've opened a few hot outlets. A single outlet stays around the 9-10 mark.
  7. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    The Istor never suffered from this issue so could this issue possibly be installation related? Seems strange how all of a sudden the flow rate has dropped after installation of a new boiler. The Istor even had a prv limiting the pressure....this doesn't and have anything limiting on the supply...
  8. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Just followed your instructions nice and straightforward thanks. Although the boiler has a dedicated feed in 22mm pipe using that method I get spot on 9lpm....which corresponds nicely with the boiler readouts. I gather this is why I'm not getting the desired flow rates?
  9. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I'm going to ask the fitter to do this for me as I'm a bit uncertain how to go about it. Funnily enough I did ask him to do this during the installation before connecting up the boiler but he didn't have a flow cup on the van!
  10. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Was hoping to reply this eve with some info from Navien as I was contacted today by the boiler fitting company saying the installer had spoken to Navien earlier today. No phonecall as yet so I can't really update. Yes previously the ideal istor was an all in one unit of a 24kw system boiler (an...
  11. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I will clarify the page 23 with the installer so thanks. I've just attached the PG to the point just after the stopcock....today around 15 mins ago it measured 2.2bar. Assuming it must fluctuate if I got 3 bar previously an outside tap. (The outside tap was the same 2.2bar btw) cranked up the...
  12. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Had a quick look at the manual I have here and there's no mention of flow restrictors just something about cleaning the return adaptor filter on page 51 which I assume isn't it? I've attached the manual it would be great if you had a sec to see if there's anything obvious that could have been...
  13. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I'll check for that in my manual tomorrow and ask the fitter to reclean the filter assuming the flow restrictors can't be cha he'd or removed. Much appreciated
  14. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I'll try and do this. Think there is a point where the mains enters the property where I could attach a gauge and take a reading. Not sure about after the boiler though in terms of attaching to taps etc but will look into it. Thanks
  15. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Don't think so although I'll have another good read tomorrow. I've kept an eye out for flow restrictors but not filters so will have a good check. Thanks
  16. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    I've also noticed the boiler has a read out for central heating pressure. This might be irrelevant but it reads at 1.25 bar.?
  17. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Thanks for that. In terms of the cold water supply pressure and potential restriction, the run from the incoming mains tees off two ways - one in 22mm that runs direct to the boiler . Probably covers 40 feet or so. The other again 22mm runs off to the cold outlets (but turns into 15mm after 15...
  18. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Just opened two hot taps - one in a sink next to the boiler and one in a sink upstairs in the kitchen (boiler in basement). kitchen was 5.4lpm and basement tap 7.2lpm - the display on the boiler was just passing 12lpm which was progress in some ways. the water temp is 47 degrees so a 37 degree...
  19. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    That's exactly my issue. He told me 40kw was ideal. Had I have know I'd get 9 or 10lpm I would never have gone this route or saved a few hundred quid and got a smaller boiler. Just to be certain, when/if he returns what should I be suggesting he do exactly (without telling him how do his job!?)
  20. E

    40kw Navien NCB Combi install with v.poor DHW? Is this adequate?

    Great - apologies though - which valve are you referring to as I'm not overly familiar with all of this? So supposedly if I release the hot water from this valve I should hope the lpm reading on the digital display would increase and show a true reflection of what the boiler is capable of...
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