Recent content by JezW

  1. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hmm just did some more tests. Temp was around 41c. Boiler temp set to 56c Flow out of the new hose, no head - 9.9LPM Boiler temp set to 60c Flow out of the new hose, no head - same - 9.9LPM The increase does seem good for the £££ spent. Although I'm wondering if I calculated the flow rate...
  2. J

    Mains booster pump to increase shower flow rate from combi boiler

    https://www.amazon.co.uk/dp/B01F3UL1PY?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
  3. J

    Mains booster pump to increase shower flow rate from combi boiler

    New hose! Cold (7c) Flow out of the new hose, no head - 13.5LPM ! (must have some measurement error) Flow out of the new hose, with head - 12.9LPM Hot (approx 41c, ΔT = 34c) Test 1: Flow out of the new hose, no head - 9.6LPM Test 2: Flow out of the new hose, no head - 10LPM So...what does...
  4. J

    Mains booster pump to increase shower flow rate from combi boiler

    Just by dropping the shower hose actually! The flow is the same with the hose, and with the hose + head. New hose arrives tomorrow. Will report back! :D
  5. J

    Mains booster pump to increase shower flow rate from combi boiler

    Nice calculator! But a 7mm bore hose loses 0.8 bar? That seems very high!? I think my current hose is longer than 1.5m as well..
  6. J

    Mains booster pump to increase shower flow rate from combi boiler

    Just double checked, no restrictor in either end of the hose. Bore is about 7mm, tested with a drill bit, good idea thank you :) Just ordered a large 11mm bore shower hose. Maybe that sorts it!
  7. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hi John and Trojan I think ignore those slightly dubious figures. I've just done some more tests... From the basin tap: 7.5LPM From the shower, hose attached, no head attached: 7.5LPM From the shower outlet in the wall, no hose or head attached (bottom right of below photo): 12.6LPM ! So the...
  8. J

    Mains booster pump to increase shower flow rate from combi boiler

    Haha I'm getting a bit lost John! The tests that you are suggesting - what will they tell us? Are we just trying to work out the maximum possible flow rate through my shower? I'm pretty sure this is my shower mixer and these mixers should allow high flow rates -...
  9. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hi John Just did that - dropped combi temp to minimum (35c), and shower temp to maximum. Flow rate through the shower is 6.5LPM. What does that tell us? I would've expected the flow rate to increase...not decrease!
  10. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hi John, thanks for your reply and those calcs! Gotcha - so the max flow rate through my 25kw combi, with desired temp of 40c and cold mains of 7c, is 25*860/60/(40.0-7.0) = 10.86LPM And if we do this calc for a ΔT of 35c: 25*860/60/(35) = 10.23LPM, which interestingly is slightly below the...
  11. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hi Muggles What's the point of vaillant stating a flow rate of 10.4 l/min with a temp increase of 35c, if the max flow is limited to 8 l/min? :rolleyes: However, if I can get 8 l/min through the boiler (instead of 8.4l/min in my third point above), and that's 70% of the flow rate going to the...
  12. J

    Mains booster pump to increase shower flow rate from combi boiler

    Hi all I'm in a first floor flat and the shower pressure/flow is pretty poor. At a temp of 40c, the shower flow rate is 7.5 l/min. The cold mains is 8.4 l/min. I'm thinking about fitting a mains booster pump like this: https://www.salamanderpumps.co.uk/products/mainsbooster/homeboost/ They're...
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