I am just about to move back into a house I used to rent out, I had to replace the boiler several months ago and got a "billy basic" model. I have been told by many people that I can't get more than about 1.5 bar from a combi, and that a large shower head and body jets are out of the question. Surely it isn't. I'll just have to do something to boost the pressure. Is it possible to get a combi that doesn't restrict the mains pressure ? I am assuming that mains pressure is about 3 bar ? Can I fit a pump ? If not why not ? I noticed that other conversations have touched on the subject, but don't seem to have answered my questions. Thank you guys and gals.
Big shower head, body jets and a combi ? Can it be done ?
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you will get whatever the mains pressure is
its the flow that is restricted to allow the boiler to heat the water as it passes through
no you cant fit a pump as its connected to the mains its not allowed
its the flow that is restricted to allow the boiler to heat the water as it passes through
no you cant fit a pump as its connected to the mains its not allowed
B
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Sounds like you haven't bought/fitted the shower yet. What can your boiler deliver and what do the shower makers require? Should give a big clue.
pressure is probably not your problem - your problem will be FLOW RATE.
A typical mains pressure shower (eg mire excell) uses 10 litres per minute of 55 deg C water for the HEAD only.
A bog standard combi boiler will deliver 10-12 l/min over a 35 degree rise - i.e in winter you might get 12 l/min of water at 40 degrees C - if you are lucky. (40 degrees C is warm, but only just - typical shower temp 43-45 deg C)
When you add in your body jets as well, I think a combi boiler will struggle to deliver enough flow rate.
CCM
A typical mains pressure shower (eg mire excell) uses 10 litres per minute of 55 deg C water for the HEAD only.
A bog standard combi boiler will deliver 10-12 l/min over a 35 degree rise - i.e in winter you might get 12 l/min of water at 40 degrees C - if you are lucky. (40 degrees C is warm, but only just - typical shower temp 43-45 deg C)
When you add in your body jets as well, I think a combi boiler will struggle to deliver enough flow rate.
CCM
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You like a hot shower CCM! Shower mixers are usually stopped at 38º above which you have to press a button to go. Bath is about 45.
I know someone with a 8 inch showerhead and a combi , but it's a WB Highflow, which has a biggish store of hot water which can come out at a much higher rate than a standard combi - about 18 litres a min I think. While the store is being used it's okay, just, but when it gets the boiler's 24 kW worth, you get a very poor looking flow.
You don't even get enough imho from an unvented cylinder. Local to me I put one in all on 22mm pipes, 3 bar mains, and the fairly normal shower (grohe) gives 18 l/min.
If you use a huge store of HW and pump it with a £450 pump, you'll get the 30-40 l/min you find in some hotels.
I know someone with a 8 inch showerhead and a combi , but it's a WB Highflow, which has a biggish store of hot water which can come out at a much higher rate than a standard combi - about 18 litres a min I think. While the store is being used it's okay, just, but when it gets the boiler's 24 kW worth, you get a very poor looking flow.
You don't even get enough imho from an unvented cylinder. Local to me I put one in all on 22mm pipes, 3 bar mains, and the fairly normal shower (grohe) gives 18 l/min.
If you use a huge store of HW and pump it with a £450 pump, you'll get the 30-40 l/min you find in some hotels.
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