M
marsaday
Do you need to put the combi hot water feed in 15mm or 22mm. Someone mentioned it needed to be 22mm, but i thought 15 was fine?
It could depend of the system, but generally you would expect.
*15mm to cold water inlet
*15mm to hot water outlet
*22mm to flow/return C/H
*15mm to cold water inlet
*15mm to hot water outlet
*22mm to flow/return C/H
A lot of combis out there will have a 15mm inlet on the cold water inlet.
Its not as simple as "it's a 15mm connection so 15mm will do". Each system needs to be carefully considered as you may have low flow rates, poor pressure etc.
In cases where there are issues, you may see 22mm (rarely larger) run up to the boiler and reduced at the last point to 15mm. The vast majority of combi boilers will operate fine on a 15mm main where the pressure and flow is adequate.
Its not as simple as "it's a 15mm connection so 15mm will do". Each system needs to be carefully considered as you may have low flow rates, poor pressure etc.
In cases where there are issues, you may see 22mm (rarely larger) run up to the boiler and reduced at the last point to 15mm. The vast majority of combi boilers will operate fine on a 15mm main where the pressure and flow is adequate.
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