Combining Unvented Cylinder and CH Discharge?

13 Sep 2015
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North Lincolnshire
United Kingdom
Hi Chaps,

I'm having a new CH system fitted soon, which will include an unvented DHW cylinder.

This will naturally have discharge pipework for the pressure relief and combined P&T valves, and I understand the pipe sizing and tundish requirements for those.

The CH system will be sealed, so will also have its own pressure relief discharge requirements. The question is: can this be combined with the DHW cylinder discharges, so that there is only one "D2" discharge pipe going through the wall?

If so, how are the pipes best combined, and what pipe sizes should be used? The cylinder and CH pipework will all be located in the same (fairly cramped) space.

The installer is registered for unvented installations - this is just for my own understanding!

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