Central Heating circuit advice.

[Christian and Beccy]

The renovation of my bungalow has been going on for several years and along the way I've re-piped the entire Central Heating system.

For right or wrong, the main circuit is 22mm, with the branches in 15mm. Every inch is insulated. I understand this is likely to be overkill. Now I'm nearing the end, I want to be sure that I complete the circuit in the correct way. This is only a bungalow with about 8 or so rads.

Now, I understand that usually the last rad would serve as the end of the circuit, so the final section of the supply pipe would go in at TRV end, and the return run would begin at the other end picking up all the other rads on the way. However, since my main circuit is entirely 22mm, by ending the circuit across a rad would serve as a reduction in the 22mm system, so would it be acceptable for me to essentially join the supply and return pipework making a continuous 22mm loop and branch the last rad off as all the others?

 

[RickMoore]

Once your system is complete you will balance it to achieve the correct flow rates through the system.

If you connect the flow and return you will just bypass your radiators and cause your boiler to cycle. The object is not to get as much hot water firing round the system as fast as possible, you want it to loose enough heat along the way so your house actually gets warm. Reduce the ends of your 22mm pipe to 15mm and connet to the radiator. Everything else you have done sounds just fine.

 

[Christian and Beccy]

Perfect. That makes a lot of sense.

Thanks.