Cold water getting into the secondary return?

[Max31198]

Cold water getting into the secondary return?
Hi there, help please how is it possible for cold water to get into the secondary return flow back to the boiler.

I have a large house and a 300 L tank I have noticed that when I turn the hot tap on that the temperature on the secondary return Pipe to the tank cools rapidly. However if I turn off the cold water supply to the same circuit i.e. the first floor, then the temperature doesn’t drop. I hope this question makes sense?

 

[ianmcd]

is it a dedicated secondary return tapping or is the secondary return teed into the cold water inlet ?

 

[Max31198]

I don’t know the answer to that but my question would be in what circumstances would it be teed into the cold water system?

With the exception of a couple of outlets and some taps all the showers and baths have hands grohe I boxes installed.

 

[Bodd]

I don’t know the answer to that but my question would be in what circumstances would it be teed into the cold water system?

With the exception of a couple of outlets and some taps all the showers and baths have hands grohe I boxes installed.

As the cold water feed inters the cylinder at the bottom.

Has a non return valve been fitted in the secondary return?

 

[ianmcd]

some cylinders come with dedicated secondary return tappings , some dont and the cold water feed is used, not the best way to do it but it is common, if doing it that way a non return valve should be used, still not correct but will work, post a pic of your set up

 

[Max31198]

 

[Max31198]

As the cold water feed inters the cylinder at the bottom.

Has a non return valve been fitted in the secondary return?

No not that I can see

 

[muggles]

Actually looks to be a generally decent install but needs a non-return valve fitting to the secondary return pipework

 

[Bodd]

No not that I can see

I think that may be the answer to your problem