Expansion tank piping

[SimonD]

I'm planning to fit a hot water expansion tank. The existing pipework is polypipe (or similar) but is there any reason why I shouldn't use normal reinforced flexible hose to tee in the tank? It would make the plumbing a bit easier.

 

[vyv_cox]

No reason at all. My complete system, including accumulator on the cold side and calorifier, is plumbed in caravan type reinforced hose, red and blue.

An accumulator in the hot water is normally only needed if there is a NRV in the cold water feed to the calorifier. Otherwise it is preferable to have one accumulator fairly close to the pump to assist smoothing of flow.

 

[SimonD]

Thanks Vyv. I have an accumulator on the cold side next to the pump as you suggest. I'm not sure whether or not I have an NRV (if so, it's lurking somewhere inaccessible) but my PRV on the calorifier vents as soon as the water gets hot. I'm planning to replace it and that might be enough to cure the problem. However, I thought an expansion tank would do no harm (and probably a lot of good!)