Unvented Cylinder Set Up As Vented

[Edward Cox]

Hi everyone,

I'm looking for some advice please...

We had a heat pump installed about 10 years ago and with it a Joule twin tank setup. The bottom one is the buffer tank and the top one is an unvented hot water cylinder. However, the hot water cylinder was set up vented. This was working OK until a pump was fitted. Now, particularly after the immersion has been run on a legionella cycle, the hot water pump feeding the hot taps in the house is sucking in lots of air.

I think this may be because the vent pipe is not allowing air out of the cylinder due to it not being top entry and with the added problem of going down before going along and back up again to the loft.

Is there a way to fix the problem?

Thanks,
Edward

 

[The Happy Builder]

Pictures of the hot water cylinder connections would shed more light on the issues than a diagram.

 

[Edward Cox]

Good idea, thanks. First image is the overall setup. Second one shows the outlet for the pump feeding the hot taps in the house. The third and fourth show the shower pump and vent outlets.

 

[The Happy Builder]

Is that diagram accurate with the expansion pipe dipping right down before going back up on the the original expansion and vent pipe?

 

[Edward Cox]

Yes, it's the one in the fourth photo at the back of the cupboard. Left of centre.

 

[Jimbo]

If you use a whole tank of hot water every day, the legionnaires cycle is probably unnecessary.

 

[Kiaora oap]

hi
the hot distribution pipe from the cylinder must go either level or up hill !
this will allow air to vent, other wise lots or air will be trapped

ideally turn the elbow from pointing down to pointing up. and then a tee off to hot supply and the vertical pipe to vent over the f&e tank

good luck