Airlock in electric shower

[HumanAstronomer3194]

I'm trying to install an Mira Elite SE electric shower that is gravity fed but the feed has an airlock which I'm not sure how to fix.

I've no way to isolate the feed from the tank so I've shut off the mains and emptied the header tank. I did have an airlock on the cold tap too but once I opened a cold tap downstairs the upstairs cold taps started to work again.

I'm following the instructions as per https://www.plumbworld.co.uk/docume...d-electric-shower-installation-user-guide.pdf

But as you can see from the below video once I push up the rod water does flow at the very stand but then stops.

20250101_ShowerFilter.mp4

• HumanAstronomer3194
• Wednesday at 8:31 PM

I did try and use a dry vacuum but I know I'm playing with fire if I continue to do that.

Is my only option to hold in the rod and get a wet vacuum to try and pull out the air in the pipe?

I haven't tried this step yet but I don't think it would make much of a different

 

[andy_nufc]

I'm not an expert, but isn't an electric shower like this designed to operate with mains pressure cold water, not cold water fed from a header tank? There won't be anywhere near enough flow. Edit: my mistake, on looking at the instructions in does appear to intend to be pumped from a header tank, yet at the same time electrically heated.

 

[HumanAstronomer3194]

I'm not an expert, but isn't an electric shower like this designed to operate with mains pressure cold water, not cold water fed from a header tank? There won't be anywhere near enough flow.

I'm actually replacing it for an old one that needed replacing and this shower is designed to be used with a gravity system.

 

[Stuckinarut]

I’m unable to play the video, but how do you know there’s an air lock? Is the cold water storage cistern filling back up? If you’ve completed step 4, then I would try the next steps including 7.

 

[HumanAstronomer3194]

I undid the connection and I just get this dribble even though the tank is full and all other cold water taps are now working too.

 

[Stuckinarut]

I undid the connection and I just get this dribble even though the tank is full and all other cold water taps are now working too.
View attachment 367667

Are you able to back feed that with some mains water and reconnect? Or perhaps extend and suck on the pipework to get it moving?

 

[HumanAstronomer3194]

I was messing around with the hot and cold taps at the sink and noticed the water stopped for a bit on the shower feed and then started to flow a bit more so I opened both shower taps (not to be confused with the electric shower feed) to remove some pressure while I redid the nut and now when I press the rod on the shower I get consistent pressure.

The only difference I did was open the hot tap but I'm not sure why that would have resolved the issue? As this feed should come from the tank but I don't know that for sure as I lose sight of the pipe behind the wall.

 

[HERTS P&D]

Got a wet vac?

Andy

 

[HumanAstronomer3194]

Got a wet vac?

Andy

Don't have a wet vac was looking to get one from ScrewFix tomorrow but thankfully messing around with the hot tap managed to remove the airlock and I've no installed the shower.

Thanks all for your help.