Loss of Hot Water Pressure to Shower

Ecknumber1 said:

Looking for any ideas to help.

I've a Heatrae Sadia Hot Water tank, heated through Oil fired boiler (working fine).

A week ago I reset the air gap as I was having dripping from the pressure relief valve. Since then I've lost a lot of pressure from the hot water feed to my shower. The rest of the hot water taps have good pressure. I've checked the pressure from a hot water feed and it is sitting at 3 bar so I don't think its the pressure reducing valve.

The shower is a recessed shower/bath mixer, so I've taken the thermostatic mixer out its in good order. When I isolated the hot water intake its a very poor flow into the mixer.

I've tried all the usual ways of getting rid of an air lock such as cutting the mains flow and opening all taps and then bringing them all back gradually, blocking the end of the mixer and forcing the cold back up it and even tried plunging water back along the hot feed to the shower but nothing has improved the flow.

Getting frustrated now as the shower used to have great pressure.

Without pulling all the tiles off the wall to check the piping, can anyone offer any other solutions that I could try?

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Best said:

Just reread your post and I see you said you checked feed to shower and it was poor flow. Maybe a valve in-line to shower valve somewhere and blocked?

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John.g said:

Its strange that the problem started when you reset the air gap, maybe worth re doing it even though it shouldn't be the problem as you are getting 3 bar at a hot tap, can/have you checked this pressure with another hot tap opened somewhere?

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Ecknumber1 said:

I've just done the process again and no improvement.

I've also checked the pressure and still at 3 bar, it reduces a little when I turn on the bathroom sink hot tap, but when I run the bath or shower there's no change to the pressure.

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John.g said:

I take it that the bathroom sink hot tap flow is OK?.
Where are the hot bath and shower hot teed into the hot supply in relation to the sink hot tap T.
Is the bath cold tap flow OK and are the bath hot&cold taps separate taps.

Hope not, but is it possible that the baffle is breaking up and when you drained down the cylinder to the bottom of the dip tube that bits of it havn't caused a blockage to the bath/shower.

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