Fitted new Tap (kitchen sink) - Now very little HW Pressue

[OscarFoxtrot]

What have I done wrong?

Fitted a new tap today to help out someone I've done a fair bit of work for before (I'm a joiner).

The old tap constantly dripped so they reckoned the disc was shot.

The cold water is mains fed and the hot is from a HW cylinder fed from a cold water tank above. The cylinder is an immersion heater.

There was no isolation for the HW other than the 22mm feed between the tank above and the cylinder. I turned the gate valve off and that restricted the flow and after a short while it stopped completely.

Fitted the new tap (had to remove the sink to get at it!), connected everything together and turned on. Cold pressure excellent, hot pressure little more than a dribble. The hot water flow at the bath and WHB is excellent and as good as it was before.

I thought there might have been an airlock so sent some cold water into the hot (via an old washing machine valve). It discharged via the expansion pipe into the storage tank but made no difference to the water pressure at the kitchen tap.

Have I done anything wrong? Is there something I've missed? Could the new tap be faulty somehow?

Any advice appreciated.

Cheers

 

[gremlin16]

If its a mono tap, is it suitable for gravity fed hot water.

 

[OscarFoxtrot]

Now that you mention it. No. Minimum operating pressure 0.5bar

I knew there was something I forgot to check

Thank you.

Lesson learned

 

[OscarFoxtrot]

Scrap that I checked the stats for the wrong tap.

Even worse minimum 1 bar required.

This header tank is only about 1m above the level of the sink.