Mixer Shower - no pressure

[jamekel]

We currently have a condenser boiler and an imersion heater with a gravity system. We have just bought a mixer shower but the hot water takes a long time to come through and there is very little pressure. We were advised that we have 2 bar of pressure which we were told would have been suitable for the mixer shower which appears it isn't? What I need to know is whether we need to but a pressurised motor valve for the tank or do we need to buy a combi boiler? We have a 2 bedroom house with one main bathroom which is now just a walk in shower and an en-suite.

We have been told various things that the current system we have is fine and would work with a motor, But means that the imersion heater would need to be on all of the time or to have a condenser combi boiler.

The en-suite runs off an electrical shower - pressure is fine and water it hot and heats up quickly.

CAN ANYONE ADVISE?

Thanks

 

[linkyplumb]

The pressure of 2 bar. is for for the cold main coming in I would imagine.
As you have a gravity system, for you to get that on the hot you would need the cwsc to be 20 metres above the shower head.

You do not need a combi boiler. Either a dedicated shower pump for that specific shower, opr a hot water booster pump, that would do your whole hot water system.
Does your boiler only do the central heating then?

 

[TicklyT]

Your incoming mains water pressure has no relationship to the pressure available from your gravity hot water system. the two systems are isolated by the cold water storage tank.

Gravity systems work well when all the components are suitable for the low pressures the system operates at, typically 0.2 - 0.5 Bar.

Many mixer valves are only suitable for water pressures above 1 Bar. They are intended for use with combi boilers and unvented hot water systems. Installing one of these on a gravity system usually leads to disappointment.

Mixing a low pressure gravity hot feed with a high pressure mains cold feed can lead to another hat full of headaches too.

Adding a shower pump can boost the water pressure to the mixer without need for a replacement boiler or any changes to your water heating policy.

 

[longdogs]

You could install an electric shower which would give you hot water independently of your immersion heater or an Aqualisa type shower where the controls/pump are in the loft and doesn't require much pipe work or damge to your tiles.

As previously mentioned, a pump would probably be the cheapest option and would supply all the hot water in your house but you would still need to use the immersion heater. If you do, buy a good one so that it's quiet.