Storage/immersion and combi help

CrimeWave

I have a storage/immersion tank thingy downstairs and a condensing combi boiler too. It's a newly renovated house, no idea why I need both, just wondering if someone can help. I have turned off the electric to the storage as we use very very little hot water so all I get from the hot water tap is cold water...surprise surprise. Firstly is that ok? Next, can I get hot water 'direct' from the combi by-passing the storage straight to taps? On the box on the wall that controls the CH times there are hot water buttons to turn it on but cant seem to get hot water from the taps although I hear the boiler working its little socks off. Now I am partial to a shower every few weeks :rotfl: so my tap mixer jobbie is a bit useless with only cold water. Cold water mains pressure is excellent and rcd box is directly under bathroom so is putting in an electric shower easy as pie ? Boiler is a greenstar 24i The econo button doesn't work on boiler too (which I guess is hot water only when I want it and need to run it for a few seconds). My little boiler room is so complicated with lots of pipes and switches and pressure bottles and I just dont have a clue, all help greatly appreciated.

m_13

Mmm. Complicated. It sounds like there might be more to your 'storage/immersion tank thingy' than meets the eye. Are there any labels on it: brand names, product codes etc?

Putting in an electric shower may be 'as easy as pie' but electrics in a bathroom can only be completed by somebody who is Part P qualified. Regs change again on 1st July and bathrooms are 'special locations' so you need to have somebody who is not only competent but aware of the new requirements. Bizarrely the new regs say that under some circumstances you can have a socket in a bathroom - we've just had ours removed!

Your boiler:

The Worcester Greenstar 24i junior boiler a condensing combi boiler is suitable for a small/medium sized, 1 bath flat, apartment or house.

• It has a wall mounting frame with pipes behind leaving no exposed pipework.
• The boiler is environmentally friendly with low NOx and CO2 emissions.
• For convenience it has a keep hot facility which keeps the primary water within the heat cell hot. This will ensure that hot water is available instantly on opening the hot water tap.
• If the eco mode is engaged the keep hot facility is de energised and hot water will be heated from cold as required. Whilst this creates a slight delay it does improve the energy efficiency of the system.
• When the central heating is required the boiler will initially fire at a minimum output gradually increasing its heat generation to meet the requirement. Electronics within the boiler continually monitor this to match power output to domestic requirements.

So the Eco mode button stops the key hot facility and makes the boiler heat the water every time the hot tap is turned on.

Post more about your storage immersion tank thingy and I'll try to help further.

CrimeWave

Right I've had another look and took some piccies. The storage tank is Manco branded, the 2 pressure vessels begin with z. I had a little mess and tried the hot water tap button on the little box and all the CH came on even though the thermostat was on zero :eek: . There is a box and pipe with a manual/auto switch that goes from the boiler to the bottom of the storage heater. The pipe got hot. There is also another manual/auto box where the pipes went to upstairs and downstairs. The white pressure vessel pressure went up when the hot water button was on that goes to the boiler. There are 2 red valves near the white prssure bottle and top of the storage heater one with 3 bar and another with 7 bar written on. I opened it and the white pressure vessel pressure went down then equalised again when returned to normal.
From the looks of it i dont think I can get hot water direct from the boiler only from storage, but I could be wrong.

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EliteHeat

It's not a combination boiler.

It is a system boiler with an additional remote expansion vessel attached. In addition you have an unvented hot water cylinder.

It's not a complicated setup, it looks quite good to me.

CrimeWave

Thanks for that fella, but what does it actually mean and how does it affect my original question? Is that set up any good? eg efficiency?

m_13

System Boiler:

[SIZE=-1]Like conventional boilers, a system boiler can provide central heating and hot water from a cylinder if required. The key difference with a system boiler is that all the major components are built in to the boiler. For example the pump, normally installed remote from the boiler, in built in; so is the expansion vessel, which replaces the feed/expansion tank often installed in the loft. The safety valve, the automatic air vent and even the programmer are also included. With these components built in installation time is reduced significantly, fewer materials are required, costs are reduced and servicing is simplified. The added bonus of a "dry loft" removes the worry of any leak or frost damage to tanks and pipe work[/SIZE][SIZE=-1]. [/SIZE]

Unvented Hot Water:

In an unvented system, incoming cold mains water typically enters a pressure vessel (for example: a Megaflo made by Heatrae Sadia, or a 'Vantage' made by Vaillant - there are of course others) where it is heated either Directly by means of electrical heater/s, or Indirectly by means of a primary heat exchanger within the vessel being supplied by your central heating boiler. The hot water stored within the vessel is forced out by the incoming cold water when you open a tap hence - Mains Pressure Hot Water.

So you have a system boiler which heats the water for the heating and supplies a primary heat exchanger inside the unvented hot water pressure vessel. Mains pressure hot water usually gives you a much larger choice of taps and showers as the pressure for the hot and cold is equal. However, if your cold pressure is rubbish so will your hot pressure. If your cold pressure is good then your hot pressure will be good and you will be able to simply have a thermostatic mixer valve shower (rather than one that heats) and still get a power shower type performance (but think of the environment!).