Will my boiler explode if I turn on my shower?

[prepperpig]

We have just had a new biomass boiler installed and so we now have an unvented heating system which replaces our old vented system. I have just realised that the heating engineers haven't done anything about the shower pumps. Should these have been taken off? Would it be dangerous to turn on the shower?

[PigletJohn]

Have you changed the hot water cylinder?
What colour is it?

Is there a cold water tank in the loft? What size? Is it still used?

When you put your thumb over the hot tap in the bathroom, can you stop the flow? And the cold one?

[prepperpig]

Erm…I will check. I know there is still a hot water cylinder in the airing cupboard and still a cold water tank in the loft. Does that mean the heating is unvented but the water is still a vented system?

Ive called the heating engineers who have installed the boiler but we will use the immersion heater for now and have baths just in case...

[whatsthatcomingoverthehill]

Well the taps, shower etc are all vented cos the water comes out!

[whatsthatcomingoverthehill]

I would have thought that the hot water in general acts like it did before, otherwise they would have told you. So I reckon you'll be safe.

[PigletJohn]

"Does that mean the heating is unvented but the water is still a vented system?"

very likely yes, but I need to know the colour of your hot water cylinder and what your thumb does.

[prepperpig]

The tank in the airing cupboard is copper coloured. Presumably you mean this one rather than the central heating tank which is a ginormous 3000 litre accumulator tank? If I put my finger over the tap it spurts.

[PigletJohn]

a copper coloured cylinder is not unvented so it is not pressurised. So it is OK to use a shower pump with the water from this cylinder. I am surprised that your thumb will not hold the flow though. Does it spurt from both hot and cold taps?

Did they call the CH tank a Thermal Store? Is it hot now, even though the CH is off? Are you sure it is 3,000 litre not 300 litre? Is it white?

Does the copper-coloured cylinder get heated by the boiler, or just by the immersion heater?

[prepperpig]

Phew that's good. No the water spurts when switched to hot or cold but we do have very good water pressure here.

The central heating tank is an akvaterm accumulator tank. It's not hot to touch but the temperature shows over 80 degrees. Its a massive 3000 litre tank which only needs firing up once every few days (which is good because this biomass boiler looks set to be high effort!)

Thanks for the help

[prepperpig]

Missed a bit, the cylinder in the airing cupboard (copper one) gets heated by the boiler.

[PigletJohn]

"No the water spurts when switched to hot or cold but we do have very good water pressure here."

That is puzzling because if the bathroom taps are fed from the loft tank, the pressure of the watermains would be immaterial.

Your thumb should be able to stop the flow from the loft tank. If the pressure in the bathroom is too high to stop with your thumb, why do you need shower pumps?

I have 1bar of pressure from my loft tank in the downstairs shower (10m+ of head) and can stop it with my thumb.

I don't know how your system works.

[prepperpig]

Perhaps I just have wimpy thumbs