Replacing boiler with combi boiler, water pump still needed?

14 Jan 2021
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United Kingdom
Hi all,

I currently have a standard boiler that has been in my property since the beginning of time (or so I'm told). I'm considering replacing it because every year, during ScottishGas' routine service visit, the same "oh, it will be difficult to source parts" speech is told.
One of their guys had come in to do a survey and give me a quote for a new boiler. I was given the option between replacing like-for-like or getting a combi boiler and they'd remove the hot water cylinder and the cold water tank that is in the loft.

I am leaning towards the combi option as it would give me some room inside that I can definitely use for storage. However, I'm worried about one thing. I currently have a water pump so that the hot water (and cold!!) actually have pressure in the upstairs bathrooms. Their guy has claimed that the water pump would no longer be needed and it would be removed. Is there a way I can confirm this before I sign off on this?

My other half is delighted that we don't need to hear the water pump firing off but I'd rather have the noise than having to shower using a dribble of warm water :)

Is there a way I can check before I sign off on it?
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If your water mains pressure is good ,you won't need a pump. Combis hot water is under mains pressure ,and your cold water to taps would be too, once the loft tank is removed.
How good is flow and pressure from the kitchen cold tap? If you're getting 20 litres per minute at 2 bar dynamic then a combi (or unvented cylinder- you mentioned bathrooms plural, most combis won't manage 2 showers simultaneously) will work well. If mains pressure is poor then you may be better with a new heat-only boiler and keeping your shower pump, water tanks and cylinder.
EDIT The big national companies (BG I'm looking at you) will push combis at you relentlessly, they may not even make you aware other options are available)
Thank you for the answers so far!

Cold water pressure from the kitchen sink is perfectly fine! I'm not sure if it does 20L/min but it does have a good enough pressure.

We don't use two showers at the same time because even right now one shower affects the other. We've learnt to survive with 1 single person using a shower, even though there are two in the house :) (we're three in the house, btw... not exactly a huge family)

Would central heating be affected with the combi boiler installation? Would that have an effect on hot water for showers?
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Combi boiler gives priority to domestic hot water ,so when hot tap/ shower/ bath is running the central heating is starved . As the time spent running hot water is very little ,most people wouldn't even notice .

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