new boiler?

mommymagpie169

Our water pressure is rubbish from storage tank and have a 28 year old boiler system.
Thinking of replacing with a new combi mainly because of water pressure.
Thoughts?
Plus is there a way to pay for one with a credit card? I've a goof credit rating and though a 0% card would be best way to finance it but do independent plumbers etc accept credit cards?!
Plus I'm thinking there would be at least some savings going from such a new boiler to a new efficient one?
Thanks in advance

Robin9

Whether or not you can pay by CC depends on the supplier - don't assume you can - ask.

Many tradesmen prefer payment direct to bank.

mommymagpie169

Hmm, need to look into balance transfer type things then - some of the deals means it looks like I could finance the new boiler for around £55 a month based on the quotes I've been given re cost etc, which would be far preferable to paying it upfront!

CashStrapped

Before you contemplate getting a combi, there are a number of things you need to check first.

If you have a traditional gravity system i.e one with cold storage tanks in the loft. Then there may be certain things that can be changed, at relativity little cost that can dramatically improve water flow.

Firstly, flow and pressure are two different things.

The pressure is how much "push" you have in your system. You can have mains pressure (sometimes in a gravity system the cold is on a separate mains pressure). If you have a good mains pressure, your water has a lot of force coming out of the taps.

In a gravity based system, the pressure is determined by how high above your head the tanks are. So the pressure will always be a lot lower.

However, low pressure does not always mean poor flow out of the taps.

Flow is how much water comes through the taps. Normally this is measured in litres/min.

- So, in a gravity system, you can have low pressure, but high flow.

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In your case, if you are complaining about how long it takes to fill a bath, this may be more to do with the flow rather than the pressure.

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For example, many people do not realise that the majority of modern taps are not suitable for a low pressure system.

If you have taps that are quarter turn, half turn or waterfall taps, or anything like that, a gravity system does not have the pressure required to make them work properly. You will only get a dribble out of them. This is because the ceramic washers have tiny holes which water (with enough pressure) is designed to be forced through. These taps are only designed for high pressure systems.

What you need are taps designed for a low pressure system. These normally have rubber washers and are the traditional multi-turn type taps. These taps do not restrict the flow of water as much. So in a system with low pressure, not much force (pressure) is required to allow a lot of water to flow through it.

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Basically, in a low pressure system, you are trying to get your hot water supply to the taps with as little restrictions as possible.

The pipework to the hot taps (for the bath specifically) should be the larger 22mm pipework. There should be no isolation valves on them. There should certainly be no flexible pipe (flexible pipe restricts flow a huge amount), and as per above, the correct taps.

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As an example, I had a property with a gravity system, and as you are finding out, terrible flow.

The bath filled at 4 l/min. Terrible. However, it had the wrong taps, isolation valves and a small section of 15mm pipework.

After changing to the appropriate taps and fixing the other things, the bath filled at 16 l/m ! More flow than most modern combis can supply.

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If you do want to go down the combi route. There are a few things you need to be aware of.

First, having good pressure is not a given. It depends on your mains supply in your street, this should be checked as part of any assessment. Secondly, running any two outlets that use water in a house with a combi often results in a dribble. Combis are less reliable, so you have to ensure they are well serviced.

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As with anything, some of this comes down to how good your installer is. But, having a gravity system myself, I have never been in a property with a combi that is as reliable, and has such a good flow and supply of hot water.

All the combis I have ever experiences often cannot keep up with demand and the water runs cold after a bit, or it ends up being a dribble if someone else uses a tap.

Again, I may just have been unfortunate enough to experience poor installations of combi boilers.

But, depending on how you live. Your water demands and what you can afford, it may not solve your frustrations.

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If having a modern, more efficient new boiler is something you want then a combi is not the only solution. The cheaper option is to replace it with a modern condensing heat only boiler. This can be retrofitted into your existing system with a few minor changes.

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So, food for thought.

mommymagpie169

Many thanks for you answer cashstrapped, plenty to think about! I'm not averse to having a hot water tank, i've a large airing cupboard that has the existing tank and boiler in it already, and I quite like how cosy the cupboard is and how quickly it dries laundry!
The shower I've just installed is designed to work from the lowest pressure rating - 0.1? i think. The cold water flow is pretty good, its the hot that's the problem - really slow from any of the taps aswell as the shower.
We're in a bungalow so so their is never going to be huge amount of gravity i wouldn't have thought? The cold tank is in the loft.
Hmm, think I need to get a knowledgeable plumber round who doesn't have a huge interest in selling me a combi boiler!

CashStrapped

As I said, it is all about your needs.

I was just highlighting a cost saving alternative, which may "fix" your issue.

I always try to give a variety of options.

It sounds like you have mains fed cold, and gravity hot, as I suspected.

So, if you do not want to spend a lot of money on a new system, checking the things I mentioned may improve things a lot.

For example, on the shower, ensuring that the shower hose has an 11mm bore (diameter of internal tube). Having it at the shortest length possible also helps. Those multi-turn taps are a must though. Flexi-hoses multi-turn taps, isolator valves on the hot pipes...all restrict flow a huge amount.

Also remember, just because items say they work with low pressure, does not mean they will be any good. Hence why you must avoid all quarter turn, half turn taps.

Even silly things like the red gateway taps near the hot water tank not being open all the way can be a cause of poor flow.

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Combi boilers are not bad per say. It just depends on, as with everything, how well it is installed. Ensuring your incoming supply is good enough to work well with a combi is one thing the plumber should check.

You just need to be aware of the pros and cons of each system. Although a combi is more suited to as small bungalow than it is a larger property. So after you have looked at all the options. You may find a combi is indeed the best option.

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My post was mainly to highlight that, before you go to the expense and upheaval of a costly whole new system, there maybe other options that fix the issues you have for a lot less. If the current system is in otherwise perfect working order, is there any point in replacing it.

This is a really good guide showing the things to check if your flow from the hot taps is poor.

http://www.forest.plumbing/why-your-water-pressure-might-be-low-part-2/