Replacement Gas boiler - which option

[ACS]

Our very old gas boiler has expired and due to its age (20 years+) will have to be replaced.

One company has recommended that we get rid of our copper tank (in good condition, well insulated) and install a wall mounting condensing combi boiler (Greenstar 24i junior).

However another company has recommended keeping the tank and installing a direct replacement for our current free standing boiler again a condensing combi unit (Greenstar RI 15w)

The house is a 3 bed semi - det medium sized type property.

Can anyone help me with some advice, keep the tank and if we do to what benefit?

Many tanks (ouch)

Andy

 

[gavintc]

Many tanks (ouch)

That is dreadful.

I have made the change twice in separate houses and in each I have fitted a condensing boiler as I was advised that this was more efficient. Certainly, in one house, the loss of the tank provided more storage space. I will be interested to hear what some of the experts on here recommend.

 

[ELL]

I don't know a lot about boilers but I work for a bathroom company and we had a training thing this week. We started talking about water pressure and that got us on the the subject of boilers. We were told that a combi boiler is probably best for smaller 1-3 bed places with 2-3 people. A tank for bigger places.

A combi can struggle if you have a few hot water taps on at the same time as it heats the water as it goes through but it doesn't have to heat up a big tank full of water just so you can fill the sink to wash up a couple of bits.

The combi boiler we have at home means we save a lot of room as don't need the hot water tank in an airing cupboard and no need for the cold tank in the loft.

 

[Spinney]

As I understand it, for the option where you keep the tank the boiler won't be a combi boiler. (ALL boilers these days have to be condensing boilers, and you will probably find that the boiler people also fit thermostatic radiator valves while they are at it, unless you already have them).

If you are considering ever installing solar water heating, I think you have to have a tank for that. Otherwise, it depends on the flow rate you want for hot water. Aren't the combi ones more expensive to buy, as well?

I had to replace my boiler earlier this year, and went for a straight replacment. Partly because it would have taken them an extra day or two to faff around removing the tank and all the stuff in the loft, and putting in an extra gas supply pipe (according to them, a combi boiler would have to have been put where the hot tank currently is, so a pipe to supply gas to the upstairs would have been needed). Partly because it would have cost more. I live on my own most of the time, and often don't have the heating on at all in the summer, not even for hot water (electric shower, and just boil a kettle for washing up), so the 'heating a tankful of water just to wash up' problem doesn't usually apply.

 

[slowmotion]

Andy, here is an article that gives some simple advice...

http://refurbn16.com/2010/01/09/boilers-pt-1-regular-vs-combi/

What a lot of people do not appreciate about combis is that although you will get hot water at mains pressure, the flow rate will be limited by the combi's power rating. For example, a 28kW combi can only produce about 12 litres of hot water per minute, enough for a decent shower but not much else.

Another thing is that the summertime efficiency of combis (when they are just heating hot water) can be really quite dreadful, sometimes as low as 45%, according to the results of one field trial that I can't find right now.

We had our boiler replaced two weeks ago with a standard condensing boiler. Worcester Bosch and Vaillant are highly regarded manufacturers.

Good luck

 

[brokenbetty]

Everywhere I have lived since leaving home has had a combi. I like them but agree about the disappointing water flow rate. All the combis I have inherited couldn't heat water at full flow, so if the hot tap/shower was on full flow it would only be lukewarm.

When we replaced the boiler in this house we stuck with a combi but overspecc'd it to make sure we got properly hot water on full flow, and now it's the best of both worlds - unlimited hot water at mains pressure. The only problem is whenever we go away now the shower is a letdown compared to home

(2 bed, 1 bath small terrace, boiler is a Vaillant ecotec plus 831)

 

[Over The Hill]

With the combi option you lose the copper tank plus the two header tanks in the loft along with lots of now unnecessary pipe.
Plus you can have a nice shower with mains pressure hot water.

With the traditional you keep the tanks, have uneven water pressure but have the option of heating the hot water with the immersion heater in the summer.

I have replaced two boilers in the last two years and opted for combi in one and traditonal in other.

Combi was in a rental house and means I can do away with the electric shower in the house and I may put a bedroom in the loft which is now empty.

Traditonal at home as the boiler is 45 feet away from the kitchen sink and 30 feet away from the bathroom and the lag in warm up would be too long. My house is long and thin with the boiler at one end.

 

[asterix]

Got a combi/condensing boiler put in under scrappage earlier this year.

The gas bill went through the floor. Flow rate is fine; the boiler is a Weissmann with some rather complex wireless digital control and cr+p instruction book. The c/heating is never off, you just have 3 temperature settings i.e. comfort/daytime/frost protection and choose their times of day. Customer service isn't great.

 

[dellzeqq]

two questions.

a) How far is the water level in the tank above the highest shower head?

b) How reliable is your mains water pressure? (We could go postcode about this, but that would be prying).

 

[buggi]

What do you mean by expired??? Have you been told this or has it broken or been condemned??? I work for a major gas company. That said, I admit I don't know much about boilers but I would you get an independent opinion, rather than the opinion of someone from your gas supplier who i think will do/say anything to make a sale. i don't think 20 years is old for a boiler so be careful you're not being ripped off and Combi boilers aren't always that powerful.

My mum was told by British Gas that their boiler was obsolete and they could no longer get parts for it, so recommended she replaced it. They charged my mum £1500 for a new boiler which would be a wall boiler so would free up the space where the standing boiler would be.

Besides the fact that an independent adviser then told her after that it was bollocks about it being obsolete and he would have no problem getting parts for the old one, they have had all of these problems with the new one:

1. it keeps breaking down.
2. it didn't free up the floor space where the standing one was. They had to leave all the pipework there because for some technical reason it couldn't be taken out. so my dad had to build a cupboard there to hide it.
3. They tried to reroute the pipe up the wall and across the ceiling but luckily my mom came home from work early and had a mental. Then after some arguments with the workmen and her threatening to halt the work and stop the cheques, they decided it would be possible to bury the pipework in the wall after all.
4. They went on the monthly payment scheme where they promise to come out and fix problems in 24 hours. After 3 years of having it regularly serviced it went kapoot. they came out and said a plate was corroded on the back of the boiler and condemned it. They then said that although they had the plate in stock, they had no-one to fit it for 2 weeks, so no hot water or heating for two weeks despite them complaining everyday. When a new gas fitter came out to finally fit the plate he told my mum and dad there was NEVER a plate on there (this had been missed during 3 years of servicing!) and that basically carbon monoxide had been leaking into the house for 3 years. Also the outlet pipe was in the wrong place because we basically walk out the back door into the fumes!

My mum and dad never had problems with the old boiler and it was over 25 years old. British Gas lied to them that their boiler was obsolete to get their business and they've been stuck with a problematic boiler ever since. Just because they don't make them anymore, or there are new styles, doesn't mean the parts are unavailable.

Basically, if your boiler isn't broken or hasn't been condemned and you have it serviced regularly, then there is no reason why you need to change it at this time. If you've got any more concerns, get some independent people (registered "gas safe") to come in an assess it.

If they have condemned it and say they can't get parts, phone an independent "gas safe" fitter first to see what he says.

 

[MacB]

We went for a combi over a system boiler against the perceived wisdom of various quotes etc, but we did overspec the combi to ensure decent HW flow rates, we also have high mains pressure. Either system is the same for central heating it's only the HW aspect that varies. The reasons we were given for needing a system boiler were so that we could run more than one shower or bath at the same time. Our showers are electric anyway so it didn't seem sensible and I prefer HW on demand rather than relying on a tank. With 5 of us the chances of the tank not running out at inopportune moments is slight. The boiler we went for was in the Worcester Greenstar range, can't remember model off hand.

On the downside you have to watch your coldwater feeds as they all go from tank to mains supplied. We've had to sort out two of the toilets and a couple of taps that didn't cope with the increased pressure.

Our bills have dropped since installation but it was an old system before so I don't know how much, if any, of that is attributable to combi v system.

 

[Globalti]

Go on the plumbing section of DIYnot.com and see how many people are having problems with combis. I wouldn't touch one with a barge pole, I have lived in two houses with combis and both were a nightmare. Combis are too unstable and need constant adjustments.

We recently ditched our old boiler and bought a new condensing boiler, our gas bills are down by about 40%. That's good enough for us.

If the boiler is old you'd do better to replace the cylinder at the same time with a modern one with a quicker reheat time, condensing boilers work better with these anyway.

 

[Mr Celine]

It's quite time consuming to calculate the proper size of a traditional non-combi boiler and errors are expensive. Even the smallest combi has a heat output greatly in excess of what you need to heat a 5 bedroom house, so the installer doesn't need to bother with these calculations. That is often the reason why installers recommend them.

 

[slowmotion]

Another thing is that the summertime efficiency of combis (when they are just heating hot water) can be really quite dreadful, sometimes as low as 45%, according to the results of one field trial that I can't find right now.

Sorry, I got that wrong. I think the summertime efficiency could be a lot higher. Apologies all round.

 

[asterix]

Phew! that did puzzle me..

We got a quote from British Gas but only for a laugh. Our one-man-band installer did a superb job and the main reason we scrapped the boiler was because our system was a direct cylinder and fantastically unreliable. It was lovely to see all those unnecessary pipes and tanks sent for scrap.

WRT to pressure, I like the French system where the hot water is fed at mains pressure. No mains gas unfortunately so it's all electric.