Combi Vs Conventional Boiler with a tank

HappyMJ

How long does it take to fill a bath with a 24kW combi? About 10 minutes in my experience. A 10L/min water flow with an increase in water temperature by 35 degrees. Winter takes longer and summer shorter.

How long does it take to fill a bath with a 12kW conventional boiler and stored hot water? Around one minute. 30L/minute at 65 degrees plus 30L/minute of cold water mixed to make a bath of warm water in around a minute.

So that's why in my opinion a conventional boiler and stored hot water wins.

Next reason is the failure of the boiler. Boilers last for what 15 years but they might break down a few times in that period. I have an electric immersion heater so if the boiler doesn't work in an emergency I just turn the immersion on and I still get hot water until an engineer can visit on a non-emergency call out. I would not want a combi boiler to break on the Friday before christmas and have to call them out straight away and pay an emergency call out fee. I'll wait and save some money and still have hot water and heating (provided by electricity)

manda1205

Mister_G wrote: »

One point I would like to make is that in hard water areas combi boilers are more prone to furring up. I have experience of that and that is why I now have a conventional boiler.

Conventional boilers also appear to be of a simpler design and are less prone to going wrong.

This is just my own personal experience.

Which is exactly what we've had, and have now had a water softener fitted to combat it. Thats not to say we had no trouble with an electric water tank, that used to fur up just the same, and cause the thermostats and the whole tanks to be useless. In the 4 years we had an electric tank we had 2 thermostats and had to have a new tank. We also had problems with scale in the pipes and the hot used to trickle out. Which is why we had the water softener fitted, this totally solves the problem. And its brilliant.

HappyMJ - Our bath takes about 5mins to fill and I mean fill, we get a lovely full bath. Our old electric immersion used to take about 15mins to fill (although part to do with old furred up pipes) and we'd only get about 1/2 a bath if lucky before it went cold. It used to take a good 1hr to heat the tank again, so got used to having a half bath. This was a new tank as well. Im not worried about costs so much as the OP, but I really do prfer our combi to the immersion. I hated it.

Cardew

spinningsheep wrote: »

When we had a conventional water tank and an old non condensing boiler (which yours will be if it was installed since 2006, ---- we used to keep the water off as much as possible in summer and boil kettles for the dishes etc,

If it was installed post 2006 it will be a condensing boiler!

Why would you turn off a non-condensing boiler, and presumably keep on a condensing boiler?

spinningsheep

Sorry cardew you spotted my deliberate mistake (doh!) what I meant to say clearer was if the OP boiler was installed post 2006 it will be a condensing one, pre 2006 it won't.

Mister_G

manda1205 wrote: »

Which is exactly what we've had, and have now had a water softener fitted to combat it. Thats not to say we had no trouble with an electric water tank, that used to fur up just the same, and cause the thermostats and the whole tanks to be useless. In the 4 years we had an electric tank we had 2 thermostats and had to have a new tank. We also had problems with scale in the pipes and the hot used to trickle out. Which is why we had the water softener fitted, this totally solves the problem. And its brilliant.

HappyMJ - Our bath takes about 5mins to fill and I mean fill, we get a lovely full bath. Our old electric immersion used to take about 15mins to fill (although part to do with old furred up pipes) and we'd only get about 1/2 a bath if lucky before it went cold. It used to take a good 1hr to heat the tank again, so got used to having a half bath. This was a new tank as well. Im not worried about costs so much as the OP, but I really do prfer our combi to the immersion. I hated it.

We're on our third hot water cylinder in 30 years. Not bad for a hard water area!

manda1205

Mister_G wrote: »

We're on our third hot water cylinder in 30 years. Not bad for a hard water area!

Well either our landlord always got us cheap ones (if thats possible) or we do have harder water than you. From fitting our water softener when the plumber tested the water (with whatever kit came with the softener) it said it was the one below the highest that it read to. My mum and dad next door and also our other 2 neighbours all have the same problems with the electric immersion tanks so it wasnt just us. Then when we had our oil combi put in, the water furred up the heat exchanger within 18mnths. This is why we had softener put in as guarantee wont cover it again.

Milesbush

Hi I need to replace my boiler. The house is a 4 bed detached with two showers. One is a power shower thru pump. Also have a conventional bath. Currently I have conventional boiler about 10 years old and an immersion heater tank. British Gas and a couple of others have advised removing the immersion tank and replacing it all with a 31/32kw combi. Any advice please?

Cardew

Milesbush wrote: »

Hi I need to replace my boiler. The house is a 4 bed detached with two showers. One is a power shower thru pump. Also have a conventional bath. Currently I have conventional boiler about 10 years old and an immersion heater tank. British Gas and a couple of others have advised removing the immersion tank and replacing it all with a 31/32kw combi. Any advice please?

Welcome to the forum.

A combi will NOT provide sufficient hot water flow for even one pumped power shower.

If you look at the specification of even a large combi it will give the flow rate as xx litres/min raising the inlet water by yy degrees.

Some combis have a small internal hot water tank, but a pumped power shower will quickly use that reservoir.

Why do you need to replace a 10 year old boiler?

P.S.
Not for your benefit, but many people on MSE do not seem to know about a proper 'power shower' and confuse the term with an electric shower - which heats cold water.

alleycat`

Cardew wrote: »

Welcome to the forum.

A combi will NOT provide sufficient hot water flow for even one pumped power shower.

If you look at the specification of even a large combi it will give the flow rate as xx litres/min raising the inlet water by yy degrees.

Some combis have a small internal hot water tank, but a pumped power shower will quickly use that reservoir.

Why do you need to replace a 10 year old boiler?

Agree with everything you've said.
On the 10 year old boiler part.

I had to replace mine at 10 years of age (part of a new build estate) as it was an utter lemon.

I would say about 50% of the estate had theirs removed before i did mine as i had some DIY know how to keep mine going (+ i scavanged parts of those that were getting ripped out).

If i hadn't have had that knowledge (+ bits scavenged) it would have cost me (just in parts, over £1.5k).

I assume there was a design issue with it as every single person i spoke to that had theirs replaced needed at least 2 PCB's (1 household was on their 6th PCB in 9 years).

It gets very old, very quickly having to mess with the boiler 3 or 4 times a year.

I appreciate the ever increasing quest for efficiency but it seems to be done with the aim of reducing the life expectancy down to stupidly low levels.

stockportdave

What ever you chose I suggest that price is not always a good guide to quality. This is my experience
Regarding worcester bosch Combi Bolier
Mine developed a leak in the expansion chamber during the latter part of the 2 year warranty. I thought I had a leaky rad so I waited until the leak was evident. When I realised it was the expansion tank I claimed - but! as it was 1 month out of warranty they would not fix it. I know I can get them on the Sale of Goods act but its less effort to just replace the tank.
My point is that Worcester Bosch quality may be on the slide (no one stays at the top forever) and their customer service is not what one would expect.