Combi boiler right for us?

[MugabesDeadCat]

Hi, we live in a 2 bedroom, one bathroom house, and currently have a 25 year or so old back boiler. Thinking maybe it isn't going to last much longer, so as a preventative measure I'm considering replacing it with a combi.

Is a combi the right choice though? We currently have no shower, so if I got a combi I would get one fitted to run off that. Some people say I should stick with the back boiler, while others say switch to a combi. I'm a touch confused to be honest.

If we did switch to a combi, what sort of work should also be carried out? i.e does powerflushing have to be carried out? Also, if a combi is ok for us, what sort of boiler would £800 or so get you? Obviously installation costs would have to go on top of that, which I'm hoping would costs no more than £2200 on top of the boiler cost.

Thanks

 

[muggles]

If you only have one bathroom and two bedrooms a combi should be fine, your hot water demand isn't going to be huge. Powerflushing isn't generally a requirement of installation, a chemical system flush is usually sufficient, although the cleaner the system the better before you fit a new boiler so if you can afford a powerflush then go for it. A chemical flush would be much cheaper but could be less effective.

You'll get 20 different answers on which boiler to look at on here, installers tend to have their favourites and ones they are familiar with, and can sometimes offer longer warranties if they're approved by the manufacturer. We use Vaillant boilers, Intergas are also worth a good look, their latest combi is well-designed and so far seems to be very reliable, I'm seriously considering using an Intergas combi to replace my grandmother's ageing back boiler system.

 

[muggles]

nuts, double post

 

[Rob]

Check you flow rate of the mains water.

This is what determines if you should get a combi and if so what size.

Your back boiler was sized to match your radiators. Combi boilers are sized to match the water flow rate. Its a litres per min figure so get a bucket and stop watch.

Even the smallest combis should give a decent shower (assuming you've got the flow rate!!) but they'll struggle with baths so you size accordingly.

 

[bengasman]

A good combi will be fine.
More important than the exact choice of boiler ( as long as you stay away from notoriously bad makes like ravenheat, ideal, halstead etc) is the quality of the installer.
Never trust an installer that "recommends" one of the above brands. Vaillant, although not a bad boiler in itself, has a terrible reputation as a company when it comes to customer service/aftersales.

Finally, if you take the plunge, do it between June and September; traditionally the least busy time of year, so minimum chance of a rush job.

As for my own choice, I changed my preference from WB CDI to Viessmann.

 

[xr4x4]

a combi boiler will always limit you to not having a decent power shower.

i would prefer a system boiler.

i guess you currently have a hot water tank heated by the back boiler?

 

[MugabesDeadCat]

a combi boiler will always limit you to not having a decent power shower.

i would prefer a system boiler.

i guess you currently have a hot water tank heated by the back boiler?

Yes, we have a tank in the loft. What is the difference between a combi and a system boiler?

 

[xr4x4]

a combi boiler will always limit you to not having a decent power shower.

i would prefer a system boiler.

i guess you currently have a hot water tank heated by the back boiler?

Yes, we have a tank in the loft. What is the difference between a combi and a system boiler?

a combi heats the hot water on demand, theres no storage. so if you had a hot water tank, that would get removed. when you turn on the hot tap, the boiler fires up and heats the water directly.

a system boiler heats a hot water tank.

you can fit a power shower to a system boiler with a hot water cylinder but not a combi.

edit
do you have a hot water cylinder in the airing cupboard?

 

[MugabesDeadCat]

a combi boiler will always limit you to not having a decent power shower.

i would prefer a system boiler.

i guess you currently have a hot water tank heated by the back boiler?

Yes, we have a tank in the loft. What is the difference between a combi and a system boiler?

a combi heats the hot water on demand, theres no storage. so if you had a hot water tank, that would get removed. when you turn on the hot tap, the boiler fires up and heats the water directly.

a system boiler heats a hot water tank.

you can fit a power shower to a system boiler with a hot water cylinder but not a combi.

edit
do you have a hot water cylinder in the airing cupboard?

No, just a tank in the loft

 

[MugabesDeadCat]

Not very scientific but using a jug on the cold bath tap we get 30 litres of water per minute I think. What does that translate to in terms of fitting a combi? Think we get 20 or so from the hot tap Would a combi be okay? Can you get a combi anywhere near that?

 

[Wangerman]

Not very scientific but using a jug on the cold bath tap we get 30 litres of water per minute I think. What does that translate to in terms of fitting a combi? Think we get 20 or so from the hot tap Would a combi be okay? Can you get a combi anywhere near that?

20 litres from Combi not sure to be honest

Ideal quote 18 L/M for the 30kw Logic +

 

[Gasman77]

Ideal are having a laugh if they are quoting 18 ltrs per min @ 35 Degree rise......and so are you if you think you will get that - will be 12 - 13 tops.

20ltrs per min is unvented cylinder performance, or you might get away with a storage combi.....

For the money id go unvented

 

[Wangerman]

Ideal are having a laugh if they are quoting 18 ltrs per min @ 35 Degree rise......and so are you if you think you will get that - will be 12 - 13 tops.

20ltrs per min is unvented cylinder performance, or you might get away with a storage combi.....

For the money id go unvented

Hopefully I will be able to let you know some time next week

 

[Gasman77]

Let me know what? if you get 18ltrs of hot water from a 30kw combi??

Trust me - you won't

 

[Wangerman]

Let me know what? if you get 18ltrs of hot water from a 30kw combi??

Trust me - you won't

To be honest I will take your word for it I am not a gas installer


As long as it runs the rads and I can have a bath I am happy enough