Dummies guide to boilers

oceanclub

Have bought a 3-bed 1-bathroom (ensuite to be added) Victorian-era house that needs doing up and one thing that needs to be installed is a new boiler, something that (given I've been renting 'til now) I have no clue about other than 'they produce hot water'.

Looking at Which magazine I see they highly recommend the brand Worcester Bosch, but which one I choose is another thing. A 'combi boiler' seems to be one that doesnt' require a hot water tank, correct? Is there a downside to this? (Getting rid of an old wardrobe containing the current hot water tank would be great). Are all current boilers compatible with both thermostats and manual controls?

If someone could point me to any intro guide to boilers for the layperson, would appreciate it.

P.

donedl1

https://www.worcester-bosch.ie/products/boilers/explained. This may help.

Dtp1979

oceanclub wrote: »

Have bought a 3-bed 1-bathroom (ensuite to be added) Victorian-era house that needs doing up and one thing that needs to be installed is a new boiler, something that (given I've been renting 'til now) I have no clue about other than 'they produce hot water'.

Looking at Which magazine I see they highly recommend the brand Worcester Bosch, but which one I choose is another thing. A 'combi boiler' seems to be one that doesnt' require a hot water tank, correct? Is there a downside to this? (Getting rid of an old wardrobe containing the current hot water tank would be great). Are all current boilers compatible with both thermostats and manual controls?

If someone could point me to any intro guide to boilers for the layperson, would appreciate it.

P.

Worcester boilers are no better or worse than any other top brand. Viessmann Ariston or wolf are as good if not better.

oceanclub

If not living in a huge house (in our case, we'll have a three-bed, 1 kid, 1 bathroom and in future one en-suite) is there any reason _not_ to get a combi boiler? On the plus side it frees up need for a cylinder (a retro-fitted one currently takes up room in an awful cupboard on our landing) plus only heating water you actually needs seems far more economic.

P.

Dtp1979

oceanclub wrote: »

If not living in a huge house (in our case, we'll have a three-bed, 1 kid, 1 bathroom and in future one en-suite) is there any reason _not_ to get a combi boiler? On the plus side it frees up need for a cylinder (a retro-fitted one currently takes up room in an awful cupboard on our landing) plus only heating water you actually needs seems far more economic.

P.

An ensuite and bathroom is stretching the ability of a combi

filbert the fox

Dtp1979 wrote: »

An ensuite and bathroom is stretching the ability of a combi

Is this true? There are 5 sinks in our gaff and are you saying that a combi can only serve one?

Dtp1979

filbert the fox wrote: »

Is this true? There are 5 sinks in our gaff and are you saying that a combi can only serve one?

Depending on the combi.
Turn on every single hot outlet and see what happens

corkgsxr

Dtp1979 wrote: »

Depending on the combi.
Turn on every single hot outlet and see what happens

Ahh that's not really fair. With a decent mains it's not a issue. If lived in a house with that setup and a 28kw worchester. Even if your in the shower and someone runs a tap pressure drops a bit but It's still better than a electric shower.

antoinolachtnai

There is also the small matter of being in breach of the bye-laws if you are in Dublin and install a combi boiler without a break tank and a pump. A break tank and pump makes it awkward (it is as easy to accommodate a hot water tank).

A lot of people like to ignore this rule. It is fine if it works, but if it doesn't work, or if the pressure is turned down during an emergency, you don't have any comeback. If you are on low ground it might be worth taking a chance on.

What determines whether the thing will work is not the number of sinks but the number of occupants. If you have 2 occupants hitting the showers at once I don't think you'll have much hot water.

Dtp1979

corkgsxr wrote: »

Ahh that's not really fair. With a decent mains it's not a issue. If lived in a house with that setup and a 28kw worchester. Even if your in the shower and someone runs a tap pressure drops a bit but It's still better than a electric shower.

And what if someone else opens a another tap or 2?

K.Flyer

The break tank / pump configuration gives you a more reliable flow of water which at times can be hit and miss when direct mains is used (by-law aside).
My recommendation, if the budget allows, is a pump with a speed control unit. This is a pump that modulates the flow rate depending on the demand, allowing for better pump life and is usually quieter than straight on / off pumps.

corkgsxr

corkgsxr wrote: »

Ahh that's not really fair. With a decent mains it's not a issue. If lived in a house with that setup and a 28kw worchester. Even if your in the shower and someone runs a tap pressure drops a bit but It's still better than a electric shower.

Why? it's a fundamental difference between stored hot water and combis.

A combi will have limitations(less so with the larger KW boilers) on how many taps can be opened compared to stored hot water and the time taken/water wasted waiting for the changeable hot water to reach the tap, none of this is a problem if the home owner fully understands and is happy to adapt to the different characteristics.

I'm also in the camp of if you need a break tank a combi isn't for you as stored hot water does what it says on the tin and you have the benefit of a immersion.

I also think if you want to move away from gravity hot water in something larger than a flat a unvented cylinder will give you the benefits of stored hot water with the increased pressure performance of a combi.

antoinolachtnai

antoinolachtnai wrote: »

What determines whether the thing will work is not the number of sinks but the number of occupants. If you have 2 occupants hitting the showers at once I don't think you'll have much hot water.

But that's like saying if your only useing one room you only need to fit a small boiler.

Any hot water design should be able to meet maximum usage and as installers we should be meeting that simple benchmark because we can.

Now if a homeowner wishes to reduce their hot water performance where is our cut off, for me it's anything more than two taps/shower looking for optimum performance at the one time.

antoinolachtnai

I agree absolutely. (I'm not in the trade by the way.) At the end of the day though, the punters have to decide what they want to pay for.

Sometimes you come across houses with a load of bathrooms and relatively few bedrooms. Some people like living in a house that is too big for them and must intend to hang on to it for a long time. Whether they have a problem or not will depend on the number of occupants and how much water they use. Some people like the idea of having instant hot water despite all the problems with combi boilers for larger houses.

Every so often I see and hear about combi boilers being recommended or installed because the installer is a lazy sod and he thinks a combi is the easiest, quickest way to get in and out of the job (and with a bit of copper in his boot). That is obviously not good.

corkgsxr

Dtp1979 wrote: »

And what if posomeone else opens a another tap or 2?

ju

Never found it a issue being honest about it.

corkgsxr

corkgsxr wrote: »

ju

Never found it a issue being honest about it.

Obviously your partner loves you very very much, my wife had a habit of turning a cold tap on or flushing the loo when I'd be in the shower mid verse of Bon Jovi's Living on a prayer.

DGOBS

oh jesus, now I'm gonna have nightmares!!
Wish I hadn't read that last post just before bedtime

Wearb

gary71 wrote: »

Obviously your partner loves you very very much, my wife had a habit of turning a cold tap on or flushing the loo when I'd be in the shower mid verse of Bon Jovi's Living on a prayer.

Well you deserved that, if you are going to murder a good song in the shower. ..... still, I suppose if we can't sing in the shower, where's the fun in it.

I have to admit my singing is a bit brutal, it's was so bad there for a while that I was wan.....ted..... Dead or A...live......

DGOBS

DGOBS wrote: »

oh jesus, now I'm gonna have nightmares!!
Wish I hadn't read that last post just before bedtime

Just doing my bit for Halloween

Dtp1979

gary71 wrote: »

I have to admit my singing is a bit brutal, it's was so bad there for a while that I was wan.....ted..... Dead or A...live......

Say it isn't so Gary

DGOBS

....find a happy place.. find a happy place....

oceanclub

antoinolachtnai wrote: »

There is also the small matter of being in breach of the bye-laws if you are in Dublin and install a combi boiler without a break tank and a pump.

Genuinely curious, what bye-law is this? Did it come into effect with the advent of combi-boilers or is it some older rule that combi-boilers inadvertently break?

P.

antoinolachtnai

It is here: http://www.dublincity.ie/main-menu-services-water-waste-and-environment-your-drinking-water-builders-and-developers

This rule has been in place since the '70s. It is basically not allowed to heat water that comes directly from the water main without an intervening tank. As I understand it, the reason for this is basically the conservation of water pressure at peak times. Poor water pressure is to this very day a very real problem at times in Dublin in some conditions and in some areas.

See section 39 of the regulations.

For the protection of the water supply and in the interests of the consumers, water which is used for the supply to any flushing apparatus or for the cold water supply to any bath, shower bath, wash basin or other fittings or apparatus, or to any domestic direct or domestic indirect system of hot water supply of the double feed type, or any domestic water heating apparatus, shall be drawn from cold water storage cisterns of feed cisterns.

and 59:

Every Type of apparatus in or by which water supplied by the Corporation is heated shall be supplied from a cold water feed cistern.

It is not a matter of 'inadvertently breaking' the rule. It is just not allowed, either by the spirit or the letter of the law. Direct connections to the mains are only allowed for drinking water.

oceanclub

Thanks for that. Is a combination of water tank in attic + combi-boiler still better ("better" in terms more energy-efficient and taking up less space in the house) than a convention boiler with hot water press? (I'm making the assumption that combi-boilers only heat the water you need and are therefore more energy-efficient.)

P.

oceanclub

oceanclub wrote: »

Thanks for that. Is a combination of water tank in attic + combi-boiler still better ("better" in terms more energy-efficient and taking up less space in the house) than a convention boiler with hot water press? (I'm making the assumption that combi-boilers only heat the water you need and are therefore more energy-efficient.)

P.

Brake tanks for combis are rarely fitted to meet water regs, they are fitted because the incoming water mains is insufficient to run a combi.

Good system design is paramount when discussing the characteristics of different heating and hot water system.

Combi boilers or system boilers can lose their perceived benefits if fitted badly.

Combi were designed for flats and as the boilers performance improved they started to appear in small homes.

Fitting combis in larger homes brings the home owner closer to the point where the design can work against you ie.... Long pipe runs between hot water tap and the boiler, lots of time/water wasted as you wait for the water to travel from the boiler to the tap

The best system is the simplest.

oceanclub

gary71 wrote: »

Brake tanks for combis are rarely fitted to meet water regs, they are fitted because the incoming water mains is insufficient to run a combi.

Presumably though one has to fit the brake tank anyway to comply with the bye-laws? (I presume there might be a problem attempting to sell a house not compliant at least?)

Fitting combis in larger homes brings the home owner closer to the point where the design can work against you ie.... Long pipe runs between hot water tap and the boiler, lots of time/water wasted as you wait for the water to travel from the boiler to the tap

Conversely though, wouldn't the system boiler be wasting money heating up water to sit in the hot water tank and those pipes?

P.

antoinolachtnai

Well, the tank is still taking up space in the house and it is something that needs to be maintained. You will need a pump as well as a tank, so you might as well put the tank on the ground floor rather than putting it in the attic. The pump is what makes the whole thing expensive and awkward to do. It might be a good solution for small houses with few occupants.

I researched this before and after it all my suggestion is that if space is at a premium but you want to be able to get hot water fast, get a rapid-recovery hot water tank. The fast recovery means there is a bigger than standard coil in it. This means that the water will heat much faster when you turn on the boiler. If you want more pressure on the shower, you can put a pump on it. (In the end, I did not get a rapid recovery tank myself, the tank I had was not too old and it wasn't worth my while replacing it.)

It is really not wasteful if you heat the water at times when you need it and use up most of the water you heat. If there are a few people in the house there's not much waste. On the other hand, if there is just one person in the household, this is not so true.

As has been said, a combi boiler in a 'stressful' situation (long runs, a lot of demand, etc.) could be very disappointing. Very hard to do anything about it if you are unhappy with it after it is installed either.

In general, as has been said, the more standard and simple your system is, the less likely you are to have a problem (and if you do have a problem, there is a much higher chance that you will be able to get it fixed quickly).

oceanclub

antoinolachtnai wrote: »

Well, the tank is still taking up space in the house and it is something that needs to be maintained. You will need a pump as well as a tank, so you might as well put the tank on the ground floor rather than putting it in the attic.

Could the whole lot go into the attic? (We have a low roof so can't foresee us doing an attic conversion ever). Our ground floor space is at a premium - and the current hot water tank is a retrofit sitting in the middle of the upstairs landing. Which is why a combi-boiler seemed ideal.

The pump is what makes the whole thing expensive and awkward to do. It might be a good solution for small houses with few occupants.

Just to be clear, a combi-boiler always needs a pump? Is that irrespective of the water pressure coming into the house? I presume a pump is not needed if tank is in attic? (Our apartments both had pumps which I presume is a result of having the water tank on the ground floor?)

This means that the water will heat much faster when you turn on the boiler.

I wouldn't be too bothered by that as if I do install a system it would have remote access anyway so if I'm on the way home and decide I want a shower, I can (hopefully) turn on the water remotely. I guess my priorities are:

* saving space - not hot water tank, or at worse one in attic
* energy-efficient
* powerful showers!

I had thought the combi-boiler the holy grail for this, I guess not. I suppose the first thing I need to do at least is get the mains water pressure checked.

P.

oceanclub

oceanclub wrote: »

Presumably though one has to fit the brake tank anyway to comply with the bye-laws? (I presume there might be a problem attempting to sell a house not compliant at least?)

Nobody cares.

oceanclub wrote: »

Conversely though, wouldn't the system boiler be wasting money heating up water to sit in the hot water tank and those pipes?

P.

Stored hot water is more simplistic, it works very well, you have a secondary hot water source with the immersion, stored hot water is more of a constant in respect of user satisfaction, with a secondary return your hot water can be at the tap instantly(reducing water wastage)and when fitted correctly taking into account your hot water usage can be very efficient.

Combis are very fashionable and when fitted by a real plumber(most aren't) work well but most combis fitted in place of stored hot water tend to annoy the home owner as it wasn't what they expected/wanted.

antoinolachtnai

If you want powerful showers in your main bathroom and in your en suite at the same time then a combi is not for you. If having to wait a little while for the water to heat up then a combi doesn't give you that much advantage in your situation.

A combi requires mains pressure. The pressure from a tank two storeys up is not sufficient for a combi. You need a pump. Or else you can run it off the mains pressure but that is at your own risk.

If you want to have the tank in the attic, you can, but it will mean that you will be running mains up to the attic to a tank and then down to the boiler, and you will then be taking the hot water from the boiler to the various locations in the house by the most direct possible route. You can do it, and maybe it would make sense, but it might be a lot of extra plumbing work. It would probably be easier to relocate the cylinder. Maybe there is space under the stairs or in the corner of a bedroom or somewhere?

As the man says, the simplest solution is the best.