Advice on boiler replacement

[Ambra]

First - sorry for long post. But I am getting confused and hopefully someone can set me straight here.

So, I have looked on the forums, read up on the websites, etc., and decided that Viessmann 200 would be great, including weather compensation. We are replacing 20+ years old boiler, and we want a combi one.

I had a few heating engineers come to have a look at the job. First one left a good impression, talked me through 100-W and 200-W, and gave quote for both (35kW), so I can choose how much I can spend. He highlighted the issue of gas supply to the boiler - it is 15mm currently and would need to be upgraded to 22mm. He looked in the garage, and there is a bigger pipe going into the space between ceiling and the floor, and he guesses that it would be going at that size up to the cooker (on the side of the kitchen closer to the garage, the boiler is on the opposite corner of the house to the meter). Told me I would need to powerflush the radiators and fit magnaclean filter. Qoute for 200, including VAT came to about £3.4k.

We do not want to move the boiler from its current location, as it suits us, there is plenty of space in kitchen. Have to say, all the guys who looked around suggested to move the boiler to the airing cupboard, but we don't really want to.

The second guy spent much less time in the house, but still seemed to know what he is talking about.

Well, the third guy... As soon as he came in through the door he sort of started pushing me towards the cylinder. Then he started thinking where else in the house he could fit the boiler (just not in the kitchen where I want it to stay) - airing cupboard, garage, loft... Vented system, unvented system... He was going on and on and on. I told he I want Viessmann before he came, and he came in trying to sell me the Intergass one (as he can carry the spares for this one, and they are much better than Viessmann ones anyway, and that it takes so long to fix a Viessmann if it goes wrong, etc). He said there is no way 22mm gas supply would be enough, we would need probably 35mm, and he could put on the outside of the house (I took him upstairs to the bedrooms where the pipe is likely to be going under the floor and we are in the process of redecorating them, so there would be no problem to get to the pipes).

He went up to loft and got stuck with the idea of putting the boiler up there. How he would get gas from the garage up to the garage roof, on the side of the window and into the loft (garage is attached), and condensate he could just drip on the garage roof. Is this a normal practice???

Can someone give me an idea if I am likely to need 35mm gas supply to the boiler? Since he is the only one who mentioned it (others were happy with 22mm)? I have someone else coming to have a look at the job today, so will see what he says.

 

[PEDANTICVINDICTIVEMAN]

Go electric heating and do us all a favour

 

[Ambra]

Thanks for wise words... Any suggestions on electric heating?

Or did I step on the wrong foot?

 

[D_Hailsham]

So, I have looked on the forums, read up on the websites, etc., and decided that Viessmann 200 would be great, including weather compensation. We are replacing 20+ years old boiler, and we want a combi one.

I'll stop you there, if you don't mind.

You might want a combi, but have you checked if a combi is suitable?

How many live in the house?
How many bathrooms and shower rooms?
What is the incoming cold water flow rat at the kitchen tap?
What is the dynamic pressure of the incoming cold water?

 

[Ambra]

So, I have looked on the forums, read up on the websites, etc., and decided that Viessmann 200 would be great, including weather compensation. We are replacing 20+ years old boiler, and we want a combi one.

I'll stop you there, if you don't mind.

You might want a combi, but have you checked if a combi is suitable?

How many live in the house?
How many bathrooms and shower rooms?
What is the incoming cold water flow rat at the kitchen tap?
What is the dynamic pressure of the incoming cold water?

Yes, we went through this with all heating engineers. None of them said that combi would not be suitable. Even the last one did say we shouldn't have one, it is just that he would prefer unvented system.

2 people live in the house.
There is main bathroom with electric shower and ensuite with mains mixer shower. (we don't use the bath, probably only once o twice a year, we much more prefer showers)
Cold water flow rate at kitchen tap is about 16l/min.
I do not know the dynamic pressure, have no way of measuring that.

 

[D_Hailsham]

Yes, we went through this with all heating engineers. None of them said that combi would not be suitable. Even the last one did say we shouldn't have one, it is just that he would prefer unvented system.

That makes a change.

2 people live in the house.
There is main bathroom with electric shower and ensuite with mains mixer shower. (we don't use the bath, probably only once or twice a year, we much more prefer showers).

The electric shower still takes cold water from the mains and heats it up. So you could have two showers going at the same time.

Cold water flow rate at kitchen tap is about 16l/min.

That's low for a combi. With two showers going, each one will only get 8 litres/min at the maximum and probably less than that. Check the flow rate you are getting from both your showers.

Don't forget that everything in the house is fed from the one source - the incoming cold water mains. So flushing the loo, turning on the washing machine etc will have an effect on someone standing under the shower.

I do not know the dynamic pressure, have no way of measuring that.

To do the job properly, you need a meter. However there is a simple way of checking if it is adequate.

If you have a garden tap fed direct from the cold mains, measure the flow rate at the kitchen tap, using a marked bucket and watch, firstly with the garden tap off and then with it full on. The smaller the difference in the flow rate, the higher the dynamic pressure.

 

[vulcancontinental]

Electric heating? The smiley is the clue.

Everyone has their own ideas. Many guys will disagree with me; it’s up to you.

FWIW: I like to keep a combi near the taps you use most, the kitchen tap, less wasted hot water when you’ve turned the hot off.

I really don’t like putting a combi in the loft which is a far away from the sink tap as you can get. I worked it out once that it’ll cost over £30/ year in wasted gas just heating the water to sit in 10m of pipework between boiler and tap growing cold after the tap is closed. That’s not counting the inconvenience of wasting the cold you run off if you’re on a meter while waiting for the hot to arrive and the time spent twiddling your thumbs. If your airing cupboard is a long way away the same applies.

I’ve also attended frozen combis and pipework in a loft when the frost protection proved useless because a power cut meant it didn’t work.

Possibly your pump and valves are in the airing cupboard which means all connections are easy to connect to for a combi (except gas).

Installers are conscious of being competitive so want to suggest things that will not mean his price will be higher than another installer.

35KW is a fair old output and if you have one of the 6 or 8 ring cookers which currently seem very popular and a gas fire or two you may well need to increase the size of the gas pipe throughout its length.

Condensate should be taken to a drain and I prefer a soil or internal waste pipe when I can as it has warm air in it and is less likely to freeze.

Don’t know about Intergas but they get good reports on this site. I know Viessmann and like them. If the installer has been on their 100 and 200 courses you’ll get a five year guarantee. There are a lot of good boilers.

Powerflush and filter but I don’t like the Magnaclean.

If you’re going to stay in the house and it’ll be your home worry less about the money and more about the installer. Ask for details of his last three installs and don’t be shy, go speak to them. If he baulks at that go somewhere else. If you like the work and the old customers do as well, trust his advice.

Personally I’m not a fan of combi’s; if you get one get an electric shower and then you’ll have somewhere to get clean when it goes wrong. With a cylinder you have the opportunity often of installing an immersion heater for the breakdowns.

How many bathrooms do you have? How many people in the household?

Did he check water flowrate and pressure on the incoming main? Combi’s must have good supply.

There’s lots more but that’s enough to get on with.

I’m an opinionated old git, take what you want from the above and throw the rest out.

 

[Ambra]

Thanks, I'll try measuring the water flow with garden tap open. (thanks for the advice - I haven't though about this)

We never have showers at the same time. We don't even use the electric shower - it is for guests. (Sorry - we do use it, when we run out of hot water at the weekends!)

I'll check the flow rate from the electric shower with the mains one one, but also, the mains shower has a pump, as hot water pressure dropped significantly when the shower was changed 10 months ago.

We both are from the continent, and we had combi boilers before - that always suited us.

 

[Ambra]

FWIW: I like to keep a combi near the taps you use most, the kitchen tap, less wasted hot water when you’ve turned the hot off.

I really don’t like putting a combi in the loft which is a far away from the sink tap as you can get. I worked it out once that it’ll cost over £30/ year in wasted gas just heating the water to sit in 10m of pipework between boiler and tap growing cold after the tap is closed. That’s not counting the inconvenience of wasting the cold you run off if you’re on a meter while waiting for the hot to arrive and the time spent twiddling your thumbs. If your airing cupboard is a long way away the same applies.

I’ve also attended frozen combis and pipework in a loft when the frost protection proved useless because a power cut meant it didn’t work.

Possibly your pump and valves are in the airing cupboard which means all connections are easy to connect to for a combi (except gas).

Installers are conscious of being competitive so want to suggest things that will not mean his price will be higher than another installer.

35KW is a fair old output and if you have one of the 6 or 8 ring cookers which currently seem very popular and a gas fire or two you may well need to increase the size of the gas pipe throughout its length.

Condensate should be taken to a drain and I prefer a soil or internal waste pipe when I can as it has warm air in it and is less likely to freeze.

I’m an opinionated old git, take what you want from the above and throw the rest out.

Thanks so much for this! It is very useful. Your view of putting the boiler in the loft is similar to mine - I don't want it there. Pain to get to if needed (ok, I do have ladder there, but still). The loft hasn't been well insulated yet (that is the job to do asap after we complete on the house), and according to the last engineer, it will be great, as boiler will heat up the loft space as well and we will not need insulating it!!!! (You can see that I really trust the guy)

The current location has all that is needed, apart from gas supply pipe that needs to be upgraded, and I am fine with them lifting the boards upstairs (the chipboard sheets), as we are going to redecorate anyway! (And fix the squeaky floor in one of the bedrooms they will need the access too).

We have a gas fire currently, which we are looking to get rid off in due course as well, and there already is an electric shower if something goes wrong with the boiler, so we can wash up. We have budgeted for this job when we bought the house, and I don't expect to get it done for £2k, but I just want to make sure that I get a fair quote, so I want to hear what others say, so make a little bit 'informed' decision.

 

[PEDANTICVINDICTIVEMAN]

I'll do it for £10,000 an hour plus materials plus tea made with proper milk, non of that dishwater green top stuff, I will be giving quotes to other customers and checking which tea and milk they will supply me with if I agree to do their job, can anyone tell me what tea and Milk I should be looking for, 5 other customers wanted to palm me off with bloody Red top rubbish, do you think they were trying to rip me off, think I will get another 10 quotes in case one of them comes up with that horrible powdered milk yuk, cowboy customers trying to push me towards their favorite unreliable milk stuff also meant to ask about sugar, any advice regarding that, sacharin or lumps ?

 

[compheat]

I Like Intergas boilers

 

[transam]

I'll do it for £10,000 an hour plus materials plus tea made with proper milk, non of that dishwater green top stuff, I will be giving quotes to other customers and checking which tea and milk they will supply me with if I agree to do their job, can anyone tell me what tea and Milk I should be looking for, 5 other customers wanted to palm me off with bloody Red top rubbish, do you think they were trying to rip me off, think I will get another 10 quotes in case one of them comes up with that horrible powdered milk yuk, cowboy customers trying to push me towards their favorite unreliable milk stuff also meant to ask about sugar, any advice regarding that, sacharin or lumps ?

Persnally I quite like that Yorkshire tea , I also had apparently some captains scott tea , eg it was made to the same recipe as what scott took down to the south pole not bad , would agree with the red top comments
Full fat milk for me !

Any way OP u may not have noticed but we are in a recession , do your bit for the UK economy , buy British !

 

[kevplumb]

I Like Intergas boilers

somebody has to i suppose

bet your a fan of ideal as well

 

[PEDANTICVINDICTIVEMAN]

I like Ideal, I got my free large wallet full of gumpf

 

[Axel]

Biscuits are a major factor...