OT Are all heating engineers touchy?

[charles]

What's wrong with an old boiler? Mine dates from 1989 - also Glowworm.

[Dave Liquorice]

It might be rather inefficient, look it up in the SEBUK database

There could be a 20% or so reduction in your gas consumption between an old cast iron non condensing boiler and a modern condensing one. Note condensing does *not* mean combi.

24 years old, spares could well be getting a bit thin on the ground. Wouldn't be pleasant to have to do a unplanned and rushed boiler swap in the middle of winter should it breakdown and no spare(s) available. Better to do a bit of planning and research, then schedule as swap at your convience (if that is the conclusion) to a boiler best suited.

[Onetap]

There is, I believe, little difference in the efficiency of a modulating combi boiler at various outputs, providing that the return temperature is low enough to ensure that it is in the condensing region. A search for efficiency graphs should confirm that.

Multiple boiler installations were usually sequenced so that the minimum number of boilers were firing, i.e., No 2 fired when No 1 was on 100%, No 3 fired when No 2 was on 100%, etc..

I was told (by a manufacturer) that having all the boilers firing at the same part-load would be more efficient.

[Andy Cap]

All true. 65% against 90% in my case. I'm really in no haste to dump the old boiler, because I doubt all the blurb that there's these great savings to be made, because this old boiler has cost me virtually nothing over the years and they never factor in replacement costs or faults, BUT with gas getting ever more expensive, the cost saving *is* becoming a factor and as you say, getting hold of a gas valve will be nigh-on impossible. There's the odd second-hand one on Ebay, even one new one I noticed the other day, but of course that understandably comes at a premium price.

[Andy Cap]

I never actually posted anything. I was just looking through previous questions and the impression I got was the professionals were pretty off-hand, which I can understand, but if they want a closed-shop then have a private members group which you have to register for, it's not difficult. When you hear all the horror stories of people being ripped off by so-called professionals, it's to be expected that customers will want to get better informed, before accepting any old quote.

[The Natural Philosopher]

700 quid buys a lot of gas...

[Adrian]

It's only three times the February (mains) gas bill for the 70m2 cottage we spent the winter in...

[Peter Crosland]

Why should a professional who has invested time, effort and money in learning his, or her, trade give you free advice? The rule of thumb is that free advice is worth what you pay for it. Unless there is some reasonable prospect of getting some work then you should do your own homework. There are plenty of websites and library books to help you.

[Tim Watts]

On Wednesday 10 July 2013 11:55 Peter Crosland wrote in uk.d-i-y:

Why shouldn't he? A large number of people on uk.d-i-y are professionals in some area or the other and contribute free advice in their area as well as others.

Paid advice is Ok but how do you know the person you are paying isn't an idiot?

I would suggest the only way is by taking a consensus of opinion from people who have a track record of knowing something.

And besides, it well might come back as a paind job for one of the professionals.

[Andy Cap]

... and yet there are several electricians on here who give advice. The odd question from some stranger in another part of the country is hardly likely to affect their business. There are loads of boards where you can get advice on a whole range of stuff. If a guy was actually helpful and lived in the vicinity, I'd probably offer him the job !

[polygonum]

If you have got a cylinder which has a halfway decent coil (or might in the future have one), then 7.7kW is unlikely to be sufficient even to maximise the transfer of that coil. Without any heat going anywhere else.

[RobertL]

That is a reasonable point, but I think it is not the point that the OP was making. He was not complaining that professionals did not respond but that sometimes they did respond only to say they would not help.

Robert

[Fredxx]

I use free advice to gauge how competent the professional is as well as determining his friendly nature. If someone is seemingly obstructive, that is how I would anticipate him to be after any work when something has gone wrong.

That is my policy in my own field and I feel it works and gives confidence to my customers. The alternative is giving the perception of hiding my ignorance.

[John Rumm]

Its not really that difficult with a spreadsheet - and in reality you will get a much more accurate answer than you will from most "pros" simply because they don't have the time to do the work required just for an estimate.

If you start here:

It will show you how to work out what the house heat loss is likely to be. Note that if you are going for a combi boiler, then that becomes a moot point since you will need to size it for the require hot water performance.

One you have figures for "worst case" and "normal" you can try and pick a boiler that will cope with the former, but also modulate down low enough for the latter.

[John Rumm]

For which, a lickable clink:

[John Rumm]

When I did the numbers on my previous place 3/5 bed semi, it was about

8.6kW IIRC.

[Andy Cap]

I've just finished mine, adding in the water heating and it's come out at 8.854kw !

[John Rumm]

You tend to find that many which have very high outputs to the DHW have a lower normal output to the rads anyway. On the 35kW one I used at the last place its max output to the CH was 24kW, and it modulated down to about 8kW

[John Rumm]

Indeed - although depending on use patterns that may not actually matter. Many folks cope with a cylinder heated from either a 3kW immersion or from a slow indirect coil dumping only 3 - 5kW into it.

(my "fast recovery" unvented cylinder mind you can take heat at 22kW if the boiler can manage it).

[ARW]

They do not have to give free advice.

The easiest way that they can do this is by not posting replies to a forum.