Not hot enough!

[Babcia]

Thanks. That is something that I understand and can get my teeth into. Return under 55 (say 50-55) so flow has to be +20 (say 70-75) simple.

In doing a bit of reasearch I came across this on Plumbingpages.com Condensingboilers - destroying the myths:

The system does not need to be designed to condense to achieve the improved efficiency, typically a condensing boiler would have a seasonal efficiency of between 83% and 92% compared with a new non-condensing boiler at 75% and an older boiler type at 55-60.

I just don't want them to be able to come back at me and say 'no the 55 + 20 rule does not have to apply'. Is the argument to counter that 'Oh yes it does if you want the best efficiency from the boiler and reduced gas usage'?

I can understand the above and hopefully it cover the logical argument.

 

[D_Hailsham]

typically a condensing boiler would have a seasonal efficiency of between 83% and 92% compared with a new non-condensing boiler at 75% and an older boiler type at 55-60.

Seasonal efficiency is just a method of comparing boilers; it has nothing to do with the seasons of the year.

The seasonal efficiency of a boiler is calculated using a formula (which varies with the type of boiler, regular, combi, etc). As an example the formula for calculating the SA of a regular condensing boiler is:
E = 0.5(Efull + Epart) – 2.0 – 4p

Where Efull is the efficiency at Full Load, Epart is the efficiency at 30% load and p is 0 if the boiler has electronic ignition and 1 if it has a permanent pilot light.

 

[bengasman]

anybody who self certifies boilers knows about the 55 degree story. it is part of the course that is compulsory for us. above this the efficiency of a boiler drops rapidly. still better than an conventional boiler, compare it with double glazing that does not shut properly; better than an old sash, but still loosing heat
there is no argument against it and anybody attempting to talk his way out of it, exposes himself as a cowboy.

 

[D_Hailsham]

Looking back at the temperature figures again, the Flow temp is OK; it's the Return temp which is much too high. Could the problem be caused by very badly balanced radiators, i.e the lockshield valve is so far open that there is very little drop across the radiators? Would this cause the boiler to modulate down to so it was old supplying 8kW.

As the Developer the following questions:

Designed room temperature
Designed minimum outside temperature
Designed Flow temperature
Designed temperature drop across the radiators.
How was the system balancing carried out. It should be done using thermometers - many installers just use guesswork.
Has a weather sensor been fitted.

Don't get fobbed of with a spiel about SAP ratings.

Just a thought. You say it is a new development. Have you asked your neighbours - preferably in a similar house - if they are experiencing problems?

 

[Babcia]

What an education! Thanks so much. I love the comparison with double glazing - that I can understand. Having looked up 'lockshield valve' (so that is what itis called), I don't intend to delve into that myself but will have that gem tucked away as a suggestion - thay may think I know what I am talking about.

Thank you for the list of questions, I can appreciate the significance of most of them.

Yes, the neighbours have problems too. They are having their rads upgraded too but it was our discussions that led to boiler settings that has opened up another avenue for correction that I need to draw to their attention. It is the enquiring mind, the fact that I am at home all day - and cold - that drives me on and having such great people like yourselves who give up their time to help that makes the world such a great place. Thanks you guys.

I expect the plumbers on Friday or Monday so I will update with a posting.

 

[Babcia]

Happy New Year to you all! (I wish it was a warm one)

From my last posting you could not make it up if you tried. Needless to say, things went from bad to worse. Due to the upgrade in size some new rads were too big so different sizes had to be ordered to fit into available space. That was all completed by Monday night when the following days were a balmy 9 degrees. Due to uncertainty about heat availability Christmas had been moved to another house and it was too late to move it back again. However, on Saturday 27th full of confidence we had invited children and baby grandchildren over. The heating had been on since 5.30am, the hall stat had been set at 22. It clicked at 16. Both lounge rads were set to 5 and the lounge temperature was 13 at 8am. Rads barely hand hot at top and cool at bottom. I tried to bleed them - no air. there was no emergency contact for plumbers, I found a fan heater and oil fired radiator and kept the place warm that way with heating on constant to keep other roms warm. I did turn off the only other rad on the ground floor with a trv and it did seem to help heat up the lounge rads a bit. Obviously this is all not right and I expect the plumbers back on Monday. I only have one question to ask. What is the realistic expectancy for a room to reach the required temperature when the heating starts in the morning? I appreciate that the answer will probably be - it depends on the external temperature - and I accept that but it seems to take 6 hours to get the lounge up to 21. I know that is unrealistic - well I hope it is unrealistic but is there a span say 1-2 or 1-3 hours that would be acceptable? If you don't have an intelligent system which knows what the external temperature is, what is the acceptable time in ALL circumstances that the set temperature should be reached? I am getting very disheartened with the system, plumbers etc and need some benchmark to hang on to to retain my sanity. Any guidelines would be much appreciated. Thanks in advance.