Installer installed undersized radiators

[diyer]

Hi,
I had a new central heating system fitted last year and always thought it was cold but because I didn't really use it, as the property was being renovated at the time, I didn't think much of it.

I've finally got round to measuring the temps this year and it's freezing! The temps are reaching a max of 12C-13C with the heating on. I found out about undersized rads and worked out the required BTUs from online BTU calculators and found out that the rads are nearly all undersized by a fair bit.

Is there anything I can do legally being that it has been over a year since the installation?

Thanks for any advice.

 

[plumber0808]

I wouldn't go there again. He is probably doing this over and over to customers similar to you.
bin him and get the job done correct.

 

[jase158]

my calcs are oversized but better to be over then under

 

[aplombier]

Over sizing radiators can also be just as bad as under sizing as it will affect efficiency and correct temp returns of these new condensing boilers

 

[jase158]

its not just as bad as customer is warm in there own home, which surely is what we are meant to be doing as "heating engineers" however it is still bad as it will cost more then it should to heat the home.
but as someone said before this would be my estimates as i can not see window/ insulation etc.

 

[stevetheplumber]

pay peanuts get monkeys your wasting your time pursuing this legally after a year better to spend the extra for some bigger rads and treat it as one of lifes little lessons always get 3 or 4 quotes to get some idea of what the right price for a job is also always get something in writting as to what your getting for the money and what it will do once fitted

 

[Bronze_tap]

he went for the B&B option then changed his mind and camped

For the first time in his life...
In the 5 pounds Argos single season sleeping bag in the current Lake District conditions (-6C, 35mph), 700m above see level on the eastern side of Skaffel Pike

Anyway, I assume that any serious user calling himself diyer should know how to do compression/threaded joints.
Have a look on the youtube, get a double convector rad(s), and have a go.
Best with good competent plumber for the first time.
And keep in mind, that plastics doesn't like high flow temperatures for long time... And the underfloor leaks may go undetected for a while...

 

[DirksPlumbing]

Over sizing radiators can also be just as bad as under sizing as it will affect efficiency and correct temp returns of these new condensing boilers

@Chris: You put a like on this comment? Oversizing allows you to lower the flow temperature and therefore minimising heat losses and maximising the gains from the latent heat.

Could someone explain to me the negative effects to expect (except customer spending more on the radiators)? As long as the oversizing is done equally I could not see negative effects at all.

 

[Gray0689]

@Chris: You put a like on this comment? Oversizing allows you to lower the flow temperature and therefore minimising heat losses and maximising the gains from the latent heat.

Could someone explain to me the negative effects to expect (except customer spending more on the radiators)? As long as the oversizing is done equally I could not see negative effects at all.

Well for one building control can and so fail new houses as not energy efficient

 

[aplombier]

It's all about energy efficiency at the boiler so it will condense efficiently and use less gas or use it better thus saving the planet . the flow and returns at the boiler must only have 10c temp difference so if the rads are too big for the boiler then the return to the boiler will be too cold and then the boiler won't condense . Which means you might as well not fit condensing boiler, as stated building regs can now make you rip it all out if they get involved. I'm not the best explainer so hope this is good enough. If you've done level3 about modern system design this should have been taught at that stage.

 

[tamz]

It's all about energy efficiency at the boiler so it will condense efficiently and use less gas or use it better thus saving the planet . the flow and returns at the boiler must only have 20ºc temp difference so if the rads are too big for the boiler then the return to the boiler will be too cold and then the boiler won't condense . Which means you might as well not fit condensing boiler, as stated building regs can now make you rip it all out if they get involved. I'm not the best explainer so hope this is good enough. If you've done level3 about modern system design this should have been taught at that stage.

You are getting things a bit back to front here.

I've also corrected a bit for you

 

[aplombier]

Defo think its 10c but going to check later.
Also what bits back to front tamz

 

[DirksPlumbing]

Defo think its 10c but going to check later.
Also what bits back to front tamz

First of all the lower the return temperature the higher the condensing effect. Anything above 70 degC has to be considered as non condensing range.
The lower the flow temperature the lesser the heat radiation part and therefore the lesser the heat losses in specific in conventional buildings with non reflective membranes, corroded ones or none at all.

The spread only influences the amount of heat distributed into the room. If you use a 55/45 design temperature the spread will obviously be 10 degC. Same on a more extreme 40/30. If you get to lower design temps you will not be able to have a great spread anymore which automatically increases your radiators beyond the increase due to the lower temperatures.

If you go for 60/40 you can keep your rads and pipes smaller but typically your heating pump has to work longer and harder as the friction will be higher. Thus can lead to not being able to use the VP modes on the hopefully A rated pump. The longer boiler run times will also increase losses through the flue. In conjunction with an oversized boiler this will be anything but green.

As far as building control goes they should then fail all surface heatings and heat pump systems? How would they be bothered by bigger and therefore more efficient radiators?
That casts a funny light on those guys waving through uncommissioned boilers being fitted to no standards and not even working.

 

[tamz]

I'll save you the trouble of looking
Older systems were based on an 11º drop. New systems on condensing boilers should be set for a 20º drop.
Condensing boilers only condense when the return temperature is below 55º. This requires oversized rads or a low flow rate and careful balancing.
Big rads that feel cool to touch and low return temperatures mean cheaper bills.

 

[tamz]

Have you got shares in Grundfos Dirk :lol:
Btw most bco's (and i'm sure we have met the same ones) couldn't tell the difference between a paraffin heater and a boiler

 

[DirksPlumbing]

I'll save you the trouble of looking
Older systems were based on an 11º drop. New systems on condensing boilers should be set for a 20º drop.
Condensing boilers only condense when the return temperature is below 55º. This requires oversized rads or a low flow rate and careful balancing.
Big rads that feel cool to touch and low return temperatures mean cheaper bills.

I should learn from you to keep things short and simple.

 

[tamz]

Cut through the bullshyt and get direct to the point is what most people understand

 

[joni os]

Stelrad literature should put this to bed. Mean water temperature / Room temperature, Difference. Means larger rads can produce required heat at lower temperature. Lower temperature means better recovery of latent heat. One of the reasons underfloor heating works well with condensing boilers. Any Building Control who think larger rads mean less efficiency should be challenged.

 

[DirksPlumbing]

Have you got shares in Grundfos Dirk :lol:
Btw most bco's (and i'm sure we have met the same ones) couldn't tell the difference between a paraffin heater and a boiler

I wish I had shares with them. But then it is not exactly an exiting newcomer. Then rather Softing.

Must say I had little contact with building control in Central Scotland. I had been on new builds past Greenock and the islands. The guys there were pretty okay despite the fact you had to pribe them with a fresh coffee on arrival.

But the things I have come across in Central Scotland actually made me doubt seriously. Usually handed over buildings.

 

[tamz]

One of my mates is a bco with West Lothian council and i usually have a pint with him of a Friday along with a few other plumbers. We usually educate him on what to look out for (we all self certify so who cares) as he is totally clueless. He admits himself he hasn't a clue about services. Drain tests and asking for copies of the benchmarks are about his limit when it comes to plumbing and gas.

 

[DirksPlumbing]

One of my mates is a bco with West Lothian council and i usually have a pint with him of a Friday along with a few other plumbers. We usually educate him on what to look out for (we all self certify so who cares) as he is totally clueless...

Former workmate had been made to putty all plug holes in the building prior to the drain test and had to remove it afterwards again.

 

[tamz]

Probably because the numpty bco was insisting on a 100mm drain test (as on an open drain) which is near impossible on a 50mm wc trap seal (it can be done with a bit of luck if you pump it very slowly) because he knows no better. They are clowns.
If you know you are in the right argue your case with them and go over their head but when you do that you better be sure because the next guy who comes out will have read up on it.

 

[DirksPlumbing]

Probably because the numpty bco was insisting on a 100mm drain test (as on an open drain) ...

Very so. That would make Mira shower trays illegal as well. At least the ones with the supplied trap. And a lot of bath traps, urinals with built in trap, some 6l and virtually all 4.5l liter toilets and and and.

By the way the mentioned building had six flats in it.

 

[tamz]

The final test should be done at 40mm as it can't be any higher than the trap seals but they want it as high as it will go
As i said they are mostly clueless clowns and they are supposed to be regulating us. They are not interested and have very little knowledge of what we do. More interest is a walk through the house for structural things which i can see the poit of.
They no longer concern me as i self cert my work so i am outwith their control even for drain tests.

 

[DirksPlumbing]

More interest is a walk through the house for structural things which i can see the point of.

But where are they when you need them. Been on a site, when I walked in I had been impressed by the extra long beam holding half of the houses roof without additional support to find its left hand side held up by an 2x2 upright.

Walked out to see the site manager (as well to request walls to hang the rads. The guy said to me that was found so when they removed the plaster board and they are not going to do anything about.

As the existing radiators were dangling on bowed brittle 10mm plaster board ready to fall of I just left the place to not be seen again. This "feature" was meant to be left as was as well.

 

[tamz]

But where are they when you need them. Been on a site, when I walked in I had been impressed by the extra long beam holding half of the houses roof without additional support to find its left hand side held up by an 2x2 upright.

Upholding and regulating standard my rse. Like all lines of work there are good and terrible and all the shades in between. Luck of the draw who comes out and even then in many cases there are the backhanders to sway there judgement and blight their vision.
Many years ago in Edinburgh it was common knowledge that it was a fiver a drain test if you were having problems with it standing (the tests were done (or not done) by an ex council plumber)

 

[chris watkins]

It sounds like it is country wide then & I though London was bad but reading you two, it just the same, back in my day there were D or S I's (drainage or sanitary inspectors) & that's all they did, so very difficult to pull the wool over their eye's.
Looking at what they sign off now days, it makes me mad.
The public's main protection & our policeman as far a cowboy workers, don't have a cue & don't care, it seems that all they want to do is take the money.
No enforcement mean the Law becomes an bum.

 

[joni os]

Lets not be unfair to building control officers. Thirty years ago Building Regs was a small book with much useful guidance. Now the document is so complex that by the time you have read it the regs will have changed and you have to go back and start at the beginning. Being required to know a little about everything means they will not be experts in a particular field. In general if treated with respect they will be open to discussion of evidence based practice and prove a valuable source of guidance on new rules. Beware of what you hope for. If they were really clued up on all the rules many plumbers would have costly claims against them for notching of floor joists in the wrong place and in the wrong manner. Electricians please also take note.

 

[SimonG]

A building control department should contain experts in all fields, it would be impossible to expect 1 individual to turn up on site and be proficient in all aspects of what needs to be signed off. We are out in the sticks so there is a lot of all, the bc know nothing about oil, things get missed and don't get picked up until you end up going out to somewhere with an issue and then explaining to the customer it's not right and needs this that and the other doing. The cust then gives it to you in the neck for trying to get extra work from the call out.
IMHO bc should send a 'team' to sign off. But that would be a perfect world.

 

[doitmyself]

Over sizing radiators can also be just as bad as under sizing as it will affect efficiency and correct temp returns of these new condensing boilers

It's not really oversizing; it's putting in the correct sized radiator, taking into account the required flow and return temperatures. The reason you have to do this is that radiator output varies with flow, return and room temperatures.

Most manufacturers' literature just quote the output according to BS EN442, which specifies temperatures of 75°C/65°C/20°C (flow, return, room). If you run the boiler at say 75°C/55°C (most boiler manufacturers now specify a 20°C differential) the radiator output will be reduced by about 15%. so you will have to install one which is about 20% larger.

Example:

A Stelrad 600 x 1000 K1 produces 1000W at 75/65/20, but only 850W at 75/55/20.
A Stelrad 600 x 1200 K1 produces 1200W at 75/65/20, but only 1025W at 75/55/20.

So if you need 1000W in a room and are running at 75/55/20 you need the 600 x 1200 rad to produce the required 1000W heat.

The rad may be physically larger, but it's not "oversized" as far as the heat is required.

 

[doitmyself]

The flow and returns at the boiler must only have 10c temp difference, so if the rads are too big for the boiler then the return to the boiler will be too cold and then the boiler won't condense . ... If you've done level3 about modern system design this should have been taught at that stage.

If that's what you were taught, then the teacher needs to go back to school as he was talking nonsense. Unless, of course, you completely misunderstood what he was saying.