Ideal Minimiser FF80 Problems/Replacement

[XrayDave]

Hello folks!

Happy New Year!

1st Post.

I have an 11 year-old Ideal Minimiser FF80 which has been trouble since the get-go 11 years ago. Aluminium Oxide a constant headache, burnt out electrodes, pcb replacement, yada-yada.

Had a new heat exchanger fitted around 18months/2yrs ago. Boiler broke down 2 days ago (30th Dec) and BG engineer tells us that the heat exchanger has failed AGAIN and that basically we need a new boiler.

Some questions..

1) Given that this boiler is well-known to be a lemon, is Ideal (or BG who fitted it 11 years ago and have anually "serviced" it since) liable in any way - the boiler not being "of merchantable quality" or "fit for purpose"??

2) Given that we will be without c/htg and hot water (except by electric convector heaters & immersion heater) for the next 5 days at least, should we expect some compensation from BG as we are on their top "Homecare" package?

3) I hear that Wocester Bosch and Vaillant are the best condensing boilers to go for. Have short-listed the Worcester Bosch Greenstar 40 CDi and the Vaillant ecoTEC plus 637 but I have no idea if one is better than the other - or indeed whether these are a "for like" replacement for my Ideal Minimiser FF80.

4) The system that I have feeds 14 radiators (mainly doubles) in a 4-bed detached house with 2 bathrooms on 3 floors. There is an open-topped expansion tank in the loft and a large copper hot water cylinder in the airing cupboard.

Ideally, I'd like to get rid of the expansion tank in the loft.

I have also picked up whilst trawling the net that there is a possibility that the large copper hot water cylinder should be replaced (can someone confirm this please?)

If, as seems likely, we end up with a new boiler, what shold we have changed to make the system more efficient?

We do not (at present) have any radiator valves on any radiators.

Could we have a separate thermostat/valve to shut off heating to the top floor as it gets very warm up there whilst the botton floor is distinctly chilly.

Lots of questions I know, but any help & advice would be gratefully received.

Happy New Year to all,

Dave

 

[D_Hailsham]

1) Given that this boiler is well-known to be a lemon, is Ideal (or BG who fitted it 11 years ago and have anually "serviced" it since) liable in any way - the boiler not being "of merchantable quality" or "fit for purpose"??

Unfortunately any possible liability expires after six years. In any case it is the supplier who is liable, not the manufacturer or whoever services it. Though you be might be able to argue that a replaced component is faulty if it fails. If, however, the component fails more than two years after installation it is your responsibility to show that the fault was present when the component was installed.

should we expect some compensation from BG as we are on their top "Homecare" package?

I doubt it. Read the Homecare Terms and Conditions carefully and you will find plenty of get-out clauses such as using their "best endeavours" etc.

3) I hear that Worcester Bosch and Vaillant are the best condensing boilers to go for.

That depends on who you ask.

The system that I have feeds 13 radiators in a 4-bed detached house with 2 bathrooms on 3 floors. There is an open-topped expansion tank in the loft and a large copper hot water cylinder in the airing cupboard.

Work out your heating requirement by using one of these calculators:

Sedbuk Boiler Calculator

EST online boiler calculator

Ideally, I'd like to get rid of the expansion tank in the loft.

Assuming you want to retain the hot water cylinder, you will need a system boiler.

there is a possibility that the large copper hot water cylinder should be replaced

May be advisable; depends on how old it is, what insulation, if any it has, and how hard your water is.

If, as seems likely, we end up with a new boiler, what should we have changed to make the system more efficient?

We do not (at present) have any radiator valves on any radiators.

Presume you mean thermostatic valves (TRVs). They are a good idea - but make sure you use good ones e.g Danfoss, Drayton or Honeywell.
There should not be TRV on the rad where the room thermostat is located

Could we have a separate thermostat/valve to shut off heating to the top floor as it gets very warm up there whilst the bottom floor is distinctly chilly.

Fitting TRVs will help that or you can zone the system, provided the piping is suitable.

You should also update your controls, timer and thermostats as modern ones are more accurate and give greater flexibility. Some boiler have provision for weather compensation, which varies the boiler output to meet requirements according to the outside temperature.

 

[XrayDave]

Many thanks for that swift and comprehensive reply D_Hailsham.

I am intrigued as to your answer to my question "I hear that Worcester Bosch and Vaillant are the best condensing boilers to go for." as your reply was somewhat non-commital. In your opinion (as you seem to be knowlegable in this area, what would you recommend?

On the question of getting rid of the expansion tank in the loft, you say that I'd need a system boiler. As I understand it, both of my proposed boilers in my OP are system boilers. Do I not need some sort of expansion tank?

As far as the copper hot water tank goes, we have been in the property 13 years and the previous owner installed the central heating system around 15 years before that. I'm guessing therefore, that the tank is approx 28 years old. Certainly it does not have any of that hard yellow foam insulation on the outside, just a loose-fitting multi-segment cylinder jacket held in place by a couple of steel bands around the tank.

On the question of boiler output, both calculators take the same info as input, however one yields an output figure of around 15kW whilst the other gives a figure of 37.7kw The Ideal Minimiser FF80 appears to be around the 25kW mark in terms of output.

The Worcester Bosch Greenstar 30CDi (30kW) and Vaillant ecoTech plus 630 (or the 624/637) (outputs 30, 24 or 37kW respectively) seem to be in the right sort of "ball-park"?

Am I correct in thinking that the best match for my current boiler would be the Greenstar 30CDi or the ecoTech 630?

Any additional help here would be welcome.

Happy New Year

Dave

 

[D_Hailsham]

On the question of getting rid of the expansion tank in the loft, you say that I'd need a system boiler. As I understand it, both of my proposed boilers in my OP are system boilers. Do I not need some sort of expansion tank?

The Vaillant 637 is a system boiler; this type does not need an expansion tank in the loft, but you still retain the hot water cylinder, which need a cold water supply tank in the loft.

The WB 40CDi is a regular or heat only boiler; this still needs a feed and expansion tank as well as a hot water cylinder and associated feed tank.

If you want to get rid of both tanks in the loft you will have to go for a combi boiler. This is a system boiler with the added facility of providing hot water direct from the mains. The only problem with this is that the flow rate to your bath. shower etc depends on the mains flow. You can also have problems if you want to run hot water from more than one outlet at the same time,

If you want to convert the loft into a habitable room then the combi is the way to go, but note the problems mentioned above.

the copper hot water tank ... does not have any of that hard yellow foam insulation on the outside, just a loose-fitting multi-segment cylinder jacket held in place by a couple of steel bands around the tank.

Then it's worth replacing it. The heat loss through the loose jacket will be enormous compared to modern cylinders with integral jacket. YOu can now get high recovery cylinders which heat up much quicker, so you do not need such a large cylinder.

On the question of boiler output, both calculators take the same info as input, however one yields an output figure of around 15kW whilst the other gives a figure of 37.7kw

Then you have used one of them wrongly, as they are effectively the same calculator, but one is more user-friendly. I normally use the EST one, but it has been off-line recently.

Does the Sedbuk calculator give the higher result? If so it's because you have entered the original dimensions wrongly.

Page 1
Length and Width: The internal length and width of the entire house
(Length is the frontage, width is the depth)
Room height: Floor to ceiling height of the rooms (use the ground floor as that is usually the highest)

Page 2
External walls:
A detached house has two external walls lengthwise and two widthwise.
A semi detached and end terrace has two external walls lengthwise and one widthwise.
A mid terrace house has two external walls lengthwise only.

The rest is self-explanatory.

The Ideal Minimiser FF80 appears to be around the 25kW mark in terms of output.

You should not base the size of your new boiler on what is there now. For two reasons: boilers tended to be oversized in the past; the house may have changed - e.g insulation, double glazing etc. That's why I recommended the calculators.

Rerun both calculators and you should get results within a kW of each other. That's the size boiler you need. Alternatively, post all the relevant data and I will run it through the calculators.

Another thing worth doing is to estimate the heat output of all your radiators. You can use the Stelrad Elite Catalogue to do this. Post this info.

 

[XrayDave]

Thank you once again for your speedy & comprehensive reply.

Ideally, I'd like to get rid of the small expansion tank in the loft. It is rather in the way. It would be nice to get rid of the large cold water tank (header tank?) because the loft is well insulated and distinctly COLD when you get up there (which is, I guess, the way it should be)!

Will run both calculators & see what I come up with.

As far as counting rads goes, does a double rad count as 1 or 2? Thinking about it it should count as 2??

Incidentally, it was the EST calculator which gave the highest result!

Dave

 

[scatmanjohn]

You say the BG engineer says you need a new boiler.

Are you on Homecare?

If so then it is up to them to repair it. The only time that a boiler is not repairable is if the parts are obsolete.

However if that was my boiler it would have been skipped a long time ago

 

[XrayDave]

Hi Scatman,

Yes, we are on Homecare 300. I agree with you when you say that the boiler would have been skipped long ago! In the last 3 years (ie since the boiler was only 8 yrs old) we have had the heat exchanger replaced, condensate trap replaced and 2 instances of the boiler not lighting due to the build-up of Aluminium Oxide. This is in addition to two annual services (the boiler was due for its third in 3 yrs when it broke down).

BG are coming out to repair the boiler on Wednesday (I don't know why not Monday or Tuesday - who knows), but the boiler gave up the ghost last Wednesday (30th) so we will have been without a primary heating source for almost a week (and we are in the 21st Century - go figure)!

The engineer is also arranging for a planner (?) to talk to us about a new boiler (at least I think that is the plan as I arrived home just as he was leaving).

Can't see the sense of having the boiler repaired only to have it replaced shortly afterwards (other than we will have whole-house heating inbetween-times).

Dave

 

[XrayDave]

OK, I think that I've found the problem between the two calculations.

The sedbuk calculator gives the external wall area as 519.7 m² whereas the EST caculator gives the external wall area as 260.5 m²

The property is 9.6m long x 7.1m wide x 3 floors each 2.6m high

I make that: 260.5 m² - which agrees with the EST calculator, but is virtually half of the sedbuk cacluator's result.

sedbuk calculator says 20 kW (for a larger wall area??)

EST calculator says 38 kW

I'm rather confused

Dave

 

[D_Hailsham]

The sedbuk calculator gives the external wall area as 519.7 m² whereas the EST caculator gives the external wall area as 260.5 m²

The property is 9.6m long x 7.1m high???deep or wide x 3 floors each 2.6m high

You have entered the dimensions wrongly in the sedbuk calculator!

The first number is the length (9.6m)
The second number is the room height (2.4m)
The third number is the width (7.1m)

You have swapped the second and third figures, which is why the wall area is wrong.

It is also worth checking that the window area is correct as they just use an average.

 

[XrayDave]

Hi again,

Doh! I'd spotted that earlier (yesterday) but when I re-entered the figures this morning, input the values in the same order as the EST calculator.

Have put in the correct figures now into the sebuk calculator and at least the wall areas agree.

The boiler outputs still don't however. The sedbuk is now saying 18kW whereas the EST says 38kW - quite a difference.

Dave

 

[XrayDave]

Here is the input information:

sedbuk first:

EST:

Same values but different result??

Dave

 

[XrayDave]

UPDATE:

Think I've found out what's happening!

The numbers in the EST caculator don't add up! It seems that although I have changed some values, the older values are being retained. Presumably, some data is being retained in my browser cache!

For example, if you look at the section "Window Heat Loss", you will see the calculation:

(260.5 x 0.17) x 3.0 [which equals 132.9]

but the result is given as 567!

Similarly for "Wall Heat Loss", the calculation is given as:

(260.5 - (260.5 x 0.17)) x 0.45 [which equals 97.3]

but the result is given as 415

I have re-run the calculations - this time pressing the "Restart" button. I now get a value from EST of 15kW for the boiler, whereas sedbuk gives 18kW.

Better going with the higher value figure - ie 18kW?

dave

 

[D_Hailsham]

Just looking at the last frame says something is wrong!

8903 + 3854 + 2000 + 0 = 14757 not 37667!

Did you remember to press the Calculate button on each page before pressing Next. If you don't do this the old info is retained. I have just run through with your info and EST gives 15kW. Sedbuk gives 14.8. You can't get much closer than that.

I notice that the window area in Sedbuk is 88.352, about twice what I get (44.285). Have you entered this figure by hand? EST and Sedbuk use the same window factors (17% of wall area).

On radiators, I was suggesting you used the data in the Elite catalogue (link earlier) to find out how many kW your radiators produce. A double radiator does not produce twice the heat as a single.

It's worth finding out the rad output as it might have a bearing on the size of boiler and could affect how well your house heats up. Please use the link I gave and post the results.

As for boilers, have a look at the Remeha Avanta. You can get 15 and 18kW Heat only boilers or 18kW System boilers. Combis range from 24kW to 39kW.

 

[XrayDave]

Thank you once again D_Hailsham

I'd spotted that something was wrong - probably something to do with my browser cache.

When I clicked on the "Restart" button, the figures then made sense.

Looking at the radiators now.

Thanks also for the "heads up" on the Remeha Avanta and the link. I'll have a look at these shortly.

Kind regards

Dave

 

[Agile]

Every installer has his favourite boiler!

D Hailsham only reads about boilers because he is not registered to install them.

Tony