Biasi 24s on the way out - new boiler? (Teesside area)

[richw]

Hi all,

I moved into this 3-bed semi a year ago. There is a Biasi 24s combi boiler (fitted early 2002). The central heating pipework is a mix of 10 and 22mm and the rads are large 1970s panels. Last November, an emergency fixed price repair from Biasi resulted in a new gas valve. I'm noticing more and more that things are not quite right. The fan has started whining (bearings?) and when the shower is on, the boiler has a habit of cycling off/on. The person who swapped the gas valve assures me the min/max pressure is set up correctly, and I saw him do it.

The other day, following a bath, it shut down and I had to press the reset button. I had a peek inside and spotted some pipes with evidence of leaks/scale, and a rather perished rubber seal. On the heating side, the rads all get belting hot, but I could do with an extra one in the kitchen.

I'm thinking that a new fan, seals, fixing of leak, probably cleaning/replacement of heat exchanger(s)... all sounds like throwing a lot of money at a 10 year old cheapo combi. Does that make sense? And I want something reliable, which I'd rather see to now, than in a breakdown and/or winter!

After having read this forum a lot, I'm keen on the Atmos/Intergas (what's the deal here - are they the same?) or maybe a Veissman. I've seen too many negative comments recently on Worcester-Bosch or Vaillant. Many people round here seem to get Baxis, but I get the impression they are nothing special...

Are there any local (Teesside area) fitters on here who would be interested in such a job? I guess I need to get one or two people round to have a look?

Anything I should look our for, or ask for specifically? Are magnetic filters a good idea? Any to avoid? Do I have to have a powerflush, or is a month of x400 good enough?


Sorry for the length, but I'd appreciate any feedback.


Cheers,
Richard.

 

[richw]

No-one?

I appreciate I may have rambled a bit, but even any quick pointers would be appreciated!

Atmos/Intergas a good idea? Magnaclean or similar? Biasi worth throwing money at?

 

[loafer]

The sum cost of the possible replacement parts on a boiler, if purchased separately amount to much more than the cost of a new boiler.... not to mention the cost of labour. Basic analogy is this. If it was car that failed an MOT a legal document that you must have in order to ensure safety/roadworthiness and legal compliance and the fail list ran to several pages, it may be better off scrapping and gerrin another car. Problem is you cant get 2nd hand boilers Unless someone in Rotherham, a landlord asked you to replace a boiler that he supplied that was a Vaillant eco-tec 28 with flue but curiously no dhw elbow and no hanging bracket.... Curiously Keir put these in sheffield council houses I made my excuses and left

It may be beyond the rules of the forum or unreasonable to expect people on here to make specific recommendations but the manufacturers that you mentioned are in the "ballpark".

Dont forget scale inhibitor to add to your wish list should your location require 1 and diff by-pass valves if specifically required by maufacturers to meet minimum requirements vis-a-vis guarantee conditions.

I have no qualms with the manufacturer who has a bunny wabbit on the boilers badge... but where I get em from; the md puts a kick up the bootay of the bunny wabbit badged boilers and he gets any probz sorted out PDQ. Thankfully this is a rareity.

 

[richw]

Thanks. I get what you mean about the sum of the parts. Also, I'd forgotten that the pressure gauge doesn't work, and the PRV weeps a bit when it's freshly filled (but stops after a few hours!).

The guy who repaired the Biasi for me recommended a Vaillant (for big money) or another Biasi, as he said they are actually very reliable. I've been reading this forum for ages, and couldn't quite agree with him. But it's interesting that you say they are not so bad!

Good point on the bypass and inhibitor - noted.

I am edging towards something new, but I want it to be done well and have piece of mind.

 

[Agile]

Your 24S Biasi is one of the most reliable boilers ever made.

Its 10 years old and not surprisingly the fan having been running all this time in a hot environment is getting a little worn. A replacement is about £130.

The plate HE is rather blocked with sludge. A good DIYer can clean them.

I would charge about £270 to replace the fan and clean the plate HE in my areas. Thats a lot less than £1750 for a new boiler!

The parts are all still available and properly looked after will probably still be working in another 10 years time.

Tony

 

[richw]

Hmm, interesting. The guy who replaced the gas valve said they were generally reliable and he didn't get many call-outs for them at all. My previous house had a Ravenheat, and the Biasi has been great compared to that! I do worry about the extra complexity in the more modern boilers, and wonder how reliable they really would be.

Hmm... if I could get all my issues sorted for £300, and there could be some sort of warranty, then that would be tempting. I did even ponder just putting some 3-in-1 on the fan. On the plate HE, does that involve removing it and soaking in something strong? Would I really have sludge if the rads all get so nicely hot? (or can sludge exist only on the HW part, so the plate HE, and not really on the CH side?)

But there are other issues: the leak, the dodgy combustion chamber seal, the PRV which sometimes drips, and the pressure gauge not working.

Bah... it's never simple! I guess one of you guys would use your own time and ability to make-do-and-mend, but for a DIY-er who doesn't want to risk no CH/HW with the missus and a baby...

Thanks for your comments. I appreciate them.

 

[Agile]

That Biasi PCB is single sided and the most advanced chip is an LM324 single power supply rail and NPN transistor quad OP-Amp from 1974 !

Very tried and tested!

Current PCBs are microprocessor controlled and that enables possible hardware and software errors. Both fairly rare but more likely to prevent any boiler operation at all.

At least the old Biasi PCB usually only partly fails and still maintains some operation. All the CH to DHW switching is by hydraulic operations and not electronics. Rather simple compared with the current Hall effect sensors and moving magnets.

Tony

 

[DP]

LM324 single power supply rail and NPN transistor quad OP-Amp from 1974 !

Tony, how do you know it is NPN transistor op amp? Why not PNP? A transistor is a package with three or 4 wires or a lump of plastic for surface mounting. A chip is what a LM324 is that comprises a silicon chip that is layered with doped silicon 'wafers' to emulate transistors (bot PNP and NPN), diodes, resistors and capacitors but no discreet components soldered onto the chip- that is done outside.

 

[Agile]

Look up the original design parameters Danny!

 

[richw]

Hmm... I do like the sound of simple! Are there any black-and-white tests I can do myself to determine:

a) if the fan is dying (it whines and gently tapping the flue pipe stops it briefly)

b) how to verify the plate HE for blockages

If the plate HE is blocked, what's an easy option to fix?

 

[Agile]

Fan needs RGI to fit. Best wait until it fails.

Plate blockage results in temp gauge going to 70-90 c on DHW. It can be cleaned.

Tony

 

[richw]

Thanks. So if I can get some sort of temp gauge onto the DHW output, see how stable it is, then that's my answer? Do I need to remove it and soak it in a concentrated cleaner for a few hours? Or can I cheat and stick some X400 in the CH system?

Presumably the CH (primary HE) and HW (plate HE) are actually the same water circuit, so surely if the plate HE is sludged, I'd see evidence of sludge in the rads? (cold bottoms)

 

[DP]

Look up the original design parameters Danny!

Tony, I just did. Page 2 of http://www.ti.com/lit/ds/snosc16b/snosc16b.pdf
shows both PNP and NPN.