Firebird Condensing Boiler

John.G

Few photos here from a 26/35kw, the baffles are damaged as shown, this boiler spends most days on UFH with consequent low return temperatures of ~ 35/45C, is this indicative of low temperature corrosion?, (baffle positions as in boiler). Service person thought it was due to high temperatures and derated the boiler from 35kw to 26kw.

Also condensate trap queries.

Is this trap positioned correctly?, ie should it be vertical?

Does it have a float or is it simply a dip tube?.

Is the condensate drain baffle made of stainless?.

I read on here years ago where it said that the condensate drain is positioned between the two heat exchangers?, looking at the schematic it seems to be on the bottom where one might expect it?.

The boiler (UK) was installed in 2019 and this baffle damage occured within one year.

Firebird Condensate Trap1.jpeg

Firebird Condensate Trap2.jpeg

Firebird Baffles.jpeg

Wearb

As for for firing rate, its almost always desirable to fire those at its lowest allowable rate.

I usually find that damage on the top plate, but have come across it on other baffles. That one may have been rotated on a previous service.

The trap outlet looks high and forcing the plastic pipe against the boiler casing, but that could be the photo angle. The melted pipe isn't unusual if the trap runs dry. That shouldn't happen with the return temps you mentioned and flue pointing upwards. Yes horizontal as in your image from MI.

Edit: Just a dip tube. Drain baffle made of stainless steel and positioned as shown. Seems to be there to stop crud getting into and blocking condensate outlet. Some times the trap isn't screwed properly to the boiler outlet or sealing washer missing or misaligned. Then the condensate trap doesnt fill properly amd allows hot gasses to flow through to damage the plastic pipe.

jimf

usually with these boilers when you come across the top 2 baffles damaged in this way overairing plays a big part

most likely boiler wasnt commissioned after install

agree 100% the harder a he boiler is made work the better the eff

as for the trap such issues could be caused by short cycling as the boiler will not be in condensing mode and the trap will dry out

blocked trap or poor flow from the pipe could also cause excess heat

regular servicing and baffle rotation will also help this boiler looks like it has never been open before

John.G

Is this damage a indication of high temperature? these are the bottom two and as far as I know hadn't been switched around and if so since the burner fires downwards why would they be damaged in this manner?.

jimf

if they are the bottom 2 john that and the state of the condensate hose would suggest a blockage from the bottom of the boiler

where is that pipe discharging

and does it have a fall from the outside of the boiler case

i have often come across the pipe rising sharply outside the case

jimf

can your pour water into the flu and see does the water discharge through the turbulator holes

John.G

Thanks Jim, I can arrange those tests (boiler in UK) and ask about the pipe discharge and water through the turbulator holes, is this damage (still) a indication of NOT cold end corrosion or whatever its called?.

jimf

i would still be looking at the discharge from boiler and condensate as a first port of call

hard to say really without seeing for yourself the scaling on the baffles is more common that you might think

the little serrated edges on the baffles is where the heat escapes plus your forcing heat down when it naturally wants to rise

any dirt build up is naturally going to cause the boiler to run above manf recommended temp

i do know we have a taxi man who posts here from time to time swears by bending the baffle corners to allow faster heat dispersion

John.G

Thanks again, would the flue gas temperature tell anything (what would you expect) and can the temperature after the primary Hx be taken and if so, what would you expect to see here and where can the probe be inserted.

jimf

depends on what boiler re the temp

enviromax temp up to 90 at flue

silverpac up to 130 at flue

overall fga will tell us a bit more if you could get your hands on same

i have an idea re flugas temp after primary but would not be happy to advise

John.G

Condensate waste pipe seems to have been the (a) big big problem, despite home owner reminding installer several times re 1:40 minimum fall required he insisted in running the pipe vertically upwards resulting in lots of water in the bottom of the boiler casing!.

Boiler: Environmex C35

Commissioning numbers.

Boiler is set up to burn light fuel oil (is this allowed??)

Air setting: 2.5

CO2 11.91% (at ~ 9C ambient)

O2 is 4.something, possibly 4.9%

Oil pump pressure: 14.0 Bar

Burner: Riello 2.2R 35-54kw

0.65 80S nozzle.

Flue temperature: 95.2C.

Wearb

I would send that tech packing until he gets more supervised experience. Did he not even read the manual 😏

Nobody in these islands call either of the heating oils light oil. Is it kerosene or diesel. Pump pressure suggests diesel which is not allowed. Light oil is the product that you choose on the analyser, because the calorific value of both fuels are close enough not to matter at domestic levels.

If that's burning diesel (and it looks like it), then its at is maximum output. Kerosene should not be burned at those pressures.

John.G

Yes, informed ite Diesel, the boiler is located in NZ.

Wearb

https://www.boards.ie/discussion/comment/119345370#Comment_119345370

"New Zealand"

I'd leave it a few days before getting a proper Tech to set it up properly....they'll be feeling raw for a few days 🤣🤣🤣 🏉🏈

Wearb

The biggest danger with diesel on those is the flue. Maybe a plume kit would mitigate it somewhat, but I never deviate too much from MIs. Not worth it. You're on your own if it goes wrong.

In any case that needs derating to prolong the boiler.

A .85 80 es at 7.5/8 bar on kerosene would be about right for that.

They're not a bad boiler if set up properly and serviced annually. They will not last if neglected. Maybe also show customer how to clean the cell ever 6 months.

John.G

The boiler was downrated (because they thought it was over heating at 35kw) to 26kw, burner was changed to a Riello RDB 2.2 26kw - 41Jx with a 26 kw rated nozzle.

Wearb

So what's the setup now?

jimf

the boiler could have been downrated without changing the burner

i think they really need somebody that understand how to set up a burner properly

you could contact firebird direct john for the gas oil settings i dont have them

i dont have any he boilers running on gas oil

John.G

I'm only replying/ trying g to help someone from NZ posting on a GB website.

How do any of these boilers achieve any form of condensing with flue gas temperatures of 90C or even higher, the flue gas temperature has to be 50C or less to even begin to condense. My neighbour has a HE Warmflow and I have seen one of his FGAs showing something like 118C and I would be fairly confidant that the boiler return certainly wouldn't be greater than 60C, what accounts for a dT of 58C.

Wearb

https://www.boards.ie/discussion/comment/119346604#Comment_119346604

The flue gasses are hitting the secondary heat exchanger while still carrying a lot of water vapour. Some of this is condensing of the cool (relativity speaking) secondary heat exchanger. Of course not ever molecule is hitting the secondary hx and therefore the flue temperature is going to be above the water temperature of the secondary hx.

I am mostly replying like this for the benefit of -perhaps- some other readers, as I know that you understand most of this better than most John.