Riello RDB 1 at the limit of settings

[DJS55]

Hi Folks

I just installed a new Riello RDB 1 replacing a older G5 BF, its in a grant 50-90 Balanced Flue (late 90s, utility model). I am near the end of the air adjustment to achieve figures which are within tolerance e.g 02% 4.7, CO ppm 12, CO2% 12, Flue gas temp 226, excess air 29% and Eff gross at 84%. There are no restrictions to air intake etc and I am of the opinion the RDB 1 is at the upper end of its capability hence near wide open air adjustment (6 on the scale to achieve the above figures) any thoughts?
Cheers

 

[Dotty]

What nozzle?

 

[DJS55]

0.65 x 60s at 8 Bar

 

[lame plumber]

well queried that man 🙂

 

[DJS55]

.65 x 60s again in scope for the older model and set at 8 bar

 

[Dotty]

Drop it down to 0.60.

 

[Killy Bing]

Is it the old euroflame model?
if memory serves
have you had it apart and checked the top baffle position?
It goes to the right or left depending on what kw setting you want to achieve.
That guess that effects your readings but i haven't had to check that.

also the length of the new burners blast tube can do it.

actually....i cant remember them being set up on the tech sheet for a .65 nozzle

 

[Dotty]

Next question was going to be baffles.

 

[Killy Bing]

Next question was going to be baffles.

sorry 😉
*rubs toes better*

dj did you replace the nozzle and set the pressure like for like?

 

[kimbo]

Settings for this boiler with an rdb are 60/60eh nozzle with 7bar pressure and an ld2 blast tube or 60/60eh 8.5bar pressure with an ld3 blast tube and co2 at 11.5 for both

 

[DJS55]

Drop it down to 0.60.

Thanks and can do and that model will also handle .75 x 60s at 7 bar

 

[DJS55]

Thanks and i am fitting new baffles and will check the location and if you do have data on which side that would be ideal. The blast tube is 7 mm longer that the old Riello G5 which was removed. I have the spec sheet re nozzles and can explore.

 

[DJS55]

Thanks and I have the spec sheet for the older model Euroflame pre EH nozzles, The RDB 1 was the Grant suggested replacement and i am on the ld2 blast tube. I am replacing the baffles as they are in poor shape and following this i will explore and the suggestions are welcomed.

Worst case scenario i can live with the figures but always fighting for perfection!

 

[SimonG]

Bin the spec sheets. They are based on a bench mounted boiler in a lab.

 

[Bunker]

Out of interest, why didn't you just stick a new G5 in?

 

[SimonG]

I always have a mectron kicking around. Must be the burner I have the least issues with tho.

 

[Dotty]

Out of interest, why didn't you just stick a new G5 in?

Was wondering that myself.

 

[kimbo]

Bin the spec sheets. They are based on a bench mounted boiler in a lab.

For the more experienced engineer I would agree but there are a lot of inexperienced engineers out there that need somewhere as a starting point when they are in trouble and havent got access to the wealth of knowledge found on here.

 

[DJS55]

Was wondering that myself.

Couldn't get one over the hols and the RDB 1 should suffice as its fitted in the later euroflame models with no physical boiler changes

 

[DJS55]

My comparisons on the CO2, excess air etc are binge made from settings achieved across a range installations as opposed to being based solely on specs in ideal conditions. However working within tolerance is key and outside of this, the inquiring mind will ask why.

As a recap I am comfortable with the figures achieved on my set up but getting near the top end of the air adjust was a tad odd to achieve the posted results.

In terms of experience I was coming behind two guys with 10- 15 years exp each (stickers on the front panel each year) and what a mess it was in every respect.

In terms of the RDB 1 it is fitted in the later Euroflame model with no physical boiler changes e.g baffles etc are identical to the earlier model.

I have a theory which I will test out when I go back to install the new baffles. Following that i will post my results as an update.

This is an excellent forum and thanks to everyone for the input and any other insights are welcomed

 

[Bunker]

I must say i welcome your input, nice rational engineer talk.
I would be hesitant to leave it at 12% - you may well go back to a sooty boiler before long. Id be as above, dropping the nozzle or the oil pressure.

Looking forward to hearing your updates.

 

[Roger Welton]

IIRC the RDB's fitted to the grants are specced slightly different to the 'off the shelf' variaty, I want to say they have a different fan scroll, and the baffle plate between the fan chamber and the rear of the nozzle chamber is different also.

 

[Dotty]

That the Oz model Rog?

 

[Roger Welton]

It is mate 🙂

 

[keltoyboy]

Had similar today with an rdb1 in a grant combi...... nozzle .75. 60 eh and air wide open and still 12%co2...... can't downrate as all output needed (and more)

 

[kimbo]

Diid you disconnect air snorkel and test in case flue seals are lesking

 

[Bunker]

Had similar today with an rdb1 in a grant combi...... nozzle .75. 60 eh and air wide open and still 12%co2...... can't downrate as all output needed (and more)

First thing with the Grant combi is to check the fan housing, probably full of water 🙂

 

[Roger Welton]

First thing with the Grant combi is to check the fan housing, probably full of water 🙂

Whenever that has happened with me it has ended up blowing the pcb.

 

[WHPES]

Had a similar problem once and found it was the filter in the analyser soaked in condensation when doing an external boiler set up in sub zero conditions.

Check / try adjusting distances between nozzle and flame spreader of the blast tube.

 

[DJS55]

As an update to the original post: The Co2 now reads 11.6% Flue temp 180 and excess air around 39%. Air adjustment is now in the range where i expected it, as opposted to the end of the travel and all is well!

Issue there was a restriction in the air intake and even though I could see day light when I first checked it; it was enough to cause the problem i.e more adjustment on the Burner to acheive the air flow required. New air intake fitted, a safe appliance and a happy customer.

 

[keltoyboy]

was the slide not opening fully!!!!

 

[Lou]

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