Flue Very Hot- Firebird

Cerco

I have a Firebird Super 90 with a Riello burner. It is in the utility room and I notice that the area around the flue is quite hot. There is some cracking in the plaster. The thermostat is set at 70 degrees.
It is due the annual service and I am wondering is there something I can get done inside the boiler to reduce heat loss to the flue? Is there some internal insulation which could be redone etc. ?

jimf

when you get your boiler serviced is it set up correctly using a flugas analyser

baffle condition wrong nozzle fuel pump pressure non obstructed flue can all have a bearing on the flugas temp

the fact you have the stat set to 70 would really only reflect on the water temp

if you have a flugas analyser printout from the last service have a look at what the flue temp was

personally I find older fb boilers can have high flugas temp without any obvious reason

Cerco

Thanks jimf for your reply.
Here are the temps from last service:

Flue : 126 C
Inlet: 12.6 C
Nett: 113.4 C

How do they look ?

Thanks

jimf

Cerco wrote: »

Thanks jimf for your reply.
Here are the temps from last service:

Flue : 126 C
Inlet: 12.6 C
Nett: 113.4 C

How do they look ?

Thanks

if im honest with you I would have to say your boiler was set up long before it was anyway near its operating temp

usually you would be expecting the above temp to be around 220/240

Cerco

Should I run the boiler for a couple of hours before the engineer calls or would that make it awkward for him?

jimf

no need to run it before service guy arrives

running up to the operating temp is something you have to be prepared to do this is 1 of the reasons a boiler service done properly should be taking in the region of 90 mins to complete

Cerco

Thanks jimf , that's great information. I know a little more now.

Thanks again,
Cerco

Wearb

jimf wrote: »

if im honest with you I would have to say your boiler was set up long before it was anyway near its operating temp

usually you would be expecting the above temp to be around 220/240

Or under fired, under sized boiler, contaminated sample or sample taken too far away from heat source.

Op What was O2 readings on that sample? Do you know how long the boiler was running for when sampled?

Anyway your flue should be capable of handling any normal high temperature IF sealed and installed properly.

Cerco

Thanks Wearb.
The O2 reading is % 7.7
CO2 : 9.8
CO2 pps: 22

I don't know how long it was running before samples taken.

Thanks.

jimf

Wearb wrote: »

Or under fired, under sized boiler, contaminated sample or sample taken too far away from heat source.

Op What was O2 readings on that sample? Do you know how long the boiler was running for when sampled?

Anyway your flue should be capable of handling any normal high temperature IF sealed and installed properly.

good points as well wearb

Wearb

Cerco wrote: »

Thanks Wearb.
The O2 reading is % 7.7
CO2 : 9.8
CO2 pps: 22

I don't know how long it was running before samples taken.

Thanks.

Not a very good setup. It may have been caused by a poor sample. But it could be lots of other things also. Service person needs to work out why he is not able to improve on those results.

Wearb

jimf wrote: »

good points as well wearb

Yes good points, but if I were to bet on it I would bet that your explanation is mostly the correct one.

Cerco

Thanks Wears and jimf. I have a contact for an engineer , who is recommended, so I will get him to service it.
I thought it might have been heat loss in the boiler but now I know that is not the issue

Thanks again.

jimf

Wearb wrote: »

Not a very good setup. It may have been caused by a poor sample. But it could be lots of other things also. Service person needs to work out why he is not able to improve on those results.

it could be one of the i have fga but i haven't a clue how to use it brigade as well :rolleyes::rolleyes:

Wearb

Cerco wrote: »

I thought it might have been heat loss in the boiler but now I know that is not the issue

Thanks again.

Well with the information given here, you cannot say that for certain either.

Perhaps you will let us know what your new service guy says about it.

Wearb

jimf wrote: »

it could be one of the i have fga but i haven't a clue how to use it brigade as well :rolleyes::rolleyes:

I have come across them. They service the way they did years ago. Then stick in the analyser and print off the results.

agusta

Cerco wrote: »

Thanks Wearb.
The O2 reading is % 7.7
CO2 : 9.8
CO2 pps: 22

I don't know how long it was running before samples taken.

Thanks.

What is the ratio figure on your printout?, You should see see three zeros after the decimal point,
Your last service guy didnt know how to set up the boiler with the analyser,your boiler is over aired which is blowing the flame out the flue too fast which would make the flue hotter than it should be.
What your looking for from next service guy
A/ oil pressure set to manufacturers instructions
B/nozzle as per manufacturers instructions for the output required
C/ 02- between 3-6
D/ Co2 between 11.2-12 [check manual for exact]
E/Flue temp 190-240 [check manual for exact]
f/Ratio-three zeros after the decimal point
g/ Co- as low as possible
d/X Air % 33 to 37 approx

Cerco

Thanks Agusta.
The CO/CO2 is 0.0002
Other readings are:

EFF (N). 94.1
Losses: 5.9
XAir % : 58.3

O2%. 7.7
CO2% 9.8
CO pp 22
PRS ?bar -2.04

Thanks for the guide readings. Useful reference.

jimf

Cerco wrote: »

Thanks Agusta.
The CO/CO2 is 0.0002
Other readings are:

EFF (N). 94.1
Losses: 5.9
XAir % : 58.3

O2%. 7.7
CO2% 9.8
CO pp 22
PRS ?bar -2.04

Thanks for the guide readings. Useful reference.

the more info you post cerco the more convinced i am who ever did
your boiler the last time hadn't a clue

Cerco

It was first time I used him, jimf. He was baffled by the tiger loop so I was a bit suspicious. Anyway I thought he could do the boiler itself and I was impressed when he drilled a hole and fitted a screw to measure the gases in the outlet.

I have learned a lot today and glad I asked the questions. Thanks for all the replies.

Wearb

Cerco wrote: »

It was first time I used him, jimf. He was baffled by the tiger loop so I was a bit suspicious. Anyway I thought he could do the boiler itself and I was impressed when he drilled a hole and fitted a screw to measure the gases in the outlet.

I have learned a lot today and glad I asked the questions. Thanks for all the replies.

Did he highlight any problems on the service report?

Cerco

There was no service report, just the ticket from the analyser.

jimf

your boiler is grossly overaired at 58% xa if this was brought down to in or around 35% xa it might bring the rest of the settings into more acceptable parameters then i would like to see what your fg temp would be reading once the boiler is up to operating temp

Cerco

Thanks jimf for all your replies.