Worcester 24i rsf???

[macka09]

Hi guys. Do any of you have much experience with these boilers as I’m due to service a couple tomorrow and any advice would be great? I’m wondering why the co2 readings are variable depending on flue length? Also I can’t see a way of getting a minimum reading on the fga? I can’t seem to see a reading for gas inlet pressure either? Sorry for being a pain.

 

[Deleted member 32524]

If it's the one I am thinking g of take the lead off gas valve to get minimum readings. Inlet 20mb. Burner pressure readings on data plate.

 

[EvilDrPorkChop]

The RSF is the really old one with the grey front I think. Gas Rate, Inlet Pressure and CO2 readings, if all those are correct there's no need to adjust burner pressures. Should be less than 100ppm (in my experience on these), and ratio less than 0.004. C02 is usually around 5-6 from memory

 

[macka09]

The RSF is the really old one with the grey front I think. Gas Rate, Inlet Pressure and CO2 readings, if all those are correct there's no need to adjust burner pressures. Should be less than 100ppm (in my experience on these), and ratio less than 0.004. C02 is usually around 5-6 from memory

Thanks for this. Is there a way of getting it in to min and max??
These aren’t the boilers with the awful plastic screws for the case are they?

 

[Deleted member 32524]

Max, bath tap fully open. Min, remove the wire on the gas valve.

 

[Millsy 82]

The RSF is the really old one with the grey front I think. Gas Rate, Inlet Pressure and CO2 readings, if all those are correct there's no need to adjust burner pressures. Should be less than 100ppm (in my experience on these), and ratio less than 0.004. C02 is usually around 5-6 from memory

Sorry but I disagree. You set the burner pressure on them to what is stated on the data badge.

Macka
These boilers were out before using an analyser was common practice so there is no manufacturers specific readings your looking for so it goes with the standard 0.0040 and under 350ppm co.

Realistically you will have under about 20ppm.

Just go old school on the boiler strip it clean it leave running for 5 minutes to burn off any loose dust. To set on low there may be a black screw on the back of the pcb to adjust min/ max

 

[Harvest Fields]

I would complete a full strip and clean and FGA in hot water mode. Are these the ones with the little black circle that you can adjust on the back of the PCB?

 

[Millsy 82]

I would complete a full strip and clean and FGA in hot water mode. Are these the ones with the little black circle that you can adjust on the back of the PCB?

I know the cdi's have the little black screw on the back cant remember on these. They are the older ones so it may just be remove the lead from the gas valve. It's been a while since I worked in one.

 

[EvilDrPorkChop]

Sorry but I disagree. You set the burner pressure on them to what is stated on the data badge.

Sorry but I disagree with that.

If you’re setting burner pressures without checking the gas rate first then your wrong. You could be setting a burner pressure to a wrongly sized injector/blocked injector, in which case the pressure will be incorrect and thus causing the Gas rate to be wrong.

If you’re inlet pressure is correct, and your gas rate is correct then your burner pressure has to be correct. If this was wrong one of the other two would be incorrect.

 

[Millsy 82]

Sorry but I disagree with that.

If you’re setting burner pressures without checking the gas rate first then your wrong. You could be setting a burner pressure to a wrongly sized injector/blocked injector, in which case the pressure will be incorrect and thus causing the Gas rate to be wrong.

If you’re inlet pressure is correct, and your gas rate is correct then your burner pressure has to be correct. If this was wrong one of the other two would be incorrect.

I would phone Worcester and gas safe to double check that if I was you. What you have described was what to do on a newer boiler not a boiler with a burner bar. When these boilers were around analysers were virtually unheard of unless you worked on commercial or maybe the likes of British gas but it was not common practice so it was done by burner pressure, gas rate flame picture clean out check flue ventilation etc job done.

A blocked injector or a the wrong injector is another problem that you would pick up by doing the boiler service correctly.

 

[EvilDrPorkChop]

I would phone Worcester and gas safe to double check that if I was you. What you have described was what to do on a newer boiler not a boiler with a burner bar. When these boilers were around analysers were virtually unheard of unless you worked on commercial or maybe the likes of British gas but it was not common practice so it was done by burner pressure, gas rate flame picture clean out check flue ventilation etc job done.

A blocked injector or a the wrong injector is another problem that you would pick up by doing the boiler service correctly.

I wasn’t saying not to do a strip down service, the OPs question was about CO2 readings if you’d read it correctly before jumping to conclusions. He was asking about readings not how to complete the service.

A full strip down service should be completed on any flat bed burner boiler, I’m not saying that shouldn’t be done.

Also you wouldn’t always pick up on an incorrectly sized injector; if there’s no manufactures instructions or a previous installer has incorrectly cleaned one out wouldn’t always be obvious. My point still stands, if gas rate and inlet is correct your burner pressure will be right.

 

[Millsy 82]

So dont check it then. I couldn't care less to be honest I will do right you can do it however you like but if you are going to tell someone to do something then either

Tell them the correct procedure

Or

Dont say anything especially dont tell them not to check something they should be checking.

Somebody may of changed the injector altered the pressure so the gas rate and ratio are correct but boiler wont work as it should because let's be honest if you gas rate it and it comes out 10% lower than it should you think it's ok but you could get it closer to what it should be.

 

[EvilDrPorkChop]

So dont check it then. I couldn't care less to be honest I will do right you can do it however you like but if you are going to tell someone to do something then either

Tell them the correct procedure

Or

Dont say anything especially dont tell them not to check something they should be checking.

Somebody may of changed the injector altered the pressure so the gas rate and ratio are correct but boiler wont work as it should because let's be honest if you gas rate it and it comes out 10% lower than it should you think it's ok but you could get it closer to what it should be.

That’s the best part though isn’t it; I never said don’t check it.

It’s simple laws, I’ve not given any incorrect information at all. If your inlet pressure is right, and the gas rate is right then your burner pressure has to be right.

Always check the GR first. If incorrect then proceed to investigate why.

 

[Millsy 82]

It's simple law that if you allow something through at a higher pressure through a smaller hole you could still use the same amount of gas. Same the other way round if you restrict the pressure then push it through a larger opening you would still have the same.

If it was rigid all oil 21kw oil boilers would use the same nozzle at the same pressure but they dont some use bigger with lower and others use smaller with higher pressure all still with the same usage.

 

[EvilDrPorkChop]

It's simple law that if you allow something through at a higher pressure through a smaller hole you could still use the same amount of gas. Same the other way round if you restrict the pressure then push it through a larger opening you would still have the same.

If it was rigid all oil 21kw oil boilers would use the same nozzle at the same pressure but they dont some use bigger with lower and others use smaller with higher pressure all still with the same usage.

You don’t make any sense? That’s what I was saying; hence why you’d do a gas rate.

If your injector size is wrong (blocked, made bigger, wrong injector) but you’ve adjusted the burner pressure setting to be correct then the gas rate is going to be incorrect.

Obviously, from that point you’d proceed to investigation why.

But my point still stands; if you gas rate the appliance first and it’s correct then your burner pressure will be spot on.

 

[Millsy 82]

A gas rate can be 10% lower or 5% higher than required by the boiler so 21.6kw to 25.2kw so you could have a 24kw running at 22kw and that is then correct? You will have poor hot water performance that is why you set the burner pressure to what is stated by the manufacturer you then check the gas rate to see if it is what you require.

As an example to make sense of what I said. A Worcester 24i is if I remember correctly 14mbar a vaillant 10mb a vokera 9.2 (they are only rough guesses from memory) so that's 3 different burner pressures giving out 24kw so in theory you could put injectors from 1 boiler in another and drop the pressure or increase the pressure to suit. So you go in set the burner pressure first then use a gas rate to check it is using the correct amount of gas.

Then you have range rated appliances you set the burner pressure to the maximum do your gas rate and analyser checks then drop them back down to the kw required and recheck the co/co2 ratio.

 

[RoryD]

Download the M.I's , they are on the Worcester site and read them. Testing at max & Min has been outlined. Test at what the data badge says (if attainable, if not AR) then put it back to where it was. You can adjust at the Gas valve after pulling off little plastic cover. Use allen keys large (outer) and small (inner).

 

[macka09]

It was all ok mate. I did wonder though if the max burner pressure was fluctuating what would be the cause of that if the inlet pressure is ok? Faulty gas valve?