Worcester G'Star 15 Ri Combustion Performance.

[arran197]

Hi people, not sure if this is in the right section on the forum or not. I have come across a few Worcester Ri boilers recently on the housing association contract I work on.

One I went to a few weeks ago had been switched off due to high CO by the service engineer. I adjusted the gas valve as per the MI and it was fine. I have been to another one today and the CO was so high I think it has damaged the oxygen cell in my Sprint v2.

I have taken the boiler apart and someone has been f***ing around with it. God knows what they have been doing. The inspection and access cover is missing and has been covered by some closure plate tape. So first thing is, I'm turning it off. So I tried turning it on and it fired, but when it went to low fan speed, it cut out. So I checked the inlet pressure, 20mb.

The CO was through the roof. Tried turning the adjustment screw, but I can't actually check the CO2 because it's going far too high. Checked the premix pipe/duct and it looks fine. I took the burner and baffles out, cleaned them and they looked fine. I even cleaned out the condense trap. I rang and spoke to Worcester, but they said it was the heat exchanger needed cleaning. I have left it turned off for the moment as it was 6.30 tonight by the time I left. I have ordered the inspection cover too, but can anyone else shed any light on to what might be the problem? Might it just be out of adjustment on the gas valve? It was a Sigma valve with the adjustment on the valve itself as opposed to the adjustment on the gas pipe.

Thanks in advance, Arran.

 

[EPH]

What's the negative fan pressure?

 

[mfgs]

It will cut out on low flame if the ratio isnt right. I got called to one a while back where someone had serviced it and adjusted the ratios wrong and the co2 level was too low on minimum setting causing it to lock out. They are sensitive to adjustment, try giving it about half a turn down on max before using your fga again.

 

[arran197]

The negative fan pressure was -6mb on full speed. I tried turning both up and down on the max adjustment (top right hand side of valve, 4mm allen key I think it takes), but it was still shocking.

 

[arran197]

Found out today it has had a gas valve changed, about 3 months ago and hasn't been working for a month and a half.

 

[mfgs]

That explains it then. The valves dont come already set up, you have to adjust them to the required settings when you fit them,

 

[arran197]

Well I don't know if that is the problem. But it seems a bit on the strange side. I just don't know which I would have to turn it to make it better, I tried increasing the co2 on max but it didn't make any difference. Tired to on minimum, but it was going out. I ran out of time in the end.

 

[mfgs]

What readings are you getting? Too high co2 and co, or too low?

 

[arran197]

I couldn't take a reading for co2, the co was so high I had to take my analyser out. It really was high, I'm talking 9500 ppm! My analyser has only just stabilised tonight! I think someone else has been out to it today, so I will try and get some details of what has been done to cure it. Hopefully I won't have to go back if it has been fixed now.

 

[mfgs]

Then it needs turning down, sounds like youve been turning it up. Give it 1 - 1 /2 turns down on max to start with and go from there. I have never heard of readings that high before. Im pretty sure its just the gas valve needs setting up, as I said before they dont come pre-set out of the box and I bet someone just put it in and didnt set the ratios.

 

[Destroyer2813]

Had one a couple of months ago on a 40cdi the auto airvent leaked and took out the gas valve and fan took a good half hour to get the set up right patience is the key small turns at a time and and give it time to adjust before you get twitchy fingures and wanna turn it more

 

[Boilerbud]

Hi Arran

Make sure you do not have fluing problem by removing cover so that fan can draw air from room then gas analyse and see what result you get with cover off. If analysis is close to normal with fan drawing air from room the boiler is drawing in products of combustion because of leaking product flue pipe.

Hope this might help as high CO is not always gas valve problem.

 

[RoryD]

Hi people, not sure if this is in the right section on the forum or not. I have come across a few Worcester Ri boilers recently on the housing association contract I work on.

One I went to a few weeks ago had been switched off due to high CO by the service engineer. I adjusted the gas valve as per the MI and it was fine. I have been to another one today and the CO was so high I think it has damaged the oxygen cell in my Sprint v2.

I have taken the boiler apart and someone has been f***ing around with it. God knows what they have been doing. The inspection and access cover is missing and has been covered by some closure plate tape. So first thing is, I'm turning it off. So I tried turning it on and it fired, but when it went to low fan speed, it cut out. So I checked the inlet pressure, 20mb.

The CO was through the roof. Tried turning the adjustment screw, but I can't actually check the CO2 because it's going far too high. Checked the premix pipe/duct and it looks fine. I took the burner and baffles out, cleaned them and they looked fine. I even cleaned out the condense trap. I rang and spoke to Worcester, but they said it was the heat exchanger needed cleaning. I have left it turned off for the moment as it was 6.30 tonight by the time I left. I have ordered the inspection cover too, but can anyone else shed any light on to what might be the problem? Might it just be out of adjustment on the gas valve? It was a Sigma valve with the adjustment on the valve itself as opposed to the adjustment on the gas pipe.

Thanks in advance, Arran.

Arran hope I'm not teaching you to suck eggs but has the mode switch been set correctly? Using a 2.5mm key adjust the RH adjuster (low rate)with red paint on to 9.8% +/- 0.2. For low rate use 4mm key behind brass housing to 9.2% +/- 0.2. If reading is unacceptable I believe you count how many turns until it closes and undo it 5 turns to try and fire it. after that one turn at a time.

 

[arran197]

TBH, I think you guys are right. But the ones I have come across before with poor readings have never been that high, leading me to believe there was something more drastically wrong than just the gas valve. If I come across it again, I will ring and ask Worcester where I should go from. I.E., if I turn the max key all the way to the right until it stops, where is the most likely point at which I can get a reading low enough to start fine adjustment! As you have said Rory.

 

[RoryD]

TBH, I think you guys are right. But the ones I have come across before with poor readings have never been that high, leading me to believe there was something more drastically wrong than just the gas valve. If I come across it again, I will ring and ask Worcester where I should go from. I.E., if I turn the max key all the way to the right until it stops, where is the most likely point at which I can get a reading low enough to start fine adjustment! As you have said Rory.

All the way to the right is normal; once to the left is max;and on further click to the left is min. Thinking overnight I would keep turning until there is a drop. On max rotate the allen key clockwise to drop (it's the opposite way on the min rate setting). If the seals' integrity is compromised on the heat exchanger or if it is dirty, then this will affect readings.

 

[arran197]

Seal was sound. So if you turn it all the way to the right? I might ring Worcester if I come across anything this bad again.

 

[RoryD]

Seal was sound. So if you turn it all the way to the right? I might ring Worcester if I come across anything this bad again.

Yes to the right is normal, but your adjustments are made at max and min, you turn it back to normal at the end. Mate you should be able to get the instructions online at worcester bosch.

 

[arran197]

Ye, it wasn't the adjusting method or the values I was struggling with, it was getting the values to a point where they could be analysed properly, or where to start from as they were so far out.

Co was so high my analyser was warning me after a few seconds in max mode and the boiler wouldn't stay on in min mode.

Sent from my X10i using Tapatalk

 

[RoryD]

Hi people, not sure if this is in the right section on the forum or not. I have come across a few Worcester Ri boilers recently on the housing association contract I work on.

One I went to a few weeks ago had been switched off due to high CO by the service engineer. I adjusted the gas valve as per the MI and it was fine. I have been to another one today and the CO was so high I think it has damaged the oxygen cell in my Sprint v2.

I have taken the boiler apart and someone has been f***ing around with it. God knows what they have been doing. The inspection and access cover is missing and has been covered by some closure plate tape. So first thing is, I'm turning it off. So I tried turning it on and it fired, but when it went to low fan speed, it cut out. So I checked the inlet pressure, 20mb.

The CO was through the roof. Tried turning the adjustment screw, but I can't actually check the CO2 because it's going far too high. Checked the premix pipe/duct and it looks fine. I took the burner and baffles out, cleaned them and they looked fine. I even cleaned out the condense trap. I rang and spoke to Worcester, but they said it was the heat exchanger needed cleaning. I have left it turned off for the moment as it was 6.30 tonight by the time I left. I have ordered the inspection cover too, but can anyone else shed any light on to what might be the problem? Might it just be out of adjustment on the gas valve? It was a Sigma valve with the adjustment on the valve itself as opposed to the adjustment on the gas pipe.

Thanks in advance, Arran.

I presume the inspection hatch is that little one at the bottom of the heat exchanger. Mate it's pointless trying to adjust anything whilst it's in that condition. As Worcester say, clean the heat exchanger (good luck) and remember it's compulsory to change all disturbed seals. Should be adjustable after that mate

 

[GasmanxxxR1]

Yep, remeber you need to change the gasket if you clean the heat exchanger

 

[arran197]

I presume the inspection hatch is that little one at the bottom of the heat exchanger. Mate it's pointless trying to adjust anything whilst it's in that condition. As Worcester say, clean the heat exchanger (good luck) and remember it's compulsory to change all disturbed seals. Should be adjustable after that mate

No, the cover is the one on the top of the case, which allows you to access the neat exchanger with the tool to remove the baffles. Not 100% what the outcome of this was, I need to check and find out as the lead engineer went out to look at it after me. I think the the gas valve just needed adjusting, I have been setting up some JNRs over the past few days and even the slightest movement out of the allowed co2 range and the co goes really high.