Worcester 350 overheating! But is it really? Not thermostat
- Thread starter nv_london
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Have any of your various repair men checked the setup of the gas valve?
From the history of your X400 treatment it does rather sound as if you may have dislodged system dirt which is now partially blocking the boilers waterways.
Does anyone know if the W-B fixed price repairs include boiler blockages from dirt?
Tony
From the history of your X400 treatment it does rather sound as if you may have dislodged system dirt which is now partially blocking the boilers waterways.
Does anyone know if the W-B fixed price repairs include boiler blockages from dirt?
Tony
Before investigating overheating its necessary to check ad confirm that the heat input to the boiler is correct!
If a 24 kW boiler is set to take 36 kW then the chances are that it will overheat !!!
A wrongly set minimum gas rate is a very common cause of overheating as the control modulates the boiler down but the heat input does not reduce accordingly.
I once saw a new boiler where the installer had fiddled with the gas valve so the minimum was at same setting as the maximum!
Tony
If a 24 kW boiler is set to take 36 kW then the chances are that it will overheat !!!
A wrongly set minimum gas rate is a very common cause of overheating as the control modulates the boiler down but the heat input does not reduce accordingly.
I once saw a new boiler where the installer had fiddled with the gas valve so the minimum was at same setting as the maximum!
Tony
It can be done at the boiler with equipment.
OR it can be checked by timing the small 1 cu ft dial on an older gas meter or take two meter readings 2 min apart on a digital meter.
That would need to be done at full power on hot water and also on minimum power which is a little more difficult to set but could be done by turning down the hot water flow to a stable condition JUST higher than when the flame goes out. Or on many boilers by pulling off one modulating coil connection.
Post the results here and someone will decode it for you or you might find the answers on the internet, better here though so we can interpret then and assimilate them with your faults.
Tony
OR it can be checked by timing the small 1 cu ft dial on an older gas meter or take two meter readings 2 min apart on a digital meter.
That would need to be done at full power on hot water and also on minimum power which is a little more difficult to set but could be done by turning down the hot water flow to a stable condition JUST higher than when the flame goes out. Or on many boilers by pulling off one modulating coil connection.
Post the results here and someone will decode it for you or you might find the answers on the internet, better here though so we can interpret then and assimilate them with your faults.
Tony
Hi John.
Sounds to me as though you have a flow problem through the heat exchanger, adding the x400 was helping clean though not enough. I also suspect heating temp control.
The stat tripping is highlighting the fact boiler is exceeding 100'c, two places where parcial blockage may be, HE or the central heating return manifold, and third pump (just becuase its turning dont mean its circulating properly).
You need the best of your repair men to attend when boiler is off, for him to check max's and min settings, as pointed out by Tony, and with boiler running observe what is happening as it goes to fail, he will need thermometer on flow and return at this point.
System pressure sensor will also shut the boiler off though not trip the high limit.
At this point I lean towards partial blockage but temp sensor not bringing flame down is a very very strong possible, your repair man will be able to identify this.
Sounds to me as though you have a flow problem through the heat exchanger, adding the x400 was helping clean though not enough. I also suspect heating temp control.
The stat tripping is highlighting the fact boiler is exceeding 100'c, two places where parcial blockage may be, HE or the central heating return manifold, and third pump (just becuase its turning dont mean its circulating properly).
You need the best of your repair men to attend when boiler is off, for him to check max's and min settings, as pointed out by Tony, and with boiler running observe what is happening as it goes to fail, he will need thermometer on flow and return at this point.
System pressure sensor will also shut the boiler off though not trip the high limit.
At this point I lean towards partial blockage but temp sensor not bringing flame down is a very very strong possible, your repair man will be able to identify this.
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