you can get this fault if the lockshield vlv is not fully open or the pipework feeding the radiator is too small/blocked 
Replacement radiator is colder at bottom than it is at top.
- Thread starter fluff29
- Start date
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no, the dark pipe didn't help but the picture did. and the pipe is 133 not 130, no wonder I couldn't find it on your diagram.
Found the pipe, coming out of the heat exchanger.
After 10 minutes, this pipe was 27.9, the return pipe underneath the boiler was 27.9.
hope this helps.
fluff
Found the pipe, coming out of the heat exchanger.
After 10 minutes, this pipe was 27.9, the return pipe underneath the boiler was 27.9.
hope this helps.
fluff
Fluff, thanks for posting the results.
Run the boiler in HW mode (preferably at the bath) with tap fully open. When water gets hot, take temperature readings at red and pink pipes. Now we can look to see if HW works OK. Take a temp reading of cold water and then hot. Also collect water over 15 seconds and post findings.
Looking at your figures- after 24 minutes 72/41 with hot tap on a tricle- there is no gurantee the valve has 'moved' as these valves have a 'bleed' path that will allow a small amount of water flow before the diverter will start to move. Also, if the valve is passing anyway, water at tap will pick up heat.
With tap closed, after 24 minutes, the temperature is 74/27 indicating you have a blockage towards the rads.
Run the boiler in HW mode (preferably at the bath) with tap fully open. When water gets hot, take temperature readings at red and pink pipes. Now we can look to see if HW works OK. Take a temp reading of cold water and then hot. Also collect water over 15 seconds and post findings.
Looking at your figures- after 24 minutes 72/41 with hot tap on a tricle- there is no gurantee the valve has 'moved' as these valves have a 'bleed' path that will allow a small amount of water flow before the diverter will start to move. Also, if the valve is passing anyway, water at tap will pick up heat.
With tap closed, after 24 minutes, the temperature is 74/27 indicating you have a blockage towards the rads.
ok DP, before I start, what do you mean by taking temperature of cold and hot water?
Do you mean take the temp of the red and pink pipes before the boiler starts up then after the hot water kicks in?
Want to get this right first time.
Do you mean take the temp of the red and pink pipes before the boiler starts up then after the hot water kicks in?
Want to get this right first time.
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DP, you have misread my findings.
Boiler fired first time for 16 mins. After 16 mins the return was 40.5. Think you were possibly reading the return reading after 7 mins running?
I measured the return temperature improving over the initial 16 mins firing to prove an increase in the return temp.
Does this make sense?
Boiler fired first time for 16 mins. After 16 mins the return was 40.5. Think you were possibly reading the return reading after 7 mins running?
I measured the return temperature improving over the initial 16 mins firing to prove an increase in the return temp.
Does this make sense?
SOrry fluff about the 130 vs 133, I thought the RED might help
YOu gotta understand how this boiler thing works. Is that 133 pipe getting hot from the return pipe coming up from below the boiler, or from the DHW/plate/blue heat exchanger?
If cooler than the return pipe it's not a problem. If it's hotter, it is.
Eventually the whole of the blue HE will get hot IF the diverter is letting water through when it shouldn't.
SO if I was standing at the boiler I'd feel around as the CH comes on and see how long it takes things tro get hot, and in what order.
You can easily cool the blue HE down - turn the boiler OFF and run the hot tap.
This should show it. Red is Hot, pinky purple is warm, light blue is cold.
In the Hot Water mode, the tap water goes from light blue to dark blue.
Note the movement of the yellow thing in the DV. If it doesn't quite make it to CH mode, you get the situation I drew before
YOu gotta understand how this boiler thing works. Is that 133 pipe getting hot from the return pipe coming up from below the boiler, or from the DHW/plate/blue heat exchanger?
If cooler than the return pipe it's not a problem. If it's hotter, it is.
Eventually the whole of the blue HE will get hot IF the diverter is letting water through when it shouldn't.
SO if I was standing at the boiler I'd feel around as the CH comes on and see how long it takes things tro get hot, and in what order.
You can easily cool the blue HE down - turn the boiler OFF and run the hot tap.
This should show it. Red is Hot, pinky purple is warm, light blue is cold.
In the Hot Water mode, the tap water goes from light blue to dark blue.
Note the movement of the yellow thing in the DV. If it doesn't quite make it to CH mode, you get the situation I drew before
Chris, will try to comprehend your post in a minute.
DP - ran the bath tap full. The red pipe heated to 65.9 and the pink pipe heated to 49.7. This is with the DHW stat at no.7 on the boiler as well.
Don't have a probe for checking water temperature, only have a surface probe. However, hot water is so hot that you would not be able to sit in it. Had to add alot of cold water for my daughter a couple of mins ago.
hope this helps
DP - ran the bath tap full. The red pipe heated to 65.9 and the pink pipe heated to 49.7. This is with the DHW stat at no.7 on the boiler as well.
Don't have a probe for checking water temperature, only have a surface probe. However, hot water is so hot that you would not be able to sit in it. Had to add alot of cold water for my daughter a couple of mins ago.
hope this helps
Right ChrisR, think I understand how the heating up works.
Left picture is the CH, hot water comes from heat exchanger, down the red pipe, diverter valve should send all the water down the CH flow pipe.
Right picture is the DHW, hot water comes down the red pipe, diverter valve switches to the other exchanger, hot water comes out secondary heat exchanger and down the DHW pipe plus some warm water will come back up to the primary heat exchanger via the pump.
HAve I got that bit right. ALso, from my photo earlier on, is the heat exchanger that you can see for the DHW with the primary heat exchanger being up above the gas burner? If it is the DHW exchanger, I better clarify that this was the exchanger that I took the surface temperature off of earlier today. about 42 degs.
Therefore in CH mode, i should only have the red flow pipe getting really hot and the return pipe getting slightly hot. should pipe 133 get warm, it was the same temp as the CH return pipe earlier on in CH mode.
If the heat exchanger that I can see is for the DHW, why is pipe 133 getting warm when the CH is on?
You asked me to check the temp on the 133 pipe. Is this the pipe which returns the warm water in DHW mode through the pump back to the primary heat exchanger?
Chris R, re-reading your earlier post, my boss's first thought was the temperature sensor but the alpha agent ruled this out, but with no theory. He just said that the boiler was reaching temperature properly and was cutting out because there was a blockage.
Left picture is the CH, hot water comes from heat exchanger, down the red pipe, diverter valve should send all the water down the CH flow pipe.
Right picture is the DHW, hot water comes down the red pipe, diverter valve switches to the other exchanger, hot water comes out secondary heat exchanger and down the DHW pipe plus some warm water will come back up to the primary heat exchanger via the pump.
HAve I got that bit right. ALso, from my photo earlier on, is the heat exchanger that you can see for the DHW with the primary heat exchanger being up above the gas burner? If it is the DHW exchanger, I better clarify that this was the exchanger that I took the surface temperature off of earlier today. about 42 degs.
Therefore in CH mode, i should only have the red flow pipe getting really hot and the return pipe getting slightly hot. should pipe 133 get warm, it was the same temp as the CH return pipe earlier on in CH mode.
If the heat exchanger that I can see is for the DHW, why is pipe 133 getting warm when the CH is on?
You asked me to check the temp on the 133 pipe. Is this the pipe which returns the warm water in DHW mode through the pump back to the primary heat exchanger?
Chris R, re-reading your earlier post, my boss's first thought was the temperature sensor but the alpha agent ruled this out, but with no theory. He just said that the boiler was reaching temperature properly and was cutting out because there was a blockage.
Anybody
Should I phone Homeserve and tell them that I do not want them to look at the diverter valve?
I am scared that I may get billed for wasting their time if this is not broken. I thought opening the tap proved something but possibly not if the valve isn't passing.
Biggest problem will be if the engineer says that it is a blockage again and I need to powerflush - homeserve may charge me this time.
thanks
fluff
Should I phone Homeserve and tell them that I do not want them to look at the diverter valve?
I am scared that I may get billed for wasting their time if this is not broken. I thought opening the tap proved something but possibly not if the valve isn't passing.
Biggest problem will be if the engineer says that it is a blockage again and I need to powerflush - homeserve may charge me this time.
thanks
fluff
HW readings indicate boiler function correctly. At 7 flow is indicating 66. At full, it will most likely go to 70/75.
If you take the temperature off the cold pipe and then the hot pipe with bath tap running full tilt, expect the difference to be 35 degrees if all is set correctly.
Hold off the homeserve for a moment. We appear to be going someplace.
You CH readings indicate blockage, but that will be confirmed once you have had a chance to read off hot and cold pipe temperatures and measured the flow at the hot tap for 15 seconds.
If you take the temperature off the cold pipe and then the hot pipe with bath tap running full tilt, expect the difference to be 35 degrees if all is set correctly.
Hold off the homeserve for a moment. We appear to be going someplace.
You CH readings indicate blockage, but that will be confirmed once you have had a chance to read off hot and cold pipe temperatures and measured the flow at the hot tap for 15 seconds.
Yes Fluff you're getting it!
pipe 133 is here:
You'll appreciate that it should only get hot for tap water. The lower end of it (where the drain cock is) would get warm from conduction from the CH return pipe, but only a bit. As I said, diagnosis rests on which gets hotter first, the CH return pipe or pipe 133.
If the apple core yellow bit iisn't sealing, that would make 133 eventually get up to nearly as hot as the CH flow pipe, because both sides of the tap water heat exchanger would just get hot - there's nothing to cool it.
It sounds like that isn't happening, IF 133 only gets to 40 something after the flow pipe has been at 70 for a few minutes.
I retract concerns about the sensor, for now.
WHere are you, Fluff - one of us might be just round the block! I think it might be quicker...
pipe 133 is here:
You'll appreciate that it should only get hot for tap water. The lower end of it (where the drain cock is) would get warm from conduction from the CH return pipe, but only a bit. As I said, diagnosis rests on which gets hotter first, the CH return pipe or pipe 133.
If the apple core yellow bit iisn't sealing, that would make 133 eventually get up to nearly as hot as the CH flow pipe, because both sides of the tap water heat exchanger would just get hot - there's nothing to cool it.
It sounds like that isn't happening, IF 133 only gets to 40 something after the flow pipe has been at 70 for a few minutes.
I retract concerns about the sensor, for now.
WHere are you, Fluff - one of us might be just round the block! I think it might be quicker...
SOmething else...
Watch the gas meter when you put the CH on. Time it to determine the "gas rate". See FAQs on how.
WHen its on for the first 15 minuites or whatever, it should go from high rate to much lower (modulation).
Not quite sure how this boiler behaves timewise but it might start at 24kW and go down to its low end quite quickly - 9kW or whatever it was,
Watch the gas meter when you put the CH on. Time it to determine the "gas rate". See FAQs on how.
WHen its on for the first 15 minuites or whatever, it should go from high rate to much lower (modulation).
Not quite sure how this boiler behaves timewise but it might start at 24kW and go down to its low end quite quickly - 9kW or whatever it was,
This must be the longest running cold spot on a radiator topic in the world. We have gone from an undersized 8mm pipe supplying a 600 x 1600K2 to the boiler being at fault probably because the system has been "balanced" to strangulation.
Without reading through all this bumpf again if you have still got all your radiators "balanced" which i think was done around April?? then unbalance them and give the water a chance to get through the pipes.
Minibore systems require very little balancing
Without reading through all this bumpf again if you have still got all your radiators "balanced" which i think was done around April?? then unbalance them and give the water a chance to get through the pipes.
Minibore systems require very little balancing
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