I go to lots of sludged up systems which were correctly installed but the tenants just leave the filling valve letting by and thus resulting in a totally sludged up system. A few owners do that as well.
Tony
Potterton Kingfisher MF - problem
- Thread starter TWJ
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I go to lots of sludged up systems which were correctly installed but the tenants just leave the filling valve letting by and thus resulting in a totally sludged up system. A few owners do that as well.
Tony
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could you explain to me what the "electrical module" is on the pump ?
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Tony: "I go to lots of sludged up systems which were correctly installed but the tenants just leave the filling valve letting by and thus resulting in a totally sludged up system. A few owners do that as well."
GK: Probably me! What do you mean?
spacethegas: "could you explain to me what the "electrical module" is on the pump ?"
GK: The main pump body is cylindrical. Fixed to the side of this there is a square-shaped holder containing a small circuit board. The outer face of this holder is a plastic cover on which is mounted the selector switch for changing the pump speed. This is what I mean by the "electical module". When these pumps fail it is nearly always because the electrics burned out. You can't buy the modules separately AFAIK, but what you can do is buy an identical pump and swap the circuit board out of it into the old pump while still in situ. This saves you draining the system to remove the old pump and then installing the new pump with new joints etc. You can still swap the new pump in later on if the old one wears out mechanically.
GK: Probably me! What do you mean?
spacethegas: "could you explain to me what the "electrical module" is on the pump ?"
GK: The main pump body is cylindrical. Fixed to the side of this there is a square-shaped holder containing a small circuit board. The outer face of this holder is a plastic cover on which is mounted the selector switch for changing the pump speed. This is what I mean by the "electical module". When these pumps fail it is nearly always because the electrics burned out. You can't buy the modules separately AFAIK, but what you can do is buy an identical pump and swap the circuit board out of it into the old pump while still in situ. This saves you draining the system to remove the old pump and then installing the new pump with new joints etc. You can still swap the new pump in later on if the old one wears out mechanically.
far easier to change the pump head & then you can inspect the impeller assembly as it may well give you a clue as to the condition of the circulating system water & hence why the pump went bang.
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[spacethegas]far easier to change the pump head & then you can inspect the impeller assembly as it may well give you a clue as to the condition of the circulating system water & hence why the pump went bang.[]
GK: You're probably right. I just tried an experiment. With the HW in the tank up to the setpoint of 60degc, I turned it up further to call for heat. The boiler came on but within a couple of minutes it shut down completely with the red overheating light on. Presumably that means the boiler can't deal with heating water that is already at 60degC, because the water flow through the heat exchanger isn't fast enough to stop overheating.
I'll replace the pump and see what happens.
GK: You're probably right. I just tried an experiment. With the HW in the tank up to the setpoint of 60degc, I turned it up further to call for heat. The boiler came on but within a couple of minutes it shut down completely with the red overheating light on. Presumably that means the boiler can't deal with heating water that is already at 60degC, because the water flow through the heat exchanger isn't fast enough to stop overheating.
I'll replace the pump and see what happens.
GFK I think you are missing the action!
The cylinder temperature is one value and the boiler temperature is another.
Its the boiler overheating because the pump is not working properly OR the system is sludged.
Tony
The cylinder temperature is one value and the boiler temperature is another.
Its the boiler overheating because the pump is not working properly OR the system is sludged.
Tony
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TONY: I think you are missing the action! The cylinder temperature is one value and the boiler temperature is another.
GK: I know. But the boiler is being fed with water from the HW tank heat exchanger, so if that water is already very hot it might tend to make the boiler overheat when the boiler starts to heat it even hotter. That's what I thought anyway.
TONY: Its the boiler overheating because the pump is not working properly OR the system is sludged.
GK: Yes, but the boiler doesn't always overheat. Just sometimes.
By the way, what was it you meant earlier on when you said "... the tenants just leave the filling valve letting by and thus resulting in a totally sludged up system. " What are they doing wrong and what makes the sludge?
GK: I know. But the boiler is being fed with water from the HW tank heat exchanger, so if that water is already very hot it might tend to make the boiler overheat when the boiler starts to heat it even hotter. That's what I thought anyway.
TONY: Its the boiler overheating because the pump is not working properly OR the system is sludged.
GK: Yes, but the boiler doesn't always overheat. Just sometimes.
By the way, what was it you meant earlier on when you said "... the tenants just leave the filling valve letting by and thus resulting in a totally sludged up system. " What are they doing wrong and what makes the sludge?
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Also Tony, on another interesting thread where the owner's problem was a bit like mine (//www.diynot.com/forums/viewtopic.php?t=116921) you said:
"The temperature sensor on the front of the boiler must be packed with thermal transfer paste and few people do that when removing or replacing them. It can cause them to overheat!"
By this do you mean that if there is not enough paste then the boiler is apt to overheat? Or that too much paste makes it overheat? I've had the sensor out for testing and there is some paste on it but not all that much.
"The temperature sensor on the front of the boiler must be packed with thermal transfer paste and few people do that when removing or replacing them. It can cause them to overheat!"
By this do you mean that if there is not enough paste then the boiler is apt to overheat? Or that too much paste makes it overheat? I've had the sensor out for testing and there is some paste on it but not all that much.
A filling loop left open brings new oxygen into thre system which rusts the inside of the rads and forms mobile sludge which blocks everything.
One of my ex-trainees had an overheating KF but said everything else was fine.
I told him he needed to pack the sensor with heat transfer paste. He would not believe me at first!
..........until he tried it and found it worked!
If the flow and return to the cylinder are both hot then either the flow rate is too high or the heating coil is not transfering the heat as a result of scaling etc. There should be about 11°C differential with a standard boiler.
Tony
One of my ex-trainees had an overheating KF but said everything else was fine.
I told him he needed to pack the sensor with heat transfer paste. He would not believe me at first!
..........until he tried it and found it worked!
If the flow and return to the cylinder are both hot then either the flow rate is too high or the heating coil is not transfering the heat as a result of scaling etc. There should be about 11°C differential with a standard boiler.
Tony
Tony maybe I should have added the quallifier provided the system hasn't been abused!
Regarding leaving filling valve open does in a way seem strange. The water has to go somewhere, that somewhere is normally the pressure release valve and would result in a fair amount of water discharge.
As I said strange; but then according to the saying 'there's none stranger than folk'.
Tenants are not concerned about overflows.
Even many semi owners dont bother about loft tanks overflowing until the neighbour complains.
Same with upstairs flat owners, they wait until downstairs flat complains.
I went to one recently which had been discharging about 5 li/min for many weeks. The landlady ended up with a bill of about £225 for a replacement main heat exchanger and compliant filling loop.
Tony
Even many semi owners dont bother about loft tanks overflowing until the neighbour complains.
Same with upstairs flat owners, they wait until downstairs flat complains.
I went to one recently which had been discharging about 5 li/min for many weeks. The landlady ended up with a bill of about £225 for a replacement main heat exchanger and compliant filling loop.
Tony
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Just to round this off - I finally got around to fixing it, and not before time, because the thing was cluck-clucking all day long like an old hen and I thought it was going to pack up. I orderd a main PCB from one of the online catalogues - gasbits.com - and fitted it myself. Now works like a charm. Cost £100.
I still intend to replace the circulator - it's a little under-specced for my boiler - but that can wait until the weather's warmed up a bit.
I still intend to replace the circulator - it's a little under-specced for my boiler - but that can wait until the weather's warmed up a bit.
My boiler has just made heavy clanking sound so switched off, anay ideas on the problem please ?
Dead pump.
This thread is a little old though don't you think?
Start a new thread with some information specific to you.
This thread is a little old though don't you think?
Start a new thread with some information specific to you.
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