New Grundfos slow to start after 2 weeks, replacement did the same...
- Thread starter Thandar
- Start date
- Status
Sponsored Links
Sponsored Links
- Joined
- 22 Jan 2007
- Messages
- 8,368
- Reaction score
- 4,216
- Country
What make and model of boiler have you got btw?
And get that 4trade $hite flushed fully out the system. Its not the worst offender for pump failure x800 is, but I've had a recent spate of pump faults on relativley new boiler installs and they all had the one thing in common 4trade cleanser and it clearly wasnt flushed out fully.
Flushing is not a matter of opening the drain valve and letting the F+E tank run through the system for a bit. the water needs Isolating to the tank, open drain, open any zonevalves and radiator thermostats, then open all radiator bleed points to let air into the rads to let the water drain out till the system is essentially empty, then refill, vent, circulate and keep venting till heat is at all rads again, then drain again, can take half a dozen times to get the system water clear of cleanser.
The next time it drains, once you open the bleed points on the rads to get them draining, fill an empty coke/juice bottle with whats draining out, if there is a green/brown/orange/black colour to it, then the cleanser is still far too concentraded in the system.
And get that 4trade $hite flushed fully out the system. Its not the worst offender for pump failure x800 is, but I've had a recent spate of pump faults on relativley new boiler installs and they all had the one thing in common 4trade cleanser and it clearly wasnt flushed out fully.
Flushing is not a matter of opening the drain valve and letting the F+E tank run through the system for a bit. the water needs Isolating to the tank, open drain, open any zonevalves and radiator thermostats, then open all radiator bleed points to let air into the rads to let the water drain out till the system is essentially empty, then refill, vent, circulate and keep venting till heat is at all rads again, then drain again, can take half a dozen times to get the system water clear of cleanser.
The next time it drains, once you open the bleed points on the rads to get them draining, fill an empty coke/juice bottle with whats draining out, if there is a green/brown/orange/black colour to it, then the cleanser is still far too concentraded in the system.
It's difficult to see in the pics, but what, exactly, is preventing the pump being installed with the shaft horizontal?
If it's the control box on the side, the head can be removed and rotated 90 degrees clockwise so the control is on the top.
If it's the control box on the side, the head can be removed and rotated 90 degrees clockwise so the control is on the top.
I'm not sure why they tilted it, I had a brainwave this morning and moved it by using the nuts on the isolators and moving the whole thing, there was nothing stopping it being horizontal, I'm not sure they weren't trying for vertical...
So now it's horizontal, however it's still the same, not starting correctly, so that doesn't appear to be it
Here is a pic with Homer to show orientation
So now it's horizontal, however it's still the same, not starting correctly, so that doesn't appear to be it
Here is a pic with Homer to show orientation
I do hope they were not trying to do that! It would kill the pump very quickly as the top bearing would not get any lubrication.
[Your last post]
Where did you measure the voltage - was it at the other end of the white wire? If so, does this connect to a junction box or the boiler?
Which boiler do you have (make and exact model)?
I really wonder why people use cheap chemicals when the Sentinel and Fernox are the industry standards.
There is clearly something not right. Now the pump is at the right angle that should have eliminated it from the list. I would have estimated the previous angle as almost 45 degrees above the horizontal.
But have you measured 240 v at the same time as when it fails to start?
Which operating setting is it on and have you tried changing that?
Tony
There is clearly something not right. Now the pump is at the right angle that should have eliminated it from the list. I would have estimated the previous angle as almost 45 degrees above the horizontal.
But have you measured 240 v at the same time as when it fails to start?
Which operating setting is it on and have you tried changing that?
Tony
I'm now thinking a dodgy pump housing might be the issue, I've worked out a way to close the isolator valves so I'll try getting inside to have a look....
I measured the voltage at the box the wire goes to, it's a cheap connector block and the inputs appear to be from the boiler and the orange wire from the three-way valve, and it was measured at over 240V when it tries to start, rock solid, no dip.
It was on 3 and I've dropped it to 2 with no difference, I would say it's now sticking after a shorter and shorter period, also tapping the right spot on the back of the pump seems to get it to go straight away
I measured the voltage at the box the wire goes to, it's a cheap connector block and the inputs appear to be from the boiler and the orange wire from the three-way valve, and it was measured at over 240V when it tries to start, rock solid, no dip.
It was on 3 and I've dropped it to 2 with no difference, I would say it's now sticking after a shorter and shorter period, also tapping the right spot on the back of the pump seems to get it to go straight away
Update, I decided to clean out the tank in the attic so held the ballcock and bailed the water into a bucket.
Only is was more mud than water, I was actually worried about it cloging the drains so I wouldn't think it's good for the heating pipes....
However it's made no difference.
Als I've decidided tapping the pump does nothing, now think it's the warming effect, or the water current from the kettling
Only is was more mud than water, I was actually worried about it cloging the drains so I wouldn't think it's good for the heating pipes....
However it's made no difference.
Als I've decidided tapping the pump does nothing, now think it's the warming effect, or the water current from the kettling
The wire to the boiler is an output, it's what makes the boiler run. There should also be a wire from the HW cylinder thermostat.
Inputs: HW thermostat and valve orange
Outputs: Pump and boiler
There may be 240V in the junction box, but is there 240V at the pump (dodgy cable etc). This Grundfos Video shows you how to get to the connections at the pump end.
Is it an old pump (Selectric) which has just had the head replaced by a UPS2?
If the tank was that bad, the whole system is probably full of muck and needs flushing through.
Drain down (open any motorized valves)
Refill and drain until the water coming out is reasonably clear.
Refill adding Sentinel x400 cleaner during the fill via the F&E tank.
Run the boiler for two weeks.
Drain and refill until water runs reasonably clear
Refill adding Sentinel X100 inhibitor and X200 if you have very hard water.
OK, been testing the pump and I'm now fairly sure where the fault lies...
Took off the big screw in the center and put my finger on the main shaft inside, and switched the system on, the pump is trying to start, every 3 seconds or so it fires and does half a revolution, there appears to be no drag on the pump, it turns freely.
Electrical motor work by one winding supplying enough EMF to move the rotor onto the next winding, if the next one is dead then it has to jump as far as the next one after that, once it's going it's fast enough to not be an issue.
Could be a burnt out winding, however if the pump stops on the dead winding then it should get stuck not not move at all, which is not happening.
The other possibility is that the starter has an issue, it looks like most work on a starting capacator but not sure if that's how these work, I can't get the electrical cover off without taking the pump head off as it's too tight against the isolator valve..
And the greatest mystery is how it can happen to 2 pumps, each after 2 weeks each, and how whatever issue it is doesn't stop it working completely
Took off the big screw in the center and put my finger on the main shaft inside, and switched the system on, the pump is trying to start, every 3 seconds or so it fires and does half a revolution, there appears to be no drag on the pump, it turns freely.
Electrical motor work by one winding supplying enough EMF to move the rotor onto the next winding, if the next one is dead then it has to jump as far as the next one after that, once it's going it's fast enough to not be an issue.
Could be a burnt out winding, however if the pump stops on the dead winding then it should get stuck not not move at all, which is not happening.
The other possibility is that the starter has an issue, it looks like most work on a starting capacator but not sure if that's how these work, I can't get the electrical cover off without taking the pump head off as it's too tight against the isolator valve..
And the greatest mystery is how it can happen to 2 pumps, each after 2 weeks each, and how whatever issue it is doesn't stop it working completely
You can rotate the pump valve on its own.
But we still don't know where the pump is supplied from.
It has to be directly from the boiler pump output terminals so that it can provide pump over run.
The boiler also must have a permanent live and a switched live going back to the orange wire!
Tony
But we still don't know where the pump is supplied from.
It has to be directly from the boiler pump output terminals so that it can provide pump over run.
The boiler also must have a permanent live and a switched live going back to the orange wire!
Tony
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
- Status
Sponsored Links
