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Discuss New Grundfos UPS3 15-50/65 130 Circulator pump fitted no heating and hot water - FD Fault code in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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I have a 5 year old Ideal Logic 15 boiler that has been working alongside an old Grundfos pump possibly about 10years old. The boiler was recently (about 3 weeks ago) repaired and services by an Ideal technician.

I had a plumber yesterday from Local Heros who came to fit a new Grundfos UPS3 pump as the one that was there showed signs of being on its way out. The plumber could not get the central heating or hot water back up and the boiler was no longer igniting. The plumber said that it will no longer work as the system is dirty and may have clogged even though the boiler was previously working with the old pump.

After the plumber had left, I went on a mission to try and get the system back up by performing the following.
  • Bled all the radiators
  • Removed any air from the system using the release valve (not sure of the correct term) between the pump and the emersion heater
  • Powered down the boiler for about 10 mins and switched it back on.
The boiler ignitor fired up, the radiators warmed up and we had hot water. The heating was on for about 3 hours before switching it off last night. The next morning everything was working accordingly for about 2 hours until the heating was turned off. From that point the boiler was now showing an FD error (meaning a circulation problem from what I have gathered).

My questions are:
  • Would the boiler have worked if the pump was fitted in the wrong direction?
  • What could be possibly going wrong? Could it be a dodgy pump that I bought? If it is a dodgy pump, is there any way of checking to make sure that it is working. I have looked at the pump manual and there are no errors shown on the pump indicating that it is working.
  • If the system is clogged up, how has it been working with the old pump and not with the new one.
Any advice on how I can resolve this issue would be greatly appreciated. I am concerned that I may keep paying for work without anything being resolved. Many thanks.
 
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Is your system sealed with a expansion vessel or is there a small tank in the attic adjacent to the much larger cold water storage tank?.

If a sealed system what is the pressure gauge on the boiler showing?

Was the system drained down to install the new pump?.

Its possible that it was installed wrong way round (unlkely) can you see where its installed, if on the flow from the boiler then the arrow on the pump body should be pointing away from the boiler, if installed on the return should be pumping into the boiler.
If installed in the hot press adjacent to the HW cylinder, pump arrow should be pointing towards the cylinder. (post photo if possible)

Pump could be faulty, again unlikely.

Can you see from the pictogram below what setting the pump is presently on, or post a photo while running. the yellow LED(s) may show up as solid or flashing depending on the selected mode.


1634099860141.png
 
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Messages
4
Is your system sealed with a expansion vessel or is there a small tank in the attic adjacent to the much larger cold water storage tank?.

If a sealed system what is the pressure gauge on the boiler showing?

Was the system drained down to install the new pump?.

Its possible that it was installed wrong way round (unlkely) can you see where its installed, if on the flow from the boiler then the arrow on the pump body should be pointing away from the boiler, if installed on the return should be pumping into the boiler.
If installed in the hot press adjacent to the HW cylinder, pump arrow should be pointing towards the cylinder. (post photo if possible)

Pump could be faulty, again unlikely.

Can you see from the pictogram below what setting the pump is presently on, or post a photo while running. the yellow LED(s) may show up as solid or flashing depending on the selected mode.


View attachment 64551
Thank you for response John. I have just checked the attic and can confirm that there is a small tank adjacent to the cold water storage. I’m not sure if it is possible to send a photo as I am a newbie to this forum.

The system was not drained as part of fitting the pump. It was more of a straight swap and everything was fired up. The arrow is pointing towards the direction of the emersion heater.

Looking at the pictogram, I can confirm that the pump is set to ‘III Constant Curve III’ showing 1 solid Green light and 2 solid Orange lights as shown on the left hand side of the pictogram.

Would the CH and HW have briefly worked if the pump was incorrectly fitted?
 

ShaunCorbs

Staff member
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Plumber
Gas Engineer
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Shut all but one rad closet to the pump and let it run and keep bleeding the air vent if there’s air coming out
 
Messages
1,934
Thank you for response John. I have just checked the attic and can confirm that there is a small tank adjacent to the cold water storage. I’m not sure if it is possible to send a photo as I am a newbie to this forum.

The system was not drained as part of fitting the pump. It was more of a straight swap and everything was fired up. The arrow is pointing towards the direction of the emersion heater.

Looking at the pictogram, I can confirm that the pump is set to ‘III Constant Curve III’ showing 1 solid Green light and 2 solid Orange lights as shown on the left hand side of the pictogram.

Would the CH and HW have briefly worked if the pump was incorrectly fitted?
NO, they wouldn'nt and you have confirmed that it is installed correctly.
What I suspect that may be the problem especially with the open vented system is that with the new pump which is a very powerful pump especially at top speed setting 3 at 6M is that it may be pumping over into that small header tank and/or pulling air into the system.
I would suggest go to to the attic and watch the vent (where it bends over the tank), get someone to start and after a few minutes stop the pump and see if any water spurts out that vent, if so, that is your problem, if you don't see anything hold a "glass" of water with the vent immersed in it (with pump ru nning) and see if it pulls any water from the glass.
That 6M setting is ridiculously high in any case so after your observations above set it to CP1 (3M) and if still problems in the attic, set it to PP2 which is around 2.3M with all systems running.......and keep venting.
I have said it before but you could fill a small book with problems with open vented systems on the apparently simple change out of circulating pumps because people don't look at the old pump settings and match the new pump setting to them.
 
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