Grundfos UPS 15-50 130 Pump

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Hi all,

I have a Grundfos pump which seems to be struggling to start on its own. Yesterday I noticed the house wasn’t heating up very quickly and as I had the same issue about a year ago, went straight to the pump. I opened the valve and the spinner wasn’t spinning. Whilst calling for heat, I used my screwdriver to turn the spinner either way and it still didn’t start spinning. After some time I realised I needed to push the spinner into the pump for it to start catching to then start spinning?! Eventually after a few attempts, it maintained spinning and seemed to be operating (at least to some degree). This morning after the heating was off overnight, the same issue has happened. Do I need a new pump or is there a part I can replace to save cost? Thanks in advance. Chris
 
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Update, I’ve just had to kick start it again and the heating hasn’t been off!
 

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1. The start capacitors are replaceable. They are about 7 or 8 microfarads, but MUST be mains AC rated. Not electrolytics.
2. However, it sounds a more mechanical fault if you have to push on the spindle to get it to start. I'd replace the whole pump.
 
...... and maybe get the system cleaned. That may be more obvious when you have removed the old pump and can inspect the volute. THese circulators use the system water for lubrication and cooling and any crud can jam the rotor in the stator.
 
The system was flushed and cleaned about 2 year’s ago. All rads are new as renovated the house. Which replacement am I getting where I can swap myself please? I’m in a 5 bed house. Thanks, Chris
 
1. I'd suggest a Grundfos UPS3 15-50/65.
2. You will need to:
2a. Turn off the boiler and make sure there is no power to the pump. If necessary, turn off the main switch in the consumer unit.
2b. Make a not of which direct the pump is pumping by checking the arrow moulded onto the main body of the pump.
2c. Shut the valves either side of the pump. These may be gate valves with a squared spindle for a spanner, or 1/4 turn valves with a screwdriver slot. There are a few other possibilities, but the principle remains the same. Note that these valve, particularly the 1/4 turn ones, are not very reliable and may leak. Gate valves can be very stiff, and can jam open or shut. If you end up having to replace the valves, it is drain down time and you might need a professional.
2d. Undo the nuts securing the valves to the pump. These can be very stiff, and need a good deal of force to shift. You need to try and hold the body of the pump to stop it rotating around the connection axis. Help from someone else to stop the valves turning on the connection is useful.
2e. Remove the old pump, and remove and discard the old (usually black rubber) sealing washers.
2f. Before fitting the new pump, make sure it is going to be pumping in the same direction as the old, and that, when fitted, the electrical "box" will be at the top and not susceptible to water ingress. The pump should also be vertical or horizontal about its spindle when fitted, the instructions with the pump tell you what to do.
2g. Fit the new pump. Make sure the new sealing washers are used, and are properly in place. The nuts on the valves can come off, which is a nuisance, but they have a groove in their flanges in one place, and can be put back on again. If you can, put some silicone grease around the threads on the pump body before doing up the nuts. It will make the next replacement easier!. The nuts should be done up firm hand tight, then another 1/4 to 1/2 turn with a spanner. There is no need to overtighten, it does no good an can damage the seals. If it weeps when re-connected, nip them up a little more.
2h. The new pump will come with a special plug. From memory, this is pre-wired, which means you will have to connect the other end into the wiring centre. Earlier versions had screw down terminals in the pump, so you could use the old wires and not disturb the wiring centre.
2i. Open the pump valves, check for leaks, and the job is done.
Points to note:
a. The valve nuts on the pump end of the valves are big. You will need a very big spanner (e.g. Screwfix 37949) or some very big grips.
b. It's important not to let the valves turn on the pipes, it can cause the connections to weep.
 
Hi all so an update. New pump has arrived, gone to switch valves off and at least one of them isn’t holding which means a system drain. I’m thinking it may be an idea to replace the valves at the same time as the system drain? If so can anyone recommend suitable valves I need please? Current ones say 28mm on them.
Cheers, Chris
 

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1. When you say one of the valves isn't holding, what do you mean?
2. The valves are on vertical pipes. These are usually the least troublesome, as the muck which can cause them to let by is usually washed through. Try slackening the gland nut (the smaller brass nut nearest the handle end of the spindle) a turn, then opening and closing the valve a few times. Might seal better.
3. If its only letting a small amount of water through, you could consider just letting it run and catching the water in buckets / old towels etc. provided you are quick with the pump change.
4. Or consider freezing the offending pipe.
5. If the pipe outside diameters are 28 mm then you need 28 mm valves. Screwfix 1743V would do, but if you can find them Pegler valves are probably better quality. Whatever you do, don't get the valves with 1/4 turn screwdriver slots.
 

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