water pump not running on

[capt.dunc]

hi, hope i've put this in the right place, i've got a problem with my cental heating pump not running properly. it's a grundfos ups2 in a closed loop with a gas boiler.

it kicks in for about a second, before stopping, and then kicking in again about 2 seconds later, for a second, etc etc. got power and impeller's turning free for that brief moment but it's not pulling enough hot water from the boiler which is causing overheating and kettling.

no air locks and i've drained the system about 5 times to clear muck, water pale yellow at the moment. boiler and stats and gas all fine, pump about 40 days old, it'd jambed with a stone which i've cleared (no idea how that got into the closed loop, could of been there 30 years), the pump ran again after the jam and started to heat the top of all rads in the system for about 20mins before stopping again.

any advice?

tomorrow i'm going to look at the electric points in the pump in case there's anything obviously wrong but the lights are on and it does fire to start turning.

 

[Dotty]

What setting is it on?

 

[capt.dunc]

1,2 or 3 makes no difference

 

[AWheating]

Sounds like you have knackad it. The pump valves are open/ not blocked?

 

[capt.dunc]

just fitted new pump valves yesterday, the old ones were leaking a little and i was wondering if they were letting air in

 

[capt.dunc]

changed both valves yesterday, had them open and there's flow into the pump and from the exit line. checked in the pump, no sign of electrical damage or faulty wiring. looks like i'm going to have to buy a second pump in as many months

 

[LPC]

The pump will have a warranty on it. Take it back.

How did your system get a stone in it??

 

[capt.dunc]

already ordered new pump, the landlord will be picking up the bill in the long run anyway, wasn't sure if it'd covered since the pump shouldn't have to deal with such abuse in use.

there's 3 ways the stone could of got in,

1 the engineer picked up a stone and put it in the pipe work, there's no way to fall in.
2 the water mains has brought it in
3 it's been lying in the pipes for more than 20 years since the pipes were laid along under the floor, and the recent work has moved it along and it's been sucked up by the new pump.

i'm going for number 3.

it'll be the end of next week before the new pump gets here, i'll report back to let you all know if it does the job

 

[capt.dunc]

new pump fitted and running smooth.

 

[capt.dunc]

new pump worked for one week, and heating and hot water all ran great, had cleaner through the system in that time. then pop, pump's stopped and back to square one, what could be causing pump after pump to fail?

 

[PhoenixServices]

I would say something electrical, might pay to get a sparky in to fault find.

 

[rpm]

Do these have capacitors?