Help - no water getting to water pump??

[djw76]

hi

a noticed a small leak on nut above water pump the other day so tried fixing it but since then i've having major problems.

was getting loud banging from boiler and it was locking out.

pump was running but getting hot.

2 pipes leading up from boiler were getting hot but none of this was getting to any pipes above in airing cupboard.

you can feel water moving in the pipes above and below pump.

i decided to take the head of the water pump to check that and discovered no water (either side) is coming out of the gate valves even open?! so obviously the pump was running dry and getting hot.

surely both gate valves should release water when open?!

could an airlock cause this or are gate valves not opening??

thanks

 

[Agile]

How do you "feel" water ? When there is none?

Have you read the FAQ on this site about your header tank?

Tony

 

[djw76]

what i mean is if i grip the pipe above or below pump i can feel a slight vibrating as if water is circulating through pipes. however it seems to not be getting through the gate valves into the pump?

i haven't read that, but checked my header tank and it's got water in.

 

[oilboffin]

Could be the feed pipe from the tank is blocked

 

[djw76]

i've lost not much more than a trickle from the system so would that be enough to trigger the refilling from the header tank? i bled upstairs radiators and was getting water out immediately from them so does that mean the system is sufficiently full?

 

[JohnD]

what i mean is if i grip the pipe above or below pump i can feel a slight vibrating as if water is circulating through pipes.

It might be the vibration of the motor spinning in its dry bearings, and grinding them. Without water it will wear out and jam quite quickly.

 

[djw76]

i think you could be right there. i think after repeated tries and therefore overheating it has now jammed. however i've taken it apart and it will turn but not freely. will the power of the motor still be able to turn it or new pump time?

 

[just pumps]

With the pump out check the valves are letting pass before fitting the new pump or you will be buying 2 new pumps.

 

[just pumps]

Pump shaft should rotate freely when not under load. sounds like new pump time.

 

[Agile]

Sometimes when in water the water lubricates them and they turn easier.

But your underlying problem seems no water in the system.

Tony

 

[djw76]

Sometimes when in water the water lubricates them and they turn easier.

But your underlying problem seems no water in the system.

Tony

might not be time to throw it just yet then.

need to sort these valves first and get water flowing through it!

 

[Agile]

I don't think there is any water on the other side of the valves!

As suggested, loosen one of the valve nuts a couple of turns and see if water dribbles out.

I expect not so you could then take the valve right off.

Tony

 

[djw76]

well i didn't expect that.....

after draining (drip by drip) all morning the pipework from header tank to pump valve, and removing said valve it is operating okay?!?

don't get it, it definitely wasn't opening in situ as water was otherside of the valve!

is it possible for them to fail to open but not actually be broken??

 

[just pumps]

Only if the wheel is rotating but not operating the shaft.

 

[Agile]

I think your blockage only allows a drip by drip feed of water!

Tony