Shower pump problems (Grundfos Niagara)

D

DannyBoy

Registered User
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Hi folks,

Dunno if you've come across anything like this, but any help would be appreciated.

We just had a pump installed to supply the two bathrooms in the house and it's working great, except that sometimes when you use a hot water tap elsewhere in the house, that isn't plumbed to the pump, it starts pulsing. It keeps going on and off in one second intervals and has to be switched off.

It's scary, I didn't want to see for how long this can last because I'd imagine it's damaging the pump. The plumber doesn't seem to know what it could be but he's coming over next week to check.

Grundfos suggested that it might be air in the system, but we've had a flange fitted to ensure an air-free supply of hot water and we've done everything they've suggested to get rid of possible air in the pipes. (running hot taps everywhere in the house)

It's early days still but I'm not feeling confident that the plumber will know what to do and was hoping that someone might be able to point us in the right direction.

Thanks!
 
Heres my theory.

When the tap is turned on there is a pressure drop on the tap side of the pump.
The reduced pressure on the tap side causes some water to push through the pump.
The pump is triggered to power on.
Pump is pumping into a closed circuit, so the flow stops and the pump goes off.
The cycle repeats in an oscillation.

I imagine a non return valve fitted prior to the pump would stop the back flow thus stop the pump switching on.
 
Wish I had one, the guy that was sent to do the job doesn't seem to know much about the pumps :(

I just found this in the pump's manual, makes me worried about fitting non-return valves:
" [FONT=&quot]Do not fit non-return valves in the suction line to the pump. Make sure that the pump can vent back to the supply tank."[/FONT]
 
Hi Dannyboy, Any updates with your pump, I have the same problem in my apt. and was told there could be leak somewhere under the floorboards, or behind the walls, as the pump is registering water still flowing even though all the taps switched off. I was going to hire a plumber with one of those cameras to check for underground leaks or should I buy a new pump. Its very annoying the noise, you cant live with it, and its annoying to have to keep switching on it on in order to have a shower too.
 
Aurelia said:
Hi Dannyboy, Any updates with your pump, I have the same problem in my apt. and was told there could be leak somewhere under the floorboards, or behind the walls, as the pump is registering water still flowing even though all the taps switched off. I was going to hire a plumber with one of those cameras to check for underground leaks or should I buy a new pump. Its very annoying the noise, you cant live with it, and its annoying to have to keep switching on it on in order to have a shower too.
Click to expand...

Ours is sorted out, but I'm not sure it's the same problem. Grundfos claim it was starting up because there's air in the system, and some of the pipework was blanked off so there could be air in those pipes, but they're behind tiles now and cannot be reached to release the air. They've suggested putting a non-return valve on the hot water outlet and it's fixed the problem.

The noise is annoying allright, it's fine for the few minutes while you're having a shower, but I couldn't live with that coming on and off at all hours.

Our pump would start up as the hot taps were closed (which aren't pumped) and start pulsing. In other words open up the hot tap, close it abruptly, and the pump comes on. If yours is coming on by itself then it's a different problem.
 
Hi there,

We have had a problem with our Myson shower pump for some time. We turn on the power, step into shower and turn on for the water. We hear a slight noise from pump, but no water from shower. After a short while the pump will kick in and normal service is resumed.
This morning was different, same as above but after lathering no water at all, went out to pump which is located in hot press covered from head to toe in suds and gave the pump a bit of a shake, it then kicked in and resumed shower.
Since then I have tightened up all electrical connections and still same thing is happening. My question is, is there somewhere on the pump where you can apply some WD40 or something similar to stop pump from seizing up?
Thanks.
 
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