Water pump running continuously, but . . .

[LittleSister]

Ok, I've read various other posts on the topic, and it seems this can be caused by pretty much anything that could possibly go wrong with a pumped water system, but I'm very much up against it, and my specific symptoms may enable the cognoscenti to home in on the actual (or at least most likely) cause of my problem, rather than just throw up random possibilities.

When turned on, the pump runs as normal (as if one had run a tap) for a few moments, then instead of turning off, suddenly slows to perhaps half(?) speed and keeps going like that.

I recently had the calorifier pressure valve fail. It may have been (I can't now be certain) that the pump was then running continuously at 'normal' high speed, and not 'stepping down' as it now is .

As fixing the calorifier is an ongoing, and very frustrating, saga, I have now cut that out the the system and have only the cold side of the system connected.

I found a small leak from the outlet of the water pump, and assumed that was the problem, but that is now fixed and there is no change. Inhale searched the rest of the system (as far as is visible) and haven't found further leaks.

Over to you!

 

[mrangry]

I had this issue with an old par max pump and it was the micro switch which was faulty. I replaced the micro switch and it worked for a short time but ended up just replacing the pump and realised how efficient and quiet a modern replacement pump could be.

Was the calorifier pressure relief valve faulty, or was the system running at higher that normal pressure?

 

[Sticky Fingers]

Empty tank causes this.

 

[LittleSister]

Empty tank causes this.

The tank is almost full, and there's plenty of water coming out of the (cold only) taps when I turn them on.

I had this issue with an old par max pump and it was the micro switch which was faulty. I replaced the micro switch and it worked for a short time but ended up just replacing the pump and realised how efficient and quiet a modern replacement pump could be.

Was the calorifier pressure relief valve faulty, or was the system running at higher that normal pressure?

If the micro-switch was faulty, wouldn't this fail to either turn on or turn off the pump, rather than have it run ay half-ish speed after a few moments? On the other hand, if it was failing to turn off, perhaps it is running at full pelt while it is pumping water along until it reaches normal pressure, then running more slowly as the motor is spinning in stationary water that has nowhere to flow?

 

[LittleSister]

Was the calorifier pressure relief valve faulty, or was the system running at higher that normal pressure?

There's an idea! (I missed this on first reading, in a rush.) An appealing one, too. Getting the old valve out is proving very challenging and very time consuming.

In my experience having two different, seemingly unrelated problems at once is often actually two symptoms of the same underlying problem once I finally see the connection (or, they're actually genuinely unrelated and coincidental ).