shower pump "hunting" when the bath tap is run

[Gettinthebug]

WTF is going on here?
Does it need bleeding of air somehow? or is the pump faulty?......It seems not to do it when the shower is turned on

 

[RF Lighting]

What is it hunting for?

 

[ban-all-sheds]

The Queen of Spades?

Although I note that the Wikipidia article on Hearts doesn't list that alternative name, and I doubt an edit would be welcome....

 

[Richard C]

It’s impossible even to attempt an answer based on so little information. If you’d care to expand a little about the system you have, how old it is & under precisely what circumstances it happens maybe we can.

 

[Gettinthebug]

It’s impossible even to attempt an answer based on so little information. If you’d care to expand a little about the system you have, how old it is & under precisely what circumstances it happens maybe we can.

Thanks for at least one sensible reply
ok the pump supplies the shower only and not any of the other hot water The pump is a standard one of these types and nothing special Salamander is the make. When activating the shower, the pump (in the airing cupboard) does the normal continuous whooshing sound. However when the shower is off but you run the hot water tap in the bath the pump "hunts" it kind of has a pulse - on off on off kind of thing.........actually its bl**dy difficult to put into words. I thought hunting was an acceted expression in the plumbing world of pumps.......anway its the same as when you switch off a cars ignition but the ignition is too far advanced you get "hunting".

 

[electronicsuk]

ok the pump supplies the shower only and not any of the other hot water

However when the shower is off but you run the hot water tap in the bath the pump "hunts" it kind of has a pulse - on off on off kind of thing.........

The two statements above seem to be the important factors. I suspect what you have is a negative head shower pump, in which the pump should be activated by the drop in pressure at the pump outlet when (in this case) the shower valve is opened. However, it seems that when you are running your hot taps, despite them not being on the outlet of the pump, the pump is seeing a decrease in pressure at the inlet that's large enough to activate the pressure switch.

If this is indeed the case, either try fitting a non return valve right before the pump hot inlet or, if there is no reason for a negative head pump to be fitted, install a standard pump that relies on flow rather than pressure switches.

 

[Richard C]

Well you gave so little info, the other guys were just having a bit of a grin which is maybe to be expected, I'm not always sensible myself Your lucky you didn't get the crystal ball - now who did that & what happened to them?

Hunting can mean many different things; what I think is happening in your case is that the pressure in the pumped shower line is dropping when you run the bath tap sufficiently to continually trigger the pump pressure flow switch, hence the hunting.

More questions; where is the HW take off for the pump, does it share the HW feed off the top pf the HW cylinder to the bath? Do you have a proprietary flange or is it just tees off? What type of Salamander pump exactly do you have?

 

[Richard C]

Beaten to it

 

[electronicsuk]

Well you gave so little info, the other guys were just having a bit of a grin which is maybe to be expected, I'm not always sensible myself Your lucky you didn't get the crystal ball - now who did that & what happened to them?

I think it was RF. In any case, here it is:

 

[Richard C]

But he's still around isn't he Brilliant; always made me chuckle

 

[electronicsuk]

But he's still around isn't he

Yup.

 

[Richard C]

But he's still around isn't he

Yup.

So why no crystal ball for such a long time? I'm tempted to steal it

 

[Taylortwocities]

He is more or less retired now - replaced by

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• Taylortwocities
• 2 Jan 2010
• 22

 

[ban-all-sheds]

I quite liked his young assistant, but mean old spoilsport moderator thinks she isn't seemly.

 

[BournemouthPlumber]

If this is indeed the case, either try fitting a non return valve right before the pump hot inlet or, if there is no reason for a negative head pump to be fitted, install a standard pump that relies on flow rather than pressure switches.

If you do that you will be breaching manufacturers instructions and liable to damage the pump as you will prevent expansion. It is OK to fit NRV's to the outlet side of the pump - but not the inlet.

Please be careful about the advice you give on here as that directly contradicts express instructions from Salamander.

See point 5 below taken from the salamander installation guide.

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• BournemouthPlumber
• 17 Jul 2010
• 2