Re: Water pump surge damper
- From: "Andy R" <andrewr@xxxxxxxxxx>
- Date: Tue, 4 Nov 2008 13:03:41 -0000
"Chris J Dixon" <chris@xxxxxxxxxxxx> wrote in message
news:0if0h45i45pb382epu2eu05s526j2ousf3@xxxxxxxxxx
Andy R wrote:Understood.
I'm not sure that you have fully understood the problem that I am
"Chris J Dixon" <chris@xxxxxxxxxxxx> wrote in message
news:ef60h4huv60n1pnkooul14hk9gr0gjjcu3@xxxxxxxxxx
My Lunar Stellar has the familiar Truma submersible pump and
onboard adjustable pressure switch.
Clearly it is essential both that the pump switches on and off,
and that it does not chatter.
It seems that it is practically impossible to find a pressure
setting which is OK throughout the voltage range from mains
available, through to battery after a few days' use.
I see that Truma have now produced an electronically controlled
all-in one damper and pressure switch, for the princely sum of
around £80. I guess they have admitted defeat with the old
system.
Whale produce a simple surge damper for around £20. Has anybody
fitted one to a troublesome Truma installation with any success?
The Whale surge dampers simply damp the pulses from diaphragm type pumps.
What they wont do is alter the setting of your pressure switch, so when
the
battery voltage drops to the point where it can't pump hard enough to
reach
the set pressure the pump will still stay on.
Either keep twiddling it manually or spend the £80.
describing.
On opening the tap, pressure falls, the switch closes in response
and the pump starts. The increase in pressure opens the switch,
the pump stops, pressure falls, and so on. The switch can
oscillate several time a second. With other conditions,
something similar can happen on closing the tap.
Try as I might to find a pressure setting which prevents this
condition (whilst still turning on and off correctly), my success
has been limited.
It sounds like the pump's too powerful or the tap's not opening fully.
Alternatively it could be the hysteresis on the switch is insufficient.
Yes, I accept your point that a damper cannot stop the pump
failing to switch off at extreme low voltage. At those times I
wish it was noisier so I could detect it when I am not near the
indicator light.
I bet it it sounds loud in the middle of the night though.
However, I am sure that the damper would significantly improve
the tendency of the system to chatter, which can't be good for
either the pump or the pressure switch. Basic physics at least
indicates that the cycle time would be helpfully lengthened.
If it's a diaphragm type pump the damper will probably help then but if it's
a rotary pump the impact will be less.
I suspect if you could deliver a fairly constant voltage somewhere around 9v
to the pump your probs would be solved as the setting would always be for
this voltage and unless you really flatten the battery you wont go below it.
A circuit something like this
http://www.reuk.co.uk/Zener-Diode-Voltage-Regulator.htm after the switch
would cost a few pence to make and would ensure 9v was delivered to the
pump. It's possible that if the battery drops below about 10.5v the forward
voltage wont be enough to overcome the zener so the power to the pump would
increase to battery voltage but it it should give you an idea of whether it
helps or not. If it does help you could build/buy a better regulator
Rgds
Andy R
.
- References:
- Water pump surge damper
- From: Chris J Dixon
- Re: Water pump surge damper
- From: Andy R
- Re: Water pump surge damper
- From: Chris J Dixon
- Water pump surge damper
- Prev by Date: Re: Water pump surge damper
- Next by Date: Re: Water pump surge damper
- Previous by thread: Re: Water pump surge damper
- Next by thread: Re: Water pump surge damper
- Index(es):
Relevant Pages
|
