Have been putting up with a problem for too long and am too tight to buy a new pump as i suspect there isn't much wrong with this one.
Its a Davey XP500H with a hydrascan control unit.
It started playing up ages ago when it wouldn't always kick in when you turned a tap on.
I spoke to a friend in the pump industry and he said it needed a new control unit and gave me a new one.
Didn't fix it.
Sometimes it starts, sometimes it don't and i can't pick why.
I suspect the diaphram in the air tank as it doesn't hold pressure like it should.
My friend says with the control unit he gave me the air tank is now redundant and it shouldn't matter.
the pump works fine when it starts.
I can't find any leaks in the lines pre or post the pump.
basically i am at a loss.
I am tempted to buy a new one and keep this as a spare but they aren't cheap.
Any hints would be appreciated.
Water pump headaches(13 posts) (11 voices)
Hi guys,Posted Saturday 10 Apr 2010 @ 5:22:39 am from IP #
Check the bladder is at the right pressure - if it is still in use.
and there is an article on another forum mentioning this about the sensor needing a clean.
"We are are davey pump dealer and see this problem every now and again where a pump won't start up all the time. With the hydrascans there is a sensor plate on the inside of the hydrascan which can be accessed by unscrewing the cap on top of the hydrascan. This plate can get muddy/dirty/grubby with age and will sense less and less as it does. To counter act this just give it a clean with a tooth brush or something that will fit in it and you should be right to go."
Trust it helps.Posted Sunday 11 Apr 2010 @ 12:35:49 am from IP #
I have a new control unit in place now and the same problem exists.
It doesn't make sense.
If there was a slow leak on the downstream side i could almost understand it but it can happen when you only used the tap a couple of minutes ago. I get up first in the morning and sometimes the pump will start sometimes not.
I might pull this control unit to bits and see if there is a sensor to clean.
thanks for your help.
BomberPosted Saturday 17 Apr 2010 @ 1:41:27 am from IP #
Of course another possibility is it isn't the sensor at all, but maybe a faulty motor.
This can happen with one open circuit winding or a damaged comutator, which causes a restart problem when it happens to stop right on the faultly bit. Sometimes on-off-on-off moves it enough to kick into action again.
If your motor gets plenty of use or is older, it might be just worn out brushes or comutator, or simply an o/cct winding problem which won't fix itself no matter how many times you change the controller.
Check the motor, then buy a new one.Posted Tuesday 20 Apr 2010 @ 5:58:51 am from IP #
If you are still having problems with pump, it could be an impeller problem. This is one of the reasons Hydrascan stops automatic cut in when water pressure drops. Works if you turn pump on off at power supply, but won't restart on its own. Low pressure indicator light comes on. see primopumps.com websitePosted Thursday 1 Jul 2010 @ 6:05:43 pm from IP #
I have an xp900h with a hydrascan fitted. I have been having the same problem over quite a long period. I have been just hitting the reset button to get it going again, however lately it is happening more frequently. Yesterday, I unscrewed the cap on the hydrascan unit and then just switched on the power for a fraction of a second. A jet of water came out of the hydrascan. I did this a couple of times. This appears to have had some effect as the pump hasn't stop since altho it is only a short time. After reading the info at primo pumps, I also raised the cut in pressure by turning the adjusting screw quarter turn clockwise. The pump now cuts in quicker after turning on the tap which may also help. Flushing the hydrascan should have cleaned it, but if I have any more trouble I will try cleaning it with a toothbrush as suggested.Posted Tuesday 13 Jul 2010 @ 12:42:11 am from IP #
Update on pump problem davey xp900h:-
Hydrascan unit is ok. The red light came on when pump wouldn't start indicating low pressure and sensor working correctly. I have changed the starting capacitor on the motor and this seems to be the fix. When you talk to a few people this is quite common. The old capacitor was measuring only 6.7uf although marked as a 12uf. Capacitors deteriorate with age. It was very easy to fix. Just remove the cover and plug in the new one after unplugging the existing unit. Cost $12 from an electrical supplier.
Pump seems to be stronger and more quiet in operation also.Posted Thursday 15 Jul 2010 @ 6:04:29 am from IP #
Had a similar problem with a davey xp500H. Air pressure was fixed earlier including seals replaced. And pump wouldn't always kick on when the pressure dropped. One of the defining things that made me twig was that when it wouldn't kick on the pump would hum as though it was trying to turn on. Being a capacitor start motor they need the capacitor to work as part of the starting circuit. Normally (in my experience) the capacitor is a catastrophic failure item - not an intermittent failure. To cut a long story short, swapped out the capacitor (instead of replacing the hydrascan with a torium) and I have a working pump for 1/10th of the cost of the recommended repair. I would work on the assumption is that if you can hear it trying to start, swap the capacitor before upgrading the electronics unit. Btw - there are wires which carry electricity in there - know what you are doing before you try it!Posted Wednesday 29 Sep 2010 @ 10:23:12 am from IP #
Hi I have a pump that turns on every 20sec for 4sec and this happens all the time. We had a pump guy look at it and he replaced the sensor unit the first time the had to return and replace the pressure bowl and the problem continues. Any suggestion as this is becoming an expensive exercise if he has to Coe out yet again. I have checked for leaks and also for dripping taps cheers Chris.Posted Tuesday 9 Jul 2013 @ 6:19:31 am from IP #
The main obvious reason for this is that the system pressure is dropping, triggering the pump to repressurise. This could be because water is leaking back through the pump, it should have a valve in there that stops that, so this could be leaking. You don't say if this is part of a rainwater/mains water changeover system. If so, the system may also be leaking tank water under pressure into the mains, if the mains pressure is particularly low and you have a faulty valve on the mains.
Sounds to me that the pump guy doesn't know what he is doing and is just grasping at straws. The best way to check what's happening is a pressure gauge on the tank or pump outlet, this will tell you if the pressure is cycling or if there is some sort of weird controller fault.Posted Tuesday 9 Jul 2013 @ 11:52:18 am from IP #
Are the pressure settings adjustable?
Could be that the gap between pump turn off and on is too fine, perhaps there is some pipe or hose on your system that is flexing under pressure. Try adjusting the set pressure for the pump to turn back on down some, or upping the high pressure setting a bit.Posted Tuesday 9 Jul 2013 @ 2:18:15 pm from IP #
Christarawa, I had that problem with a small caravan-style pump. Checked for leaks and drips in the plumbing, tried a different pressure tank etc. In the end I replaced the pump. The pump seemed to be faulty - leaking back through itself, losing pressure!Posted Wednesday 10 Jul 2013 @ 2:58:44 am from IP #
I have been putting up with the Davey Hydrascan problems for years, and I finally did something about it!
The Hydrascan is far too clever for its own good.
It has an amazingly complex system of sensors and electronics which is probably wonderful idiot-proofing if your pump really needs protecting from lack of water …
If your pump cannot run out of water, then you can dispense with all the complexity.
I have just solved my Hydrascan problems completely!
I pulled the Hydrascan apart, and removed all the tiny wires and the circuit board.
This left me with just a simple micro-switch, operated by the pressure cylinder and its adjustable spring!
It's a mini micro-switch, with very small terminals, and it was obvious that they had been making intermittent contact with the little spade connectors… Could have been the problem all along !!!
I rearranged the wiring so the micro-switch now just breaks the Active, and soldered those wires to the micro-switch.
Done! Finished! Working like a dream! It is now just a simple Pressure Switch!
The only thing that can possibly wear out now is the micro-switch, and it is really easily replaced.Posted Monday 2 Nov 2015 @ 12:32:08 am from IP #
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