Surging Pressure Washer
I have a KEW Hobby pressure washer ...... been great to date ... but
yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing .... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. |
Surging Pressure Washer
"Rick Hughes" wrote in message ... I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. Probably a blockage on the inlet side. Mike |
Surging Pressure Washer
On 01/05/2011 15:50, Rick Hughes wrote:
I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. At what rate is it surging - like several times per second, once every few seconds, etc.? During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? [Anyone know how many pistons a typical pressure washer has in its pump, and what the rotational speed is likely to be?] -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Surging Pressure Washer
Rick Hughes wrote:
I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. I had a similar problem with a Karcher - and prodding some grit out of the jet with the provided 'prodder' did the trick. -- Kev |
Surging Pressure Washer
"Roger Mills" wrote in message ... At what rate is it surging - like several times per second, once every few seconds, etc.? equal pressure / no pressure ... about 2 sec on 2 off or maybe a little less. During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? Motor running contiuously When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? Never done that ... iut would just run up to load and motor stay at load, never cut/in out. (Hobby 88 is model) sound wouldof course change, but does not stop running. |
Surging Pressure Washer
"Ret." wrote in message ... Rick Hughes wrote: I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. I had a similar problem with a Karcher - and prodding some grit out of the jet with the provided 'prodder' did the trick. Changed lance to scrubber unit ... still the same, so not related to hose or lance. |
Surging Pressure Washer
On 01/05/2011 18:24, Rick Hughes wrote:
"Roger Mills" wrote in message ... At what rate is it surging - like several times per second, once every few seconds, etc.? equal pressure / no pressure ... about 2 sec on 2 off or maybe a little less. During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? Motor running contiuously When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? Never done that ... iut would just run up to load and motor stay at load, never cut/in out. (Hobby 88 is model) sound wouldof course change, but does not stop running. Hmmm, the ones i've used have all (okay all four different ones) cut the motor whenever there is no flow. Pull the trigger, the motor starts up, release the trigger, the motor stops. SteveW |
Surging Pressure Washer
On 01/05/2011 15:50, Rick Hughes wrote:
I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? Only about 30 years worth :-) Made my living selling them for years. No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. Penny to a pinch of poo its a partial blockage in the nozzle. Don't be too forceful in trying to clear it, nozzles are fairly delicate. Blow it backwards with an airline if you can. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 01/05/2011 16:55, Roger Mills wrote:
On 01/05/2011 15:50, Rick Hughes wrote: I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. At what rate is it surging - like several times per second, once every few seconds, etc.? During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? [Anyone know how many pistons a typical pressure washer has in its pump, and what the rotational speed is likely to be?] Almost all have 3, they are generally axial swash plate pumps. Motor speed around 2800 rpm. Cheap ones have universal motors that run really fast. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 01/05/2011 19:39, Steve Walker wrote:
On 01/05/2011 18:24, Rick Hughes wrote: "Roger Mills" wrote in message ... At what rate is it surging - like several times per second, once every few seconds, etc.? equal pressure / no pressure ... about 2 sec on 2 off or maybe a little less. During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? Motor running contiuously When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? Never done that ... iut would just run up to load and motor stay at load, never cut/in out. (Hobby 88 is model) sound wouldof course change, but does not stop running. Hmmm, the ones i've used have all (okay all four different ones) cut the motor whenever there is no flow. Pull the trigger, the motor starts up, release the trigger, the motor stops. The KEW Hobby was one of the first on the market, IIRC it had a bypass valve rather than a pressure switch which most modern machines use. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
"The Medway Handyman" wrote in message ... On 01/05/2011 19:39, Steve Walker wrote: The KEW Hobby was one of the first on the market, IIRC it had a bypass valve rather than a pressure switch which most modern machines use. That would tie in with the in-use sound ..you can hear pump getting up to pressure, and if you are 'jetting' it is one, sound, when you release the trigger, sound changes as I presume it reaches peak pressure and 'by pass' opens ... but certainly does not stop running. |
Surging Pressure Washer
"The Medway Handyman" wrote in message ... Penny to a pinch of poo its a partial blockage in the nozzle. Don't be too forceful in trying to clear it, nozzles are fairly delicate. Blow it backwards with an airline if you can. nope ... I took lance off and fitted a patio scrubbere - exactly the same surging, so not nozzle related. I also have a separate nozzle (rotating) tried that ... same surging. Tech spec 80bar 1.3 hp nozzle pressure 88 bar most other specs are about hose size & dimensions etc. |
Surging Pressure Washer
On 01/05/2011 18:25, Rick Hughes wrote:
"Ret." wrote in message ... Rick Hughes wrote: I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. Try it without the lance. Do you get a steady stream of water? If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. I had a similar problem with a Karcher - and prodding some grit out of the jet with the provided 'prodder' did the trick. Changed lance to scrubber unit ... still the same, so not related to hose or lance. In that case it sounds like the by pass (or unloader) valve is out of kilter. To explain whats occurring; Say the working pressure is 100 bar. The by pass valve is basically a piston held shut by a spring. When the trigger is closed the back pressure rises to say 105 bar and forces the valve open - allowing water to flow back into the inlet & round in a continuous loop. When the gun is opened the pressure against the spring drops allowing the valve to close. A partial blockage in the nozzle would cause the back pressure to rise & operate the valve, the pressure drops so the valve closes, the pressure rises & the valve opens, etc etc etc. If the valve is out of kilter (or the spring has broken) - e.g. set too low - it causes exactly the symptoms you describe. Page 5 part 60 here; http://www.dolmar.nl/images/files/tekeningen/HP11.pdf Spring pressure needs increasing 'very slightly'. Or a new valve. p.s. Not using Hozelock 'Waterstop' connectors by any chance? -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 01/05/2011 19:39, Steve Walker wrote:
On 01/05/2011 18:24, Rick Hughes wrote: "Roger Mills" wrote in message ... At what rate is it surging - like several times per second, once every few seconds, etc.? equal pressure / no pressure ... about 2 sec on 2 off or maybe a little less. During this pressure fluctuation, is the motor running all the time - or does it keep starting and stopping? Motor running contiuously When you fist turn it on with the outlet closed (i.e. trigger on lance not operated) does get up to pressure and then cut the motor, like it's supposed to? Never done that ... iut would just run up to load and motor stay at load, never cut/in out. (Hobby 88 is model) sound wouldof course change, but does not stop running. Hmmm, the ones i've used have all (okay all four different ones) cut the motor whenever there is no flow. Pull the trigger, the motor starts up, release the trigger, the motor stops. I have a Karcher and the motor keeps running. OK, it is quite old - cylinder rather than upright. -- Old Codger e-mail use reply to field What matters in politics is not what happens, but what you can make people believe has happened. [Janet Daley 27/8/2003] |
Surging Pressure Washer
"The Medway Handyman" wrote in message ... Page 5 part 60 here; http://www.dolmar.nl/images/files/tekeningen/HP11.pdf Spring pressure needs increasing 'very slightly'. Or a new valve. p.s. Not using Hozelock 'Waterstop' connectors by any chance? Great explanation .,.. I am away for a few days with work ... will take a look, maybe a clean will fix :-) Don't suppose you have same parts list / drawings for the Hobby 88 ? It is a rectangular box type, rather than upright. |
Surging Pressure Washer
On 01/05/2011 20:14, The Medway Handyman wrote:
On 01/05/2011 15:50, Rick Hughes wrote: I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? Only about 30 years worth :-) Made my living selling them for years. No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. Penny to a pinch of poo its a partial blockage in the nozzle. Don't be too forceful in trying to clear it, nozzles are fairly delicate. Blow it backwards with an airline if you can. OK, how about this for a theory . . He says that water flows through ok at mains pressure with the pump not running, so there isn't a conventional blockage in the pipework. He says that two different nozzles behave the same, so it's unlikely that they're *both* blocked. I reckon that the lining of the pressure hose is de-laminating, and cutting off the flow. Then the by-pass opens and releases the pressure, the pressure hose recovers for a bit and lets through another pulse - and then the whole thing repeats on a once per 4 second cycle. Got to be something like that! -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Surging Pressure Washer
"Roger Mills" wrote in message ... I reckon that the lining of the pressure hose is de-laminating, and cutting off the flow. Then the by-pass opens and releases the pressure, the pressure hose recovers for a bit and lets through another pulse - and then the whole thing repeats on a once per 4 second cycle. OK ... the pressure hose is in s**t order, outer covering all peeling off, so inner could be crap. It was going to be changed this year. I don't have a spare hose to try though ... so that limits my next step |
Surging Pressure Washer
On 01/05/2011 20:58, Roger Mills wrote:
On 01/05/2011 20:14, The Medway Handyman wrote: On 01/05/2011 15:50, Rick Hughes wrote: I have a KEW Hobby pressure washer ...... been great to date ... but yesterday started surging. This is significant enough to make it useless, almost equal cadence between pressure & no pressure ... the outlet pressure gauge is also reading nothing ... but that may be just a duff gauge. Anybody any experience with pressure washers ? Only about 30 years worth :-) Made my living selling them for years. No shortage of incoming mains (pressure or flow rate) even tried different hoses & fittings to be 100% sure of that. If I operate lance without unit being switched on ... water is jetting out OK. Plus when it 'surges' it does seem right pressure and flow at the peak of each surge. Penny to a pinch of poo its a partial blockage in the nozzle. Don't be too forceful in trying to clear it, nozzles are fairly delicate. Blow it backwards with an airline if you can. OK, how about this for a theory . . He says that water flows through ok at mains pressure with the pump not running, so there isn't a conventional blockage in the pipework. He says that two different nozzles behave the same, so it's unlikely that they're *both* blocked. I reckon that the lining of the pressure hose is de-laminating, and cutting off the flow. Then the by-pass opens and releases the pressure, the pressure hose recovers for a bit and lets through another pulse - and then the whole thing repeats on a once per 4 second cycle. Got to be something like that! Could well be Roger. Although I would expect the delaminating hose would has caused a blockage in the nozzle. My current money is on the by pass valve. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 01/05/2011 20:55, Rick Hughes wrote:
"The Medway Handyman" wrote in message ... Page 5 part 60 here; http://www.dolmar.nl/images/files/tekeningen/HP11.pdf Spring pressure needs increasing 'very slightly'. Or a new valve. p.s. Not using Hozelock 'Waterstop' connectors by any chance? Great explanation .,.. I am away for a few days with work ... will take a look, maybe a clean will fix :-) Don't suppose you have same parts list / drawings for the Hobby 88 ? It is a rectangular box type, rather than upright. That would make it pretty old. They may well have used the same design unloader/by pass on the newer models though. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 03/05/2011 23:46, John Rumm wrote:
What happens if you disconnect the pressure hose and let water squire out the output spout - does it still surge? I'm not sure that would tell you very much, because it wouldn't be able to produce any back pressure. I would expect it to pee water out continuously even if (say) the by-pass valve were faulty. -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Surging Pressure Washer
On 04/05/2011 17:56, Roger Mills wrote:
On 03/05/2011 23:46, John Rumm wrote: What happens if you disconnect the pressure hose and let water squire out the output spout - does it still surge? I'm not sure that would tell you very much, because it wouldn't be able to produce any back pressure. I would expect it to pee water out continuously even if (say) the by-pass valve were faulty. It would confirm the supply is adequate. -- Dave - The Medway Handyman www.medwayhandyman.co.uk |
Surging Pressure Washer
On 05/05/2011 18:40, The Medway Handyman wrote:
On 04/05/2011 17:56, Roger Mills wrote: On 03/05/2011 23:46, John Rumm wrote: What happens if you disconnect the pressure hose and let water squire out the output spout - does it still surge? I'm not sure that would tell you very much, because it wouldn't be able to produce any back pressure. I would expect it to pee water out continuously even if (say) the by-pass valve were faulty. It would confirm the supply is adequate. But the OP has already said that he gets good flow (without a nozzle) when operating the trigger without switching the machine on - as one does to purge the pipework of air. -- Cheers, Roger ____________ Please reply to Newsgroup. Whilst email address is valid, it is seldom checked. |
Surging Pressure Washer
On Sun, 01 May 2011 20:47:52 +0100, The Medway Handyman wrote:
p.s. Not using Hozelock 'Waterstop' connectors by any chance? Just read through the thread, I still have a very old KEW Hobby, bought at the Ideal Homes Exhibition many many years ago. I also had this problem, and in the end it turned out to be using waterstop connectors on the inlet. Also had trouble with grit in the lance, had to buy a new lance, as the old one didn't lend itself to my style of DIY disassembly! :-) Still in the garage unused now as it was bl**dy heavy to lug around, now replaced with a Nilfisk. -- The Wanderer An expert is someone who has made all the mistakes which can be made, in a narrow field. |
Surging Pressure Washer
On Thu, 5 May 2011 20:12:23 +0100, The Wanderer wrote:
p.s. Not using Hozelock 'Waterstop' connectors by any chance? I also had this problem, and in the end it turned out to be using waterstop connectors on the inlet. I can't work out why waterstop connectors are supposed to be a problem or if they are how. When connected the male spigot physicaly pushes the valve open, no way can it be sucked shut. Maybe some people put waterstops at both ends of the hose and the one at the tap end is sucked too far open blocking the flow? Easy cure for that... -- Cheers Dave. |
Surging Pressure Washer
On Thu, 05 May 2011 22:26:23 +0100 (BST), Dave Liquorice wrote:
On Thu, 5 May 2011 20:12:23 +0100, The Wanderer wrote: p.s. Not using Hozelock 'Waterstop' connectors by any chance? I also had this problem, and in the end it turned out to be using waterstop connectors on the inlet. I can't work out why waterstop connectors are supposed to be a problem or if they are how. When connected the male spigot physicaly pushes the valve open, no way can it be sucked shut. On the face of it, I've got to agree with you, there shouldn't be a problem. Except that from personal experience I can say there is! I can only think that the whole arrangement (the spigot, the rubber seal, the actual clearance when open) restricts the flow into the pump. -- The Wanderer Meditate! It's better than sitting doing nothing. |
Surging Pressure Washer
"Dave Liquorice" wrote in message ll.co.uk... On Thu, 5 May 2011 20:12:23 +0100, The Wanderer wrote: p.s. Not using Hozelock 'Waterstop' connectors by any chance? I also had this problem, and in the end it turned out to be using waterstop connectors on the inlet. I can't work out why waterstop connectors are supposed to be a problem or if they are how. When connected the male spigot physicaly pushes the valve open, no way can it be sucked shut. Maybe some people put waterstops at both ends of the hose and the one at the tap end is sucked too far open blocking the flow? Easy cure for that... Have to agree on that they are not flow related when connected, as you say they are physically open when connected, irrespective of water. |
Surging Pressure Washer
"Roger Mills" wrote in message ... On 05/05/2011 18:40, The Medway Handyman wrote: On 04/05/2011 17:56, Roger Mills wrote: On 03/05/2011 23:46, John Rumm wrote: What happens if you disconnect the pressure hose and let water squire out the output spout - does it still surge? I'm not sure that would tell you very much, because it wouldn't be able to produce any back pressure. I would expect it to pee water out continuously even if (say) the by-pass valve were faulty. It would confirm the supply is adequate. But the OP has already said that he gets good flow (without a nozzle) when operating the trigger without switching the machine on - as one does to purge the pipework of air. -- Yep to be 100% sure ... connect up water hose, operate lance trigger but leave pump 'off' get continuous low of water, reaches about 30' |
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