Flojet 4405-143 Leak Problem in caravan
Submitted: Friday, Sep 02, 2011 at 18:51
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Geofff
Both pressurised town water and water from our water tanks flows through the 12v pump (not at the same time). When it is turned on and pumping from the tanks (free camps) there is no problem, plenty of pressure and no leaks. However when we hook the hose up to town water in a van park, the pump leaks - the pump is not on in this situation but water flows through it. I think it has some sort of bypass on it but I am no expert.
The pump manual says that the pressure switch max for the pump is 35psi.
Has anyone had experience with this pump? Is the pump faulty? I have tried fitting in-line pressure regulators onto the hose (20psi Bunnings) but it still leaks. I have tried some 15psi pressure regulators and they work and stop the leaks but the water pressure is only a dribble.
This is driving me crazy.......................... HELP!!!
The van is about 10 years old.
Reply By: Member Al (Sunshine Coast) - Saturday, Sep 03, 2011 at 17:19
Saturday, Sep 03, 2011 at 17:19
Geoff, after some research I found info that may help:
1. The Flojet pump is a diaphragm type positive displacement pump. Being of positive displacement design it requires a bypass device to prevent compression damage if the delivery line is shut off. This device is built into the pump and need not concern you.
2. The "35psi pressure switch maximum" is the highest setting that can be made on the pressure switch. It is not the pressure rating of the pump body.
3. I have not been able to find a specification for the maximum pressure that the pump can withstand. The manufacturer of Flojet Pumps does not include this in their specifications, probably because they do not expect the pump to be connected to an external pressure source. However,seeing as how Caravans Plus advise connecting the mains water directly to the pump delivery line I would assume that they consider the pump capable of withstanding mains pressure. Some mains pressures can be quite high and I would not be happy connecting the system without a pressure reducing regulator set to say 35psi.
4. Diaphragm type positive displacement pumps incorporate valves as part of the pumping function. These valves would prevent back-flow and accordingly an external non-return valve would not be necessary.
5. If it were my setup I would not allow connection of the mains water to the pump at all. I would have a manual 2 position change-over valve which connected the system to either the mains or to the pump as I chose. Then there is no issue with back-pressuring the pump.
AnswerID:
464128
Follow Up By: Geofff - Sunday, Sep 04, 2011 at 18:06
Sunday, Sep 04, 2011 at 18:06
Thanks Allan - you're a champion. I value the
information you have given me about the pump.
I think I will follow your suggestions - just need to get a good pressure regulator first - one that controls the pressure when the water is flowing or static.
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Follow Up By: Member Al (Sunshine Coast) - Sunday, Sep 04, 2011 at 20:47
Sunday, Sep 04, 2011 at 20:47
I think a pressure regulator would be a good move Geoff.
Use one set to a little higher than the pump pressure switch or the pump will take precedence on a demand.
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