AnswerID: 464128 Submitted: Saturday, Sep 03, 2011 at 17:19
Member Al (Sunshine Coast)
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.
Reply 8 of 9
FollowupID: 738088 Submitted:
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.
FollowUp 1 of 2
FollowupID: 738109 Submitted:
Sunday, Sep 04, 2011 at 20:47
Member Al (Sunshine Coast) posted:
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.
FollowUp 2 of 2