Hi again everyone I appear to have an air leak coming from my on-off control box which I have replaced and the problem continues, when I say a leak it seems as if the pipe is letting through air all the time I can hear it hissing all the time until it reaches pressure and cuts out then it is quiet does an obvious solution spring to mind thanks Chris
- Thread starter chrisf1
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rtbcomp
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If it was the NRV it should still leak after the motor switches off.
Sounds more like the unloading valve or a leak at where the pipe joins it. When the pump stops the unloader will release the pressure in the delivery pipe, therefore no more hissing.
Sounds more like the unloading valve or a leak at where the pipe joins it. When the pump stops the unloader will release the pressure in the delivery pipe, therefore no more hissing.
the snooper
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as rtb has said it could be the non return if it is it will still come from the unloading valve as it will be leaking back into the delivery pipe
so as rtb says does it still leak after comp has switched off
so as rtb says does it still leak after comp has switched off
Hi and thanks for the reply, as I first said when that pump reaches pressure and cuts off the hissing stops. I have replaced the on off switch and all the joints are sealed and still have the same problem, when it cuts out after reaching pressure the hissing noise does not change it ceases a second or 2 after the pump stops I will attempt to send a picture tomorrow and that might be more help thanks Chris
The problem can only be due to two things, the non return valve or the unloader valve.
On a tandem unit there will be a common unloader valve which is part of the pressure switch unit, you have replaced that so logically thats ruled out. Each pump will have it's own NRV, which is attached to the tank at the end of the feed pipe from the pump.
You have also replaced those which should logically rule them out but it's not unknown for new parts to be faulty.
Each NRV should be connected to the unloader via a small bore tube through a one way valve, so it should be possible to check each NRV by disconnecting, electrically, each pump in turn. If the the hissing stops with either of the pumps disconnected then the faulty NRV will be revealed. If the configuration is as I assume it to be above.
On a tandem unit there will be a common unloader valve which is part of the pressure switch unit, you have replaced that so logically thats ruled out. Each pump will have it's own NRV, which is attached to the tank at the end of the feed pipe from the pump.
You have also replaced those which should logically rule them out but it's not unknown for new parts to be faulty.
Each NRV should be connected to the unloader via a small bore tube through a one way valve, so it should be possible to check each NRV by disconnecting, electrically, each pump in turn. If the the hissing stops with either of the pumps disconnected then the faulty NRV will be revealed. If the configuration is as I assume it to be above.
