potterton 28i low pressure fault

[judas]

my potterton boiler indicates a low pressure fault when you turn on the hot tap. It preheats the water in the boiler ok but when you turn on the tap the boiler indicates low pressure / pump fault light and water then runs cold. Any suggestions please.

 

[Agile]

It sounds as if you have left the filling valve open!!!

Tony

 

[judas]

the filling valve for the central heating is shut it is the hot water side i am having snags with dont think that has a filling valve.

 

[powell30]

What agile means is that without sufficient pressure in the primary system the boiler will report a low pressure fault......ie primary water heats up your cold water via the secondary plate heat exchanger........either fill your rad side up or shut off the filling loop (it maybe letting by) or trace a leak or check the prv........all main system side....nothing to do with your hot water

 

[baxpoti]

What is the pressure gauge reading and does it fluctuate?

Probably a worn primary flow switch

 

[gasinstaller]

is the presuure gauge is rising when you switch the heating on ?
Could be the expanssion vessel. seen it loads of times when the heating is not used in the summer they dont realalize whats happening. could also be the pump on the way out.

All combis work the same way

Open tap or turn CH on.
1. pump runs
2. activates pressure switch
3. Fan runs
4. activates air pressure switch
5. Gas valve opens
6. ignition
7. Temp read by thermistors controlls the time gas valve stays open

so it could be the pump.

Call an engineer

 

[Agile]

the filling valve for the central heating is shut it is the hot water side i am having snags with dont think that has a filling valve.

How do you know that the filling loop valve is actually closed?

What is the system pressure when the boiler is resting?

What is the system pressure when you turn on a hot tap?

Tony