what can be the problem? pulsacoil III; noisey PCB, constant running pump

Hello All,
The LED on the PCB double flashes and a little pause, then double flashes again. Have had the two immerssions changed so we get hot water.Also had a sensor changed and a new flow sensor. The PCB seems to have a buzzing noise from it and when the pump speed is turned down the noise is still present but is reduced but does not fade, and the pump seem to be contantly running,so even if ther isnt a demand for hot water it still runs. It get quiet hot. The engineer tried a new PCB but the fault was still present. Please can someone help. Thanks.[quote]

Hi Andrea

The following information should help you.

1] The Pulsacoil 3 usually has two sensors for the hot water system (depending on exactly which version you have fitted), and either of the sensors could cause this problem.

2] The LED on the pulsacoil 3 should have a single flash that flashes slowly if everything is ok (it's the Pulsacoil 2000 that has a double flash).

3] As for the pump being turned down, the pump should be left on speed number 3 at all times. The pcb controls the speed of the pump by varying the voltage to it, if you turn the speed down it will not work correctly.

Replacing the other sensor in your case should rectify the problem.

Regards
David Hickey
Midland Boilercare Ltd
mailto:service@midlandboilercare.co.uk

Thankyou so much for your advice Mike, the plumber changed the two defective immersion heaters along with rod stats, had 2 new sensors. The pump and board are now very quiet and the led is flashing normally now, but a week later the 2nd green light has gone off and the water is hotter than it first was. The overheat stat has NOT popped out, could the rod thermostat be defective? When a torch was used on the overheat stat it popped out, was reset but still no green light. The led on the pcb is operating correctly. Hope you can help us again really thankfull for this great forum site.

Awaiting your advice.
Thankyou andrea.

Hi Andrea,

Read your post, glad to read it is all fine. Just remember to use the system correctly as this can cause additional faults to occur over a long term. The self check guide may help. You can find it via this link: Pulsacoil 3 Repair