Re: Manual Override Switch Tripping

Good morning,

Please help save my Christmas!!!

A week ago today the boiler completely shut down. I found a leak from the higher 90 degree shut off valve which is directly above the boiler pump (bottom of the three). An electrician diagnosed that this pump needed replacing. This was done and with the change of a fuse on the PCB the system was restored. Naturally thinking that it would just take time to warm up it was left on an overnight basis.

However, the following day I noticed that the manual override switch had popped out and the sensor temperatures were right down. Right now they are at T1 - 23, T2 - 15 and T3 - 15. I ran the diagnostic check and everything reported as fine and no sensor errors, all LED's etc.

When the reset switch is pressed the system starts sounding like it is trying to pump water round and gives a fizzing noise. I saw someone mention in a previous topic that it's the noise of air being heated but I'm not sure. Then after about 10 seconds of doing that the noise changes to a rushing of water through the pipes and then about 4 or 5 banging noises. Then the override switch activates again.

Given a boiler pump was fitted could it be that air is stuck within the system; within the heat exchanger or dual heating element, or is the system designed to relieve itself of air? I know there is an automatic vent at the top which seems to be working fine as there is the noise of escaping air from it every now and again. I've taken the top off this and the ball in the value is moving freely.

Before I call someone out I just want to make sure there's nothing I could do to rectify the issue. I notice a couple of drain off taps and was wondering if they could be the answer?

Any help/advice that could be provided would be greatly appreciated.

Thanks in advance.

The fizzing noise sounds like the pump below has got wet when the water dripped onto it.
Or you could have air trapped.
To deal with the air problem.
Look at your manual and go through the commissioning section.
As if you have just installed the unit.
Mike
MGC/H2O
Norfolk

Thanks for the reply, but I have a little update to provide.

After carrying out testing of the board I have realised what the issue is. When I installed the new boiler pump and changed the fuse on the PCB, I had noticed that the white relay (Filtana FS 800 2147) directly above the fuse flashed brightly when it was first turned on. I thought nothing of it at the time.

However, when the water temperature drops below 55 degrees and the board effectively tells the boiler pump to switch on, there is no power from the board down to the pump. Therefore, this is why the heating element (bottle) is fizzing, overheating and tripping the override; as the hot water is not being pumped into its storage.

I have figured the PCB to be the problem as if the boiler pump is connected to the heating pump on the PCB, and the heating is turned on at the control panel on the wall, then when the reset button is pressed the water heats up into the storage as it should and I get perfectly hot water and heating (when the heating pump is connected again obviously!). It's a bit of a faff but it's a great emergency resolution.

Anyway, I can only assume that the white relay has blown and therefore not sending a current to the boiler pump when meant to. So, a new PCB it is.

I've checked (which involved a whole lot of smelling!) the whole circuitry for signs of burning and nothing. I'm a little nervous about spending £130 on a new board as it could blow just the same as it has already. My thought is that when the water first shorted the boiler pump it has back fed to the board and caused the damage...I hope! So now the boiler pump and leak have been sorted there should be no issue. Having said that, might be cheaper in the long run to have someone checking it over.

Any thoughts and advice about buying a new board and plugging it straight on would be most welcome.

And I hope this post will be useful to others having the same difficult time as me.

Thanks.

Well to give you an example.
On the Pulsacoil 2000 units.
I have been to them where the PHE has leaked onto the DHW pump.
Upon fitting a new pump and switching on the pump drive board just burns out in the top left hand corner.
This happen whether the fuse on the board has blown or not.
I would say your problem started when the pump got wet.
Mike