Advice needed : Radiators getting hot when systemate is off

Well, this a new problem for me, I noticed in the early hours of the morning my radiators getting hot, really hot. The mechanical clock on the systemate 3 was set not to engage the systemate, (till later in the morning) and the room thermostat wasn't on either which is as expected, yet the radiators were getting hot and the boiler was firing?

Is anyone able to guide me on possible culprits and solutions?

From the symptoms you describe it sounds as though the appliance control board (either a GT155 or GD131 which can be interchanged) is beginning to fail, there are a few things you can do to check if it is going wrong.  This video gives you some idea of what to look for.  It may mention a Boilermate 2000 but the information applies to yours as well.  If you believe the pcb is faulty I can provide a repair or exchange service go to my website for more information https://murraymartin.yolasite.com/  Regards Murray

Hello and thx for the response,

I had hoped I'd fixed it but alas I woke up this morning to no heating and no hot water.  The board shows no life and is clearly not functioning, the question is what's contributed to the board's demise.  Having spoken with Gledhill, the working theory is central heating/main pump has reached the end of its life too.  So I'm looking at a new pump, connecting valves, and a replacement board from you.  Just waiting on a call from my plumber before I commit to a solution.

I have contacted you via your website too murray

regards

Geths

Hi usually if the pump has gone kaput big time then it will usually blow one of the chips at the bottom of the pcb next to the green led next to them, second one up is the boiler circulation pump, next one up is the central heating, the hot water one is the fourth one up (there may or may not be a number 3 some pcbs have them some not). Easy test for a plumber is to put a separate mains feed to the suspect pump and see what it does. To be honest I think I would swap the pcb first before riving any pumps out. Get one from me and I will cover you if it happens to pop a chip if the pump is fritzed. What symptoms made Gledhill think the pump was toast? Regards Murray

ill try to post a picture of the PCB

After a day spent fault finding, I've ordered a new CH/main pump (xb004), pump valves, and a replacement PCB board from Murray.  I can't thank you enough for your assistance today Murray, it's most appreciated.

Geths

Just a little update, the old girl lives! changing the main pump was certainly more difficult than the DHW pump I'd changed previously, mainly due to its placement in the original build/install more than anything else. I also had to substantially alter the mixer valve as the water was scaldingly hot in its previous position. I also took this opportunity to gently flush the system and add a new inhibitor to the sealed CH part.

All this and I'm disabled.  It just goes to show what you can do with some help and guidance.

The heat exchanger plate and store coil (and pipework) are now all that's left of the original construction. Still, she is a spritely 21 years old.

Once again, thank you to Murray and Mike for facilitating this forum

My Systemate 3 was replaced on Tue. Also 21 years old. When they took it outside and layed it on its side there was massive rusting on the underside. You could poke your finger through it. That wasn't the reason for replacing it, but gas man says I've had a lucky escape as could have dumped 115l of water through the house at any time. No way of knowing when in situ either as can't be seen when upright.