Requesting help with a systemate 3 fault diagnosis

I'd really appreciate a little help with diagnosing a fault my systemate 3 has developed today.

Regardless of the position of the mechanical clock is in or the room thermostat being at zero.  My systemate 3 is continually sending heat to the radiators?


Any help solving this issue would be greatly appreciated.

Geths

Having spent the night reading previous posts on similar issues and various other sites.   I'm of the thought its the 3-way motorized valve? and it would be a clever move to replace the mixing valve at the same time (prone to scale damage) as it's been compounding the issue somewhat.

I'm not a plumber but have over the years found it nigh on impossible to find a local plumber who has any knowledge of Gledhill stuff. So I often have to fix it myself or at least be able to support my goto plumber in understanding both unit and fault.

Once again any help/advice would be greatly appreciated.

Hi Geths,

This is usually caused by a failure in the PCB in the Systemate. Quite an expensive part to buy new but often second hand PCBs on ebay.

Can also be caused by the motorised diverter valve jamming or failing to fully return to the 'home' position. Check it carefully before buying a new PCB!

Hope that helps,
Mike

Hi Mike,

Firstly thank you for replying. I've said it before but you really are a very kind man. I much appreciate it.

Is there an easy way for me to test/check the valve actuator to confirm it and or the actual mechanical valve is the culprit?

regards

Geths

Hello mike,


1) If I move the bar to the manual position and release it (no heating demand), it returns about halfway between manual and auto, sometimes a tad further but never fully back to auto.

2) If I leave the bar in this middle position and turn the CH on and then a little later turn off the demand, the bar will move alittle further towards auto but not much. If I repeat this test the distance traveled towards auto isn't consistent.

3) If I move the bar to the manual position (with CH on) and release it and turn off the CH, it moves further than the middle point but not all the way back to auto.

If the 'home' position is auto, then it never fully travels to that position.  There feels like little or no resistance between auto and a 3rd of the travel towards manual.

I'm sorry to enquire further but I don't understand what that tells me?

Regards

Geths

Geths wrote:
1) If I move the bar to the manual position and release it (no heating demand), it returns about halfway between manual and auto, sometimes a tad further but never fully back to auto.

Ok, this illustrates the lever does not freely return all the way back to the home position when released, so your diverter valve is sticking. This IS the problem and it needs freeing or replacing.

Just to confirm, try this again with the electricity to the boiler and Systemate turned OFF. If you get the same result, replace the diverter valve, or dismantle and clean it.

Hello Mike,

Performed the same test with no power to the boiler or thermal store and the lever only travels halfway.  While a fault is a fault, I'm grateful its not the PCB (Although MM seems the guy to goto with PCB's)

Did you have any thoughts on my idea of swapping out the blender valve and cleaning/replacing the Y filter when changing the 3-way valve etc?  My systemate III has been up and running for 20 years and when I changed the DHW pump (another fault you helped me diagnose) I changed the valve bodies either side of the pump as they were packed with sludge.

It's not lost on me that you've been assisting/guiding me on and off since 2010! (where does the time go?) and consequently, I've learned so much.  I am so grateful mike, I wish you much good karma in life.

regards

Geths

For any interested readers...

So I drained the heat store and removed the 3-way valve, which was a bit of a bugger to remove, due to its age and the original install.  On inspection, it was clearly knackered, it wouldn't move freely even after spinning it with a drill.   Anyway, installed a new 3-way valve + actuator and took the opportunity to change the Y filter (the filter itself was scaled) and changed the brawa mixer valve (another bugger to remove). While the valve wasn't in terrible condition on inspection, it was certainly reaching the end of its lifespan.  The new one has greatly improved hot-water consistency.   Refilled the system and added a new inhibitor then cleared the system of air and hey presto! shes lives once more.

I found all the required parts at Amazon, Sparesweb, Ebay, and Screwfix and saved a considerable amount on not buying directly from Gledhill.

Thanks again Mike for all your help.