Gabarron Electric Central Heating boiler CMX15

Alan-N · Apr 22, 2022

Got called to look at a Gabarron CMX15 that was dead, discovered the Safety Limiter device on the CH side had tripped, reset it and bled the radiators are recharged to 1.5bar per the manual. long story short it has tripped a couple of times since. Done it today while I was there after only being powered up for 5 minutes, the water was stone cold and the Sr value was 18 (from the diagnostic routine) , it also this time refused to reset even with the mains power off. In my mind the device itself is faulty. I did call Elnur UK but the bloke didn't seem to have a clue and wanted me to send him all the details in an email, never got any reply. Am I missing any other reasons for that switch to keep tripping. I thought it was a no brainer tbh, its just a switch with a thermocouple of some sort attached, but guy from Elnur didn't seem convinced or convincing

suffolkspark · Apr 23, 2022

Alan-N said:
Got called to look at a Gabarron CMX15 that was dead, discovered the Safety Limiter device on the CH side had tripped, reset it and bled the radiators are recharged to 1.5bar per the manual. long story short it has tripped a couple of times since. Done it today while I was there after only being powered up for 5 minutes, the water was stone cold and the Sr value was 18 (from the diagnostic routine) , it also this time refused to reset even with the mains power off. In my mind the device itself is faulty. I did call Elnur UK but the bloke didn't seem to have a clue and wanted me to send him all the details in an email, never got any reply. Am I missing any other reasons for that switch to keep tripping. I thought it was a no brainer tbh, its just a switch with a thermocouple of some sort attached, but guy from Elnur didn't seem convinced or convincing

Is it an easy and cost friendly replacement part? If it's like a clickable one like on an immersion maybe go with your gut, ive had those do this before. Explain to the customer the situation with elnurs customer service and if they're happy go for it

Alan-N · Apr 23, 2022

suffolkspark said:
Is it an easy and cost friendly replacement part? If it's like a clickable one like on an immersion maybe go with your gut, ive had those do this before. Explain to the customer the situation with elnurs customer service and if they're happy go for it

Thanks, it's a retired couple, I'll back myself and if it doesn't cure it I'll cover it. I resent the email to Spanish office where the boilers come from, might get more help from them.

UNG · Apr 23, 2022

Have you checked the pump is running and all the radiator valves are open when you reset it, other than that I would suggest a blockage in the heating circuit

Alan-N · Apr 24, 2022

UNG said:
Have you checked the pump is running and all the radiator valves are open when you reset it, other than that I would suggest a blockage in the heating circuit

Yea pump does run and radiators work fine, it stayed up for 5 hours one of the times before it tripped, then last time barely 5 minutes, but appreciate suggestion

UNG · Apr 24, 2022

Alan-N said:
Yea pump does run and radiators work fine, it stayed up for 5 hours one of the times before it tripped, then last time barely 5 minutes, but appreciate suggestion

Having found a manual eventually, the manual it does mention the flow rate needed through the boiler to maintain normal operation and the troubleshooting part of the manual does suggest checking thermostatic valves and the bypass valve, blocking of the pipework and / or pump does seem to be the main cause of the problem with these boilers
How long has this boiler been installed and did it replace another boiler if so was the pipwork and rads properly flushed at the time it was fitted, has the system got inhibitor in it and has it been checked / topped up as part of any maintainance

Alan-N · Apr 25, 2022

Thanks for that, I'll have another look at the pump side and check it is working properly, system looks less than 10 years old, if I have time I'll remove the trip switch and test it in a kettle to see when it trips, its one of those capillary tube setups.

Alan-N · Apr 27, 2022

UPDATE Elnur (UK agents for Gabarron) got back to me and asked me to turn off HW & CH and check with a clamp meter what the boiler was drawing. I was dubious but gave it a go. Boiler with nothing on was drawing just under 3KW, and I could hear water starting to boil. This they tell me is a faulty main PCB causing one of the elements to never turn off, hence it keeps working until the safety cut-out pops.

UNG · Apr 27, 2022

Alan-N said:
UPDATE Elnur (UK agents for Gabarron) got back to me and asked me to turn off HW & CH and check with a clamp meter what the boiler was drawing. I was dubious but gave it a go. Boiler with nothing on was drawing just under 3KW, and I could hear water starting to boil. This they tell me is a faulty main PCB causing one of the elements to never turn off, hence it keeps working until the safety cut-out pops.

Obviously a known and quite common fault then by the sound of that response