Ongoing problems. System now needs resetting!

We had a new PCB in our Boilermate 2000 about 18 months ago. Then a few weeks ago, we started to get the hot cold fluctuation in water temperature mentioned in numerous posts on this site.

After overcoming the problem for a few weeks by use of the Immersion Heater, I changed the DHW Sensor earlier in the week and the problem seemed to be resolved.

A couple of weeks ago, the Gloworm Boiler PCB started making a heck of a racket so I changed that and again all seemed fixed.
Now, only 3 or 4 days after replacing the DHW sensor, we have had absolutely no hot water twice today! Both times I have turned off and on the mains supply to the Gledhill and the system had immediately reset itself and provided hot water straight away.

Before emptying the airing cupboard yet again this week, has anyone any idea what I should be looking at this time?

Any fault codes?
Mike
MGC/H2O
Norfolk

Mike,
No. No fault codes but the problem is now back to the dreaded fluctuation of water temperature again. However, sometimes I can fix it by resetting the the mains power and sometimes it stabilises by leaving the shower going for 4 or 5 minutes.

I can only assume it's the main PCB again as I've checked all connections, have the boiler temp set to max and have plenty of water pressure.

I do have a spare u/s pcb that burnt out a couple of years ago - presumably capacitors, so I thought about swapping the chips as they appear to be just push in. The fact that resetting the mains appears to be resolving the problem leads me to assume maybe something wrong with the programme on the board? Any thoughts?

Check the DHW pump
Mike
MGC/H2O
Norfolk

Is that the pump attached to the heat exchanger? The one on the right hand side? What can I check on it and how?

No book on the unit?
Down load one for free from Gledhill website.
Yes the right hand pump.
First check if it is free running.
Run the hot tap, see if the pump moves.
You can stop them with your finger, so normal.
Put a volt meter on the pump and see if the voltage goes up and down.
Which it should do ref keeping the temp even.
Did you change the PHE sensor?
Mike
MGC/H2O
Norfolk.

RichardG wrote:Mike,
No. No fault codes but the problem is now back to the dreaded fluctuation of water temperature again. However, sometimes I can fix it by resetting the the mains power and sometimes it stabilises by leaving the shower going for 4 or 5 minutes.

I can only assume it's the main PCB again as I've checked all connections, have the boiler temp set to max and have plenty of water pressure.

I do have a spare u/s pcb that burnt out a couple of years ago - presumably capacitors, so I thought about swapping the chips as they appear to be just push in. The fact that resetting the mains appears to be resolving the problem leads me to assume maybe something wrong with the programme on the board? Any thoughts?

Richard,
You can't just buy new big chip because it is microcontroller with firmware fused inside by Gledhill. Unless you have that firmware and programmer. The other ICs you can replace. Anyway, try capacitors, i'm sure it is the main problem on faulty board. Your current board may have the same issue with caps, being in hot enviroment they lost capacity. Electrolitic ones