Boilermate 2000 No Hot Water

Hello,

I have read many threads relating to similar issues to mine and have checked / tried a lot of the tips, however still am having issues with the switching of the Hot Water Pump. Any help / suggestions would be very much appreciated.

Overview of work carried out on system since acquiring the property in Mar'16.

Mar'16 - Feb'17 System worked fine apart from quite a bit of noise evident while boiler pump in operation. Suffer from two cold radiators in the circuit one upstairs one down, lets park that problem for now!

Feb'17 Heating and Hot Water failed, nothing working, boiler not firing, first obvious problem was the header tank was almost empty, seized ball cock valve, replaced this and filled tank. Called out local plumber acclaimed to be knowledgeable about the system, he told me that the PCB (Control Board) had failed, they were no longer available and the system would need to be replaced. £3,000 quote arrived, tried another plumber (friend of the family) but unavailable at the time and has since stated he steers clear of these systems! Researched online and discover the PCB was available, ordered and replaced it myself - All good, system operating well from Feb-Dec'17 (apart from two cold radiators, park for now).

Synopsis of current problem...

Dec'17 Hot water failed on Tuesday morning, some hot water to shave but no way I was showering in that!! Removed the Boilermate cover and discovered some water leakage from Isolation Ball Valve immediately above the HW Pump, Pump all furred up and seized, electrics also failed, blew 3 amp fuse in isolator. Sourced compatible pump that day, with some difficulty removing the old one I managed to replace the pump, the offending ball valve re-seated itself after being closed, opened valves, no leaks, replaced the fuse, fired up - All good, lots of hot water, heating working normally - Had a lovely warm shower. Job Done.?

Wednesday morning, no hot water, tested the temperature sensors and obtained the following readings... Store 76, PHE 26 & DHW 8, running the "hot" water DHW continues to drop. Pump doesn't kick in, confirmed that no power is switching to the pump either at the pump or board. No Shower.

Did some more research and established that likely causes could be failed sensors, I read that these can be defective even when error codes not reported. So I ordered two GT153's but had to wait for delivery next day. Checked the header tank and also verified the bleed valve n top of the tank also bled water not air, I don't think there is an air lock.

Thursday morning, hot wired the DHW pump, perfect hot water for my shower, disconnected after shower and rewired to PCB as before. Obtained the temperature sensors and fitted first the DHW sensor since it is easiest, tested, same problem, no hot water. Tried restarting the system by using jumper 5 in the PCB, notable that the DHW pump didn't run in start up sequence, other two did. Turned off power removed jumper 5, restarted, no joy! Replaced PHE Sensor, lost a bit of water in the process since I didn't drain the tank, did get a lot of gurgling etc as system refilled afterwards. Went through start up sequence again, no joy, still no power to HW Pump when hot tap open.

Decided at this point to stop and take stock and hence ask the audience for advice. I tend to think that perhaps the PCB has failed again, but it's only been in there for ten months, could this be possible?? There are no error codes reported and it does just seem to be the HW Pump switching at fault. Anything else I have missed?

I have wired the HW pump into a temporary switch so that I can have hot water available at the flick of a switch, but I am wary that someone will leave this on at some point causing the pump to overwork and fail, any views on this????

I feel like I have exhausted all possible remedies but I have probably missed something obvious, apologies for the long message but wanted to be comprehensive.

One last point, when HW pump is running what is the maximum temperature I'd expect to achieve on the HW sensor?, with the old sensor I did get a reading on 99 which I thought must be incorrect, surely it must be less than the store temperature..?

Thanks for any help / pointers please, or is it time to fork out £3k and be done?? Adrian

It does look like the ACB has failed.
Look on here there is a guy who mends them.
Murray Martin.
PM me if you can't find it.

Also remove header tank.
Clean all the pipe work connected to it. Flush and make sure all clear and running.

Check cold feed into unit.

Check unit vent pipe

Chance are ACB failed when the water leaked onto DHW pump.

Checked fuse on ACB ?

Mike
MGC/H2O
Norfolk

Mike,

I have tried what you have suggested to no avail however I have not checked the fuse (seems obvious) but assumed that if the fuse had blown the board wouldn't function at all?  Is the fuse in that black circular holder in the top right corner on the board??

Thanks and regards, Adrian

mike wrote:It does look like the ACB has failed.
Look on here there is a guy who mends them.
Murray Martin.
PM me if you can't find it.

Also remove header tank.
Clean all the pipe work connected to it. Flush and make sure all clear and running.

Check cold feed into unit.

Check unit vent pipe

Chance are ACB failed when the water leaked onto DHW pump.

Checked fuse on ACB ?

Mike
MGC/H2O
Norfolk

Fuse is located on the ACB
Bottom left hand side.
A black round top.
You push and twist to remove.
Be careful as they can be a bit naughty.

But you are right if the ACB is lit up fuse ok.

Check all the connections to the ACB.
As they can become dodgy.
More so the top ones.

Mike
MGC/H2O
Norfolk