Boilermate 2 & Suprima 30 Hot Water Issues

I'm having problems with my hot water taps. The central heating works fine.

The system was working fine until we started to get intermitant hot water. It starts hot for about 10 secs then turns warm and finally cold.

The boiler has a flashing green light, which I believe to mean a demand for heat is detected.

I turn off all the suprima boiler and boilermate and restart. The hot water supply returns for a couple of days until the taps run cold again and the boiler green light is flashing.

I have had two plumbers come over and they didnt have a clue.

Please help its driving us mad.

Thank You

Hi Jamie,

This initially sounds like water scale or a failed blender valve. But given that re-booting the boiler seems to fix it I think you actually have a problem with the boiler circuit board. Particularly likely if you've already had it changed in yours.

The current (Siemens) control board for the Suprima has a nasty fault that shows up like this. It heats the boiler to a different temperature every time the boiler fires. I think yours might be only heating the store to, say 35 degrees C on occasions, but perhaps 60 or 70 degrees on others. Restarting the boiler makes it appear to work correctly but then it turns off at too low a temp once again giving the symptoms you desrcibe. Took me a while to diagnose the first one of these I encountered!

A new thermistor and boiler control board, both for the boiler, will almost certainly fix this but don't bank on it. Remote diagnosis can be tricky so I'd need to see this system first to advise you with any certainty.

Cheers, Mike

Thank You Mike

I actually reset the system yesterday. The boiler fired for a about 30mins and stopped leaving the red light on. Hot Water was perfect. I assume this means water temp demand satisfied.

This morning when I came down the boiler had a flashing green light only. Im guessing the boiler cuts out before the required temperature is met just like you said.

What would you recommend to try first. I always start with the cheapest option

Jamie

My current pcb is the original. It has not got the lockout problem. The green light just keeps flashing and then igniting. The red light is hardly ever on.

The boiler thermister is the most likely culprit then. The original board does not cause the problem I described, only the Siemens version introduced about five years ago.

Make sure you have the thermister installed by a suitably-qualified gas technician.

Cheers, Mike

Mike sorry to be a pain.
I had no hot water again this evening.
I just switched the heating thermistate to max.
The boiler stayed on for ages and stopped leaving just the red light on
And now there is plenty of hot water.

Sounds to me as though the store was cool when you got home, and turning the CH on prompted the boiler to start. You are going to have to buy yourself an electrical test screwdriver or multimeter to diagnose this properly :-)

Next time you have no hot water you need to not touch or change or adjust anything, but immediately test to see if there is a 'call for heat' voltage (230Vac) present on the SwL terminal on the boiler. If there is, then feel the pipes at the top of the boiler to see if they are hot (REALLYhot!) or just warm/cold and report the results back here.

Cheers, Mike

Mike

There is a call for heat and the light is flashing green.
The pipes are red hot above the boiler.
I'm thinking its the pump not moving the water away from the boiler.

Jamie

I take it you mean the boiler pipes are hot whilst you have the 'no hot water' problem?

In which case yes I agree - the boiler pump on the Boilermate is not pumping the hot water away from the boiler, so we need to find out why not. Is the pump spinning? Find out by removing the big silver screw in the centre. This exposes the motor shaft and you can see if it is spinning fast. If it isn't spinnign then test for electricity feeding the pump. If none whilst the green Boilermate light is ON then you have a knackered pump overrun board. IF it IS spinning but no water is being pumped, then you probably have hardly any water in the store and it needs filling up.

Cheers, Mike

MIke

The pump is running but I would'nt say fast. The pump is set to the middle setting. I have now set the the pump to max.
Hopefully this will help.
Thanks Jamie

Mike

The boiler has been working fine and Hot water is RedHot. I think we have found the problem.
Do you think it is just a matter of time before the pump fails completley. The system is 11 years old now.

Thank You for your help.

Jamie