Suprima 50 - New board problems?

[uk1]

I've just had the PCB replaced on my Suprima 50. It's the new style board.

With the old board, the circulating pump ran continuously until the system was shut down by the timer. When the circulating pump shut off, the system made a short sort of rattling noise and then went quiet and went to sleep until the system switched on again in the morning.

The new board seems to intermittnetly switch the pump off for a second and switches it on again. This means that we hear this rattling noise often. It's quite noisy and irritating.

My question is, is this normal for the new PCB, or does this indicate it might have been fitted incorrectly.

Any advice appreciated.

Jeff

 

[uk1]

......... cheeky I know but just nudging this back up in case someone can help!

 

[meldrew's_mate]

On the Suprima the pump should be driven by the output from the boiler, I'm assuming this is so.

I've never taken the time to see if the circuitry on the new board causes the pump to stop briefly just before the ignition cycle, but if it does you can reduce the frequency of this by correctly matching the heating load by balancing the system (search for it), and range rating the boiler output.

If the boiler is too high an output the boiler will cycle regularly, and this may have been the cause of your first PCB failure!

 

[uk1]

I'm hoping that by being more specific about my dear Optima, a kind expert on this Optima 50 might take pity on me and be able to shed light on this issue as the heating engineers seem perplexed!

Essentially what is happening is that the latest PCB has been fitted. What use to happen was that the pump circulated the water for the whoe day without stopping from the time it was scheduled to fire up in the morning until it shut down late at night.

What happens now since the new PCB was fitted, is that when the boiler shuts off when it's own thermostat cuts in, the circulating pump continues until just before the boiler starts the firing up sequence. At this point the cirulating pump then stops for a few seconds, making a noise that sounds a bit like a chain rattling in the system and then restarts once the red lights starts flashing as the boiler starts to re-fire up. This whole cycle seems to repeat every four minutes or so.

My concern is that (a) this behaviour is different from how the original PCB behaved and (b) it seems illogical. Why switch off the pump just for a second or so? (c) It's noisy switching off and on every four munites or so all day and (d) I guess it must wear the circulating pump out much more quickly.

I'd appreciate any feedback as to whether this is normal and if not what has the engineer done incorrectly to cause it and whate therefore should he look at more closely on his next visit?

Any help really appreciated as I'm desperate!

Jeff

 

[kevplumb]

I've just had the PCB replaced on my Suprima 50. It's the new style board.

I'm hoping that by being more specific about my dear Optima

why am i confused

 

[lor]

Meldrews mate , Suprima L onwards cannot be range rated, yes new board does seem to stop the pump briefly .

 

[John.B]

Why are you so desperate about this? Call the engineer back and have him check it out for you. Pump could be wired incorrectly to wrong terminal or board might have a fault.

 

[uk1]

Why are you so desperate about this? Call the engineer back and have him check it out for you. Pump could be wired incorrectly to wrong terminal or board might have a fault.

I have called the engineer back. He is back on Thursday. It's not beyond the bounds of possibility that he'll say he fitted it correctly when he hasn't - hence my question here.

Thanks.

Jeff

+++++++++++++++++++++++++++++++++++++++++++

lor wrote:
Meldrews mate , Suprima L onwards cannot be range rated, yes new board does seem to stop the pump briefly .


I guess this means it's wired correctly then!

Many thanks.

Jeff

 

[John.B]

You cannot fit a board in a wrong way as all electrical connectors have a different type of fitting. The boiler simply would not work if the board was fitted wrong. The only scope for a mistake is on rewiring the mains cable, the pump cable and the switched live cable in to the hard wiring centre.
I always mark the these cables with a pen and make a note of which wire and type of identification mark goes in to which terminal. Why dont you ring Baxi-Potterton technical help and they will tell you straight away if the pump should momentarily pause on switch over.

 

[uk1]

Many thanks that was a great suggestion.

The engineer at Baxi-Potterton said that this is normal, but also said it should have happened with the original PCB as well, which it didn't.

As this is normal he said the ratlling noise isn't normal, but couldn't say what it was other than "it might be the diverter" and "it might be the circulating pump".

The sound is like a rattling chain every time it shuts the pump - but not when it restarts. I've listened to the diverter and pump - it doesn't seem to be from here - but I can here the noise through the radiators. Any idea of what this might be would be appreciated.

Jeff

Ps. A protocol question which I'm embarrased to ask. Should I leave the whole system switched off prior to the engineers call or should I have it wamred up so he can hear it. The PCB obviously won't be too hot but obviously the pump would be.

 

[Agile]

Since there was one Suprima model with a lower power output "summer" setting, does anyone know WHY they say that it should not be range rated?

I have asked befor but never got an answer. How is the "summer" lower power setting achieved?

Tony

 

[ChrisR]

I believe L onwards means a bit more efficient (part L etc) so presumably you lose that if you alter the output. Same reason why various parts were no longer used across the range of sizes like before (though that may have changed again - see HRPC's APS's, but I digress...)

I wonder if your pcb installer altered the pump valve position for any reason. The gate type can rattle if half open. Usually they should be wide open then 1/4 turn shut, to stop them seizing.
If they're screwdriver-slot type then leave them alone!!!!

 

[uk1]

I wonder if your pcb installer altered the pump valve position for any reason. The gate type can rattle if half open. Usually they should be wide open then 1/4 turn shut, to stop them seizing.
If they're screwdriver-slot type then leave them alone!!!!

Thanks. It's always rattled. Perhaps it sounds more like a few pebbles - but it's a concistant sound. It just use to do it once a day. Now it does it 15 to 20 times an hour.

 

[ChrisR]

If the boiler was staying on longer before then it must have been getting hotter - try turning the boiler stat up!
Sounds like you need a new pump - perhaps it's now so knackered that it's hardly pumping any heat out so the boiler heats up quicker and turns off...

 

[lor]

TONY AGILE , CHRIS R IS RIGHT (AGAIN ) it is to do with efficiency and achieving sedbuk d . the suprima with the summer winter switch was an early pre part L 120 model.