Potty Suprima 120L, Loud Vibration On Fire Up

[ChrisR]

Do the bearings "go" Geoff? They could be just ratting on startup I suppose?
I notice that the Response fan has a note about preserving the balance of the impeller. That's lumpy thing too.

 

[geoff@cetltd]

Yes - we sent one out today, screeched like buggxry when it came in, also the cooling fan was fouling the plate

the old 120 fans are serious business

 

[Baxi-Remeha]

to check fan speed....
1 turn off all demand to boiler.
2 attach manometer to outlet of gv.
3 on side of pcb enclosure there is a small hole with a red switch visible, move this to the down position. fan will start.
4 you should be reading about -4mbar on manometer, if not it can be adjusted using the lower of the 2 adjuster screws also through side of enclosure
5 after 1 min the fan will ramp up, you should then be getting 17.5mbar on your manometer, if not use the top adjustment screw.

hope this helps......

 

[scatmanjohn]

It helps a lot jason.

It only seems to do it now and again.

I originally went to it about a month ago and it sounded like it was about to take off.
It was LOUD. When i say LOUD i mean LOUD

I dropped the burner out which was half covered in white crusty flakes.

The top of the heat exchanger also had a lot of the white flacky bits mainly just below the flue outlet. (vertical flue)

Removed all the debris, put it back together, quiet as a mouse.

Went back last week as it had started doing it again.

Checked the burner & heat ex, small amount of debris so cleaned off.

Put it back together and tried it, No noise.

So i then put it through its ignition sequence about 15 times.

On two occasions it vibrated like hell for about 3/4 seconds.

I'm thinking that its a combustion related issue rather than the fan vibrating.

I will check out the fan speed with the info provided.

Thanks All.

 

[Baxi-Remeha]

forgot to post, last part, when set up put switch back to original position .....up.

also a good point to remember that these may struggle with a low inlet preasure. i have had them with intermitant lock outs caused by inlet gas presure as low as 14/15mbar....


just a thought, the flue seal is ok, and not vibrating....., also flue hood gasket isnt damaged...

 

[scatmanjohn]

All the flue seals are intact and in good condition.

The low inlet pressure will be worth investigating further, although it was 19 mbar when i checked it.

However it was working correctly then.

I will try it with everything else on.

That made me think about what other appliances are installed.

Its a residential care home with two other boilers, 30 KW Combis. Lots of gas cookers.

Hmmm.

Better be checking pipe sizing as well me thinks.

 

[Baxi-Remeha]

was the vibrating when it was on low fan speed or when it ramped up???


just wondering if it could be debris inside the heat x if its doing in on high rate!!

 

[scatmanjohn]

was the vibrating when it was on low fan speed or when it ramped up???


just wondering if it could be debris inside the heat x if its doing in on high rate!!

Before i removed the debris it was as soon as it fired up on low fan speed.
I was too scared to let it go to full speed as it sounded like it wanted to part company with the wall.

After i had cleaned the debris of the burner and heat ex it would do it on low fan speed for a couple of seconds and then stop.

 

[Baxi-Remeha]

hmmmm im stumped..... could it be the cooling impeller on the fan catching somthing????

let us know what you find.....


jay

 

[scatmanjohn]

Will do.

I reckon i will find that tony was correct all along.

 

[Agile]

Jasons instructions seem to be all to do with setting the gas pressure rather than the fan speed.

I am still expecting the problem to be weak mixture for whatever reason.

Have you checked the gas pressure as recommended?

And whats the gas pressure at the boiler inlet at minimum and maximum power??? What are you using to measure gas pressures?

What is the CO2 percentage at minimum power?

Tony

 

[Baxi-Remeha]

those instructions are to set the fan speed, not the gas preasures....

the fan speeds need to be right so as the mixture will be right...

 

[ChrisR]

4 you should be reading about -4mbar on manometer, if not it can be adjusted using the lower of the 2 adjuster screws also through side of enclosure
5 after 1 min the fan will ramp up, you should then be getting 17.5mbar on your manometer

Sorry - This is with gv shut, right? so you mean minus 17.5 mbar?
Good info, thanks.

..
Now have one of these intermittently locking out. Boards, leads and gas valve have all been changed!

Supply is a bit undersized though. Would it lock out due to that on initial lighting (must be a v low gas rate at that time) or when the fan ramps up? Never does it when anyone's there of course.

 

[Agile]

Sorry not to have followed you Jason.

This PCB with the red switch is this on the fan ???

Or is it on the NEW enclosed PCB ?

Setting the fan speeds will only set the min/max power. The mixture will be determined by the gas valve characteristics and the injector etc.

Where does the Suprima 120 MK2 PCB ( 5106568 ) come into this?

Over to John for the answers to my questions above? Then we will be able to see whats wrong!

In addition, have you checked the flue seals are effective and not causing spillage from inner to outer?

Tony

 

[Baxi-Remeha]

Sorry - This is with gv shut, right? so you mean minus 17.5 mbar?
Good info, thanks.

err derrr sorry yeah, MINUS 17.5.


another thought for locking out is the regulator on the meter. is it slow to react too the sudden change in preasure in the supply pipe, cause these boilers are quite sensitive to insufficent gas preasures.

This PCB with the red switch is this on the fan

no its accesible through the side of the pcb enclosure.

Or is it on the NEW enclosed PCB ?

no its on the suprima 120 pcb (not enclosed 5111603) their is 3 hols in the enclosure behind the pcb, 2 have adjuster screws to set the fan speed, and the other is access to the switch. (up for normal, down for setting)