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Plumberpro
Plumberpro, Plumber
Category: Plumbing
Satisfied Customers: 634
Experience:  Heating and plumbing answers. 20 years experience
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What should the correct pressure be in the expansion vessel

Resolved Question:

What should the correct pressure be in the expansion vessel of a Biasi Prisma 24SE combi boiler please?
If it is too low, will it prevent the fan from starting?
My problem is that the fan is not starting.
Submitted: 2 years ago.
Category: Plumbing
Expert:  Plumberpro replied 2 years ago.
Plumberpro :

Hi , 1.5 bar

Plumberpro :

It won't prevent the boiler from firing , only birth before a sure is below 1 bar

Customer:

What does "birth before a sure" mean please?

Customer:

Hello, is anybody out there?

Customer:

Don't you think it's worth checking on the answer you gave? Perhaps your customer might have a query? A query such as asking to type in English? Or maybe how to claim a refund?

Plumberpro :

Sorry , my tablet does this predictive text thing .meant make sure the pressure gauge reads above 1 bar

Plumberpro :

The fane will not start unless the pressure is right

Plumberpro :

The fan will not start unless the pressure us right

Plumberpro :

The fan will not start unless the pressure is right

Plumberpro :

Just doing my lines, practice makes perfect.

Customer:

Well the pressure is right. It's 1.5 bar, so why won't the fan start? I believe the sequence is fan, pump, ignition. Is that right? If the fan doesn't start, then nothing else will start, so what's preventing the fan from starting? If I put 230V on the fan from the mains, then it works, so it's not the fan.

Plumberpro :

Just double checking the manual. 5 mins , thanks

Plumberpro :

It is pump running , flow switch operates, fan runs , air pressure switch operates, boiler gas valve opens on low , sparking begins, flame rectification probe( sensor) detects flame , gas valve opens fully . temp sensors regulate

Plumberpro :

So you may have a problem with your pump or flow switch

Customer:

So the order is 1st Pump then 2nd Flow switch then 3rd Fan then 4th Air pressure switch then 5th Gas valve then 6th Spark.

Customer:

I'll have to check my pump tomorrow. Thanks

Plumberpro :

Your welcome

Plumberpro :

Hi , could you please rate your answer , thanks

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