Preesure drop

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I have a Worcester greenstar CDI 42 combi boiler.

It was just been serviced 2 weeks ago and is one year old.

I am getting a .75 bar drop in pressure between hot (88C) and cool (48C). Is this normal (acceptable) because I do not remember this happening prior to the service?

Thanks
 
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As long as it settles at the same point then it should be OK... Your expansion vessel charge may need checking though as a .75 pressure rise is a little excessive...
 
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Thanks. I had my suspicions about the expansion chamber. I got the same guy (Worcester-Bosch) back again after the service because it wasn't happening before and he claimed the boiler was A1. What, apart from the boiler can cause this discrepency?

Thanks
 
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As long as it settles at the same point then it should be OK... Your expansion vessel charge may need checking though as a .75 pressure rise is a little excessive...[


It`s a pressure drop, not a pressure rise as the system cools it will drop. :LOL: :LOL: :LOL: :LOL:
 
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Depends whether your starting point is hot or cold.


A drop from hot is contraction/cooling and is perfectly normal - as is a slight rise from cold.. A drop from cold would be a leak and not what the OP reported.
 
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and... :?:

OP is saying the pressure goes down as the boiler cools.

So, for example.

When cold the boiler is sitting at 1 bar. It heats up to 88 degrees and the pressure goes to 1.75.

As the boiler cools again the pressure returns to 1 bar.
 
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ex vessel and prv then cliver


if it was ex vessel then the boiler would show it to be over pressurised probably around 3 bar immediately :rolleyes: , if it was the prv then it would indeed be losing pressure via the blow off, easy to check innit....Basically what I am saying is: his boiler is performing exactly the way it should be and there is no problem.. ;)
 
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