Is my boiler about to explode?

[buckmoy]

Vaillant TurboMax 28 combi

When the CH is on, the pressure goes up to about 2.8 bar. When things are dormant the pressure is still above the recommended operating thresholds.

Is there an easy way to reduce this pressure a bit? Can I just bleed one of the radiators for a bit?

What happens if it gets to 3 bar? (seems to be the max dial limit).

Thanks

 

[Bahco]

Cold pressure should be 1 bar. Let some water out of a drain valve to get it down to this.
Make sure the filling valve is off.

When the heating is on you should get a small increase in pressure but if it starts ring over 2 bar then you have a problem.
Pressure vessel may need attention and you should seek a corgi engineer to rectify.

 

[corgiman]

if you reduce the pressure you will find that you will have 0 bar when the boiler is cold

check that the filling loop is not letting by (ie remove the silver hose and see if water runs) if not then your expansion vessel is see gone. check on vaillants website to see if you can chuck in an external pressure vessel ( I think you can an 8 litre one but check as i am not 100% sure) on

it wont explode the pressure relief valve will open and let the water out you will just end up repressurizing it daily

 

[meldrew's_mate]

I'm with bahco generally on this one, not saying corgiman is wrong because he is right to advise you to remove the filling loop and observe for water passing.

However it seems more sensible to remove a little fluid (by bleeding if it suits you) to reduce the pressure to a lower value. Do this with the system COLD though, final pressure depends upon the layout of you floors, and which one your boiler is on, but as said by bahco 1 bar (cold) usually satisfies 95% of cases.

 

[chrishutt]

you can chuck in an external pressure vessel

This is always an option, on any sealed system boiler. 8 litres capacity will cover most systems. Anyway it's much cheaper to do this than replace the original, especially when boiler has to be taken off wall to change it.

But before you go that far, it may only be necessary to recharge the expansion vessel - it should have a precharge pressure of I think around 0.8 bar, which you measure with a "tyre" gauge on the vessel schrader valve, while the system pressure is zero.

 

[Mike13]

You may also have some air in the system, so drop the pressure to 1.5 bar cold and then go and bleed all the rads.

Mike

 

[buckmoy]

thanks for the replies guys. The filling loop was still on a small amount. I drained using pressure relief in the end.

Ta

 

[Gasman1015]

That is not the recommended way to drain the system use a drain off.

 

[ChrisR]

QUIte - better keep checking it. If it keeps dripping, you need a new one!

 

[buckmoy]

Hey Gasman - a good tip..if only the installation plumber had thought of that when he recommended it to me! he did sound in a rush though.

I will use the lowest drain cock from now on.

WHy is it bad to use pressure relief? Out of interest.