Worcester Greenstar 30CDI-pressure issue

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Longshanks

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Apologies for this. Know the answer is out there somewhere but er indoors is giving me GBH of the ear and imposes very demanding standards!!
This is going to seem like 2 questions for the price of one but they are inextricably related:

1. Have Worcester Greenstar 30CDI condenser boiler and the pressure gauge has gradually crept into the red zone (hovering around 3). I have the pressure relief key but can’t locate the connector under the boiler. Can you advise me on the location and what target pressure should I be aiming for?

2. The towel rail (fitted about 3 months ago with our new bathroom) does not warm up properly. It’s a small one-about 3 foot high but the top rungs don’t heat up. I know I need to bleed it like I would with a radiator but I’m not sure if this is risk free as the system is now sealed.

Many thanks

Longshanks
 
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First, bleed your towel rail radiator. This will have the effect of reducing your boiler pressure and hopefully getting it to work.
Then, reduce the boiler pressure by bleeding off at a convenient rad - its the most boiler friendly way. Keep this up until you are about 1 to 1.5 bar.
If the pressure increases after that - and keeps climbing - suspect either the filling loop isn't fully shut off or posibly a heat exchanger issue.
Expect the pressure to rise a bit when the CH is on, but the pressure shouldn't bounce about.
John :)
 
Many thanks.

When you say "bleed at a convenient rad"

Do you literally mean any rad.

Do I have to switch the boiler orrf before bleeding?

The boiler is only about 8 months old. Would you expect either of the problems you cite to occur within this period?

Many thanks

L
 
Hi - just bleed water off from any radiator that is convenient to you. This will lower the pressure in your entire system. Be patient - it can take a while. The boiler is probably best off when you do this.
On such a young boiler, I wouldn't expect any problems regarding heat exchangers. More than likely, the filling loop is slightly open - even one drip every minute can overpressurise the system after a while.
There's an article in the FAQ section regarding the filling loops on these.
John :)
 
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Hi again

Forgot to add:

Is there a reason for relieving the pressure at the radiator rather than the boiler itself?

Would you recommend turning the boiler off for both bleeds? I.e the towel rail and the nominated one to reduce the pressure

Am I likely to face probs when firing the boiler back up?

Many thanks for your time.

L
 
Many thanks

Checked the FAQ's but they don't address the specific points:

1. Relieving pressure at rad versus boiler

2. Rationale for turning boiler off

3. Potential probs refiring boiler

Many thanks
 
You can indeed release pressure from your boiler by opening the pressure release valve (PRV) which has a knob on top which you turn a little...the trouble is, these things are notorious for not sealing up again once shut, usually ending in their replacement.
With the boiler off, there's still plenty of pressure in the system, which allows you to drain down to a specific pressure more accurately.
So long as you repressurise the system before attempting restart, all should be well. Modern boilers lock out if the pressure is low so I guess its best avoided not doing so.
As recommended, its also a good idea to check the air charge in the expansion vessel when the system is depressurised. An average figure for these is 10 psi.
John :)
 
Many thanks

I'm being really thick here but how do I re-pressurise the boiler before switching back on?

Ta

L
 
Maybe this boiler has the plastic key filling loop fitted? Thats the one where you insert the key, lock it and then turn the valve to its right to allow water in?
There's probably a better explanation in the FAQ's.
The Worcester Bosch website has full instructions for you to download if you wish...well handy!
John :)
 
Thanks again.

Is this the same key used to relive the pressure on the boiler? (there is a white plastic key attached to the underside of the boiler cover).

Many thanks

Longshanks
 
John

Spoke too soon. Am going to do this tomorrow and have now looked at all the blurb in FAQs etc (didn't find Worcester site that helpful tho).

Just one last query if I may:

In the middle of this thread you refer to using a convenient rad to "drain down to a specific pressure more accurately" However you then refer correctly to the need to repressurise etc. When I follow this advice in relation to Worcester B in the FAQs it refers to turning the knob to get water in until you get the correct pressure etc. My only query is wouldn't the rad drain already have produced the correct pressure?

Still a tad confused but I always make things more complicated than they already are!!

Ta

Longshanks
 
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