alpha boiler lock out - air in expansion tank??

mattE · 22 Sep 2006

Hellol

any help/ideas appreciated

i will use the 'read this first' to try and give right info

1) Boiler make / model (gas or oil) Alpha CB28 gas

2) What is / is not happening - put hot water on and boilder lights after about 10-15 secs makes shuddering noise and pressure gauge shoots up about green area then dorps and system locks out ( red light on)

3) Has ANYTHING else been done / changed recently - radiator removed about 3 weeks ago havent had heating on for 3-4 months

4) When did it (problem) start -last night for kids bathtime
5) When does it happen? eg, heating coming on or going off - HW on

6) Anything else you feel may be of relevance - alpha boilers said its air in expansion tank and to re-pressure to 0.8 - i cant find valve to use to attach pump - taken front off but not obvious

7) Please also be patient for a reply, no one gets paid to reply on these forums, and like you, our "pros" have a daytime job to do.

Any help appreciated - kids will start to smell soon

thanks Matt

kevplumb · 22 Sep 2006

pump the expansion vessel up isolate and drain the boiler first the

nick the kids bike pump (pre emptive strike)

mattE · 22 Sep 2006

cheers 4 speedy reply - kids at school so pump nicked

i cant find where to attach the pump -ive had the front off but cant see anything that looks like the pump will attach??

can you ( or any one) give me procedure for draining and then refilling boiler

cheers matt

pannierstan · 22 Sep 2006

Have you been getting hotwater O.K for 3 weeks?

Sounds to me like the pump is seized if it happens after after 15 seconds.Either that or you have no water in the system. Have you topped it up. Check pressure guage

If the expansion vessel is flat then the pressure will start to rise as the system gets hot eventually causing the blowoff pipe outside to spit out water.
Then when it all cools down the pressure will be to low and the boiler will lockout.
By the way if you are checking the expansion vessel please ensure that you open a drain point and wait until the water stops.Then connect you pump to the shrader valve on the expansion vessel, but note the drain point MUST be open when you pump up the vessel or you will get a false reading.
By the way only put about 10-15 psi in the vessel

pannierstan · 22 Sep 2006

The pressure point on the vessel is usually over the top back of the boiler so I hope you can get to it. The expansion vessel is usually a big red thing behind the boiler against the wall.

HarrogateGas · 22 Sep 2006

pannierstan said:
The pressure point on the vessel is usually over the top back of the boiler so I hope you can get to it. The expansion vessel is usually a big red thing behind the boiler against the wall.

Id call is a soft poppy red personnally. But we get the jist!

pannierstan · 22 Sep 2006

Well it could be orange like on the delightful old Chaff Celtic, or possible Grey like the Vaillant Sine 18.

Or was that tangerine and gun metal

mattE · 22 Sep 2006

what an excellent bunch of fellas - cheers

hve found the valve and will have a go tonight

appreciate it

matt

ChrisR · 22 Sep 2006

Pretty sure the Mfrs manual is oin the website - might show you where things are http://www.alpha-boilers.com/

mattE · 23 Sep 2006

found the valve its a glorious gunner red. it stands proud like arsenal. any ideas what the chelsea drain valve looks like? is there a bung i have to remove first and will dirty waste water pour out ?

cheers matt

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alpha boiler lock out - air in expansion tank??

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