Possible faulty boiler?

[pippo]

Hi,

I have a worcester 28i junior boiler. When it was installed in March, I can remember that when the heating was switched on I could hear the pump kick in straight away and then the heating would be hot very quickly. The heating was not used since then until recently, however now when the boiler is switched on, the pump doesnt kick in straight away like before. It does sound like it is heating up however the heating flow pipe is only slightly warm. This will continue for around 5-10 minutes and then I will hear the pump kick in and then the whole system gets hot very quickly.

This isnt really much of a problem I guess but as the boiler is still in warrenty and it is acting different from before, I thought I would find out if this is a problem I need to fix.

Thanks

Pippo

 

[Gasman28]

Is the hot water working OK?
It could be a very slow reacting diverter valve.
If it's under warranty, call the manufacturers for repair.

 

[pippo]

Hi gasman28

the hot water is working as normal, when the pressure drops from the tap the boiler kicks into full chat straight away and the hot water takes a few seconds to come through.

pippo

 

[pippo]

Ok just rechecked the boiler and my original description was incorrect, I think I am confusing the fan and the pump noise. Here is what I think is going on now:

Switch the heating on, seems to fire up ok, can hear the fan whirling, can hear it igniting and then the green "flame" light comes on and I can feel the flow pipe begin to heat. Then a few seconds later the fan slows right down until I cant hear it anymore, the green light remains on and there is a light humming noise (perhaps the pump?) and the flow pipe begins to go cold. This continues for a good few minutes and then the fan starts to build up to full chat again and i can here the flame re-ignite (green light was on all along) and then the flow starts to heat up very fast and the heating begins to work very well as it should. Is this normal?

I also didnt mention that I replaced an old microbore system with new 22mm feed and return pipes and 15mm tails. Has there been a problem with me refilling the system ? All i did was pour inhibitor down one of the pipes, reconnect it and then fill the system using the filling loop. Then i kept bleeding/filling the radiators. Is there perhaps some kind of air lock in the boiler due to my filling technique?

Thanks for any help

Pippo

 

[Joe4542]

From what your describing, it sounds like your boiler is working fine.

I know what you mean about the boiler when it 'really' decides to GO...it fires up to basically full rate and continues until flow reaches required.

I have known them to sometimes take a while longer in their 'test' state where they just run at min rate, to check if it needs to goto full, don't really know why there is this differnce in timings - must be something in the programming.

As for bleeding the boiler - these do have a tendency to collect air in the main h/e, and they have been designed with a bleed tap/hose within the boiler casing for this purpose. Although if you're not having big problems with heat output (banging/hissing/boiler rapidly heating up and then cutting out - even tho little heat output) - it may not be worth the hassle of taking the casing off.

You can see the bleed tap page 6 of your installation and servicing handbook for boiler.


Joe

 

[pippo]

Hi Joe,

I found a valve on the top at the back, which is similar to a tyre valve with a screw cap, so i pushed in the pin and expelled lots of air. This reduced the pressure in the system to 0. i topped it up to just over 1 bar and fired it up. It kicked in fully and the pipes are hotter than before, i can only touch the pipes and the top of the rads for 1 second so im happy.

I hope bleeding through that valve hasnt done any harm, but its working sweet now. I didnt do this when i filled the system after changing all the pipes a few weeks back and the system has never reached the heat its at now.

cheers

pippo

 

[mulls76]

Be careful, it sounds like you might have let all the pressure out of the expansion vessel which will probably need re-charging now. Keep an eye on your pressure gauge, you may find it will go up towards 3 bar when your heating has been on for a while.

 

[pippo]

Oops,

pressure rising to about 1.75, will keep an eye on it.

pippo

 

[pippo]

Mulls 76,

from what i have read about the ev, it would seem that i have indeed let the pressure out of it.

But now I am curious why the system is now kicking in fully and heating up quickly like it did when first installed when I switch the heating on, and can i re-charge it my self with a foot pump to whatever the pressure is for this boiler?

 

[mulls76]

Not too sure why your system seems to be working better, maybe you've shifted some air out of the heating cicuit as well. You will need to recharge the EV if you dont want any further problems, check the FAQ on this site which will tell you how to do it correctly.

Cheers

 

[Joe4542]

Hi,
yes - it was defo the expasion vessel you emptied... It WILL need to be recharged, else the system water has no real expansion ability (other than any remaining air in system) and so will expel system water out through the PRV.

As Mulls76 says there may have been some air trapped that was dislodged when you emptied the expansion vessel and re-filled it.

Joe

 

[dfaz]

firstly you have deffinately emptied the expansion vessel and it will need recharging secondly if you read the instructions the boiler needs the fan to run at high speed for the the boiler to ignite correctly once the flame has been established and indeed the green light comes on the boiler looks for a differential temperature rise so it can etablish what gas rate to put into the heating this helps the boiler stay in the condensing mode longer so is more efficient and also helps to stop expansion noises through your house it sound like innitially there wasnt a fault just a missunderstanding of how the boiler opperates hope this helps
Dave

 

[lifesagasman]

did you notice the dates on these posts???

 

[dfaz]

DUHHH!