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Loud banging from Worcester Bosch Greenstar 24i Junior

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GrahamM, you are right, the boiler is indeed a Greenstar 24i Junior. I can't see a way of changing the title of the post now?

When I questioned them why they didn't do a flue gas analysis, they said it wasn't required. They said that they can check the correct burning by observing the gas flame and checking around the flue for cracks/vapour! They also said that their gas analyser was away for calibration and would be back in a week - this sounds to me like they probably don't have one. I kept stating to them that all other companies carry out a flue gas analysis as a preliminary check for a service. They said that it wasn't required.

I have sent them the manufacturer's installers and service manual which indicates that the flue gas analysis should be checked and the primary heat exchanger dismantled and cleaned during an annual service.
 
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Regarding the NOx (Nitrogen Oxide) code plug - the boiler was purchased around 5/6 years ago and I don't know if Worcester Bosch Greenstar 24i Junior boilers were supplied with them then?
 
Millsy 82 said:
I was always taught that the gas rate just shows you that its using the correct amount of gas not that its burning correctly.

On these boilers I do
1.Flue analysis on high flame (case off) adjust as needed
2.Flue analysis on low flame (case off) adjust as needed
3.Gas rate
4.Flue analysis on both high and low flame case on if a seal has gone in the boiler or flue the co/co2 will start to rise. you do tend to find quite alot of problems Ive had split flues, split seals, flues not put together correctly etc.

I might just be being fussy but better to cover yourself
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Just a note when adjusting the gas valve high an low, always finish on high as adjusting the low can affect the high, not saying you don't do this, just pointing it out for others that might not
 
M.Joshi got quotes picked 1 then went with it ok probably didnt quite say the right thing when getting a price but then how many customers do ring up and say I want a full strip down service of my worcester greenstar 24i junior they just phone up and say I want a boiler service. He went for a gas safe engineer who has come out and not carried out an essential check on the boiler that is not his fault I am sure that with hindsight he would have gone with SGI and pay the extra but then hindsight is a great thing.

Alot of people look and see gas safe and automatically expect (rightly so) that the engineer is competant but I bet every engineer on here knows people that you wouldnt ever trust but they still get work. It is so hard for the customer to get quality engineers with the amount of useless people out there.

£120 for a strip down is not expensive. If I worked for myself then I probably wouldnt charge that much but wouldnt be far off.

Anyway for your hot water problem really you need to check the flow rate out of the taps and temperature and compare it to MI
 
Millsy 82 - Below is what I posted on MyBuilder - where I came across the company in question. They also seemed quite proactive in calling and keen to do the service as soon as possible hence, why I chose them! I did confirm that the service would be carried out by a Gas Safe Registered person.

Should I have worded my request differently?

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We would like someone to do a full service on our Worcester Bosch Junior 24i boiler. Note a full service is required, not just an inspection or check i.e ensure all parts are working correctly, inspect heat exchanger and replace gasket as necessary.
The hot water from the boiler is occasionally coming out extremely hot. There are no hot water controls on this boiler.
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I would take that as a full strip down service I would phone them and get them back to finish the job and do it properly with flue analysis.
 
So how much should I roughly be looking to pay to have a strip-down service and rectify the hot water problem in the NW London area?

Is the NOx code plug expensive to retrofit on this boiler?

Also, how much should I be paying to have a couple of TRVs replaced too?

Thanks.
 
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the hot water temperature is pre-set on these boilers, can get really hot i would suggest fitting a TMV to get around the issue, or having thermostatic mixer taps fitted.

one of the reasons i dont like worcester juniors, i like to be able to control the hot water temp on my boilers 🙂
 
The maximum temperature they should get to is 55 put a thermometer under it and check that. It might be that your plate is starting to scale up and slowing the flow rate down meaning it has more time to heat up the water
 
55 is still too hot if you ask me, that's why i prefer to have hot water control on boilers
 
According to Worcester Bosch technical, the low NOx code plug can only be used on the newer software pcb. So, it seems we won't be able to have it fitted on our boiler!
 
Millsy 82 said:
The maximum temperature they should get to is 55 put a thermometer under it and check that. It might be that your plate is starting to scale up and slowing the flow rate down meaning it has more time to heat up the water
Click to expand...

I agree with Millsy your plate sounds like its scaling up giving you a slower flow rate and causing you to get scalding water. Another thing, if you have had your water main stop valve shut off recently and haven't opened it up fully again causing a slower flow rate through the boiler gives u scalding water. Have seen it be simple like this before, hope this helps.
 
Is this simply a matter of running de-scaling chemicals for a few days through the system or is a more complex de-scaling procedure required?

I don't think the cold water stop valve has been touched recently. The cold water pressure seems to be fine. Just slightly restricted hot water pressure, a little cloudy and extremely hot.
 
Your plate heat has 2 sides the mains water side and the heating side if it is scaled up then its the mains side of it so running descaler through your heating system wont do anything you can remove the plate and pour descaler in the mains side but i'd recommend replacing the plate. What you really need to know is the flow rate that you have coming out of the taps as by eye you wouldnt notice the difference between 11 and 9 litres per minute.
 
Can I measure the flow rate easily without one of those special cup meters?
 
Run the tap until it gets hot, then fill a bucket from your hot tap for 60 seconds, then decant the bucket into a measuring jug eg 1 litre at a time and this will provide your flow rate.
 
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