Worcester 30Si misbehaving ?

[damovs]

Hello all

I wonder if anyone has any idea what might be ailing my boiler? This requires quite an explanation for afirst post, so congrats to anyone who gets to the end!

So, I have a Worcester Bosch 30 Si Compact boiler, installed just lessthan a year ago by a reputable Gas-Safe registered plumber. Though notrelevant to my current issue, I will mention that within a couple of months thepump went, and it was replaced by a Worcester engineer under their standard warranty(8 year). This was worrying, but I guess components can fail so I try toremain positive about the Worcester brand, having done a fair bit of researchbefore I had the boiler replaced last year.

At the end of last year with the weather turning cold, I felt that thatthe boiler was not heating the house (2 bed bungalow) well enough. Theboiler was functioning, the rads were warm, (I’d bled them before autumn setin), and hot water fine. However, the house didn’t warm up sufficiently,especially on cold winter days. My initial thought then was that my insulationwas insufficient, allowing heat to escape easily, so after Christmas I laiddown another 200mm layer of insulation in the loft but the problempersists. For example, if on a Sat morn the room stat is reading 15 or 16degrees, having been off overnight, even with the heating on full all day theroom did not reach 20 degrees by evening? I can turn the heating onfor 24 hours, set the room stat high (25 degrees), and it will never reach thattemp. Now am I right in thinking something is amiss?


Having looked through the boiler handbook, I see that I can set thetemperature for the heating and also for hot water, so I set the temp of waterfor the heating loop to be 70 degrees. (And let me re-state that the radsare providing heat.) But when I look at the boiler control panel itself,even when my (rf) room stat is on high, and the program set to ON, the boilerdoes not remain on continuing producing hot water for the radiators. After a while, with water temp showing low 70’s,the burner switches off (the flame symbol disappears), and then Iimmediately see the temp of water in heat loop drop, as low as mid-50’s, andjust stays like that a couple of minutes, before the boiler starts up again, theflame symbol appears, and the water tempcreeps back up again. This is cyclical,and I have only measured a few cycles, but this process is being repeated every5 mins or so. And all the time, the roomstat is set to a high temp which has not been reached, so should be demandingheat.

So, my question is, is that normal behaviour, because I think that it isthe reason I seem to be unable to heat up my house sufficiently. I don’t know if there is an ‘average time’ toraise the house temp by one degree C, and I’m sure this varies depending onhouse size, but I have had boiler on for 12+ hours and not failed to achieved atemp increase of 5 degrees. That justdoesn’t seem right to me.

Apologies for the long explanation, but hopefully it conveys all theinfo reqd for one of more of the experts here to provide an opinion, which Ilook forward to reading.

Thanks and regards
Damian

 

[ShaunCorbs]

Did you have new rads when the boiler was installed ? If not was the system flushed and a mag filter installed ?

Also no not normal

 

[ShaunCorbs]

Did you have new rads when the boiler was installed ? If not was the system flushed and a mag filter installed ?

Also no not normal

 

[Last Plumber]

Have you got a one pipe system ?

It sounds like it but obviously I haven't seen it.

If it is, and it's a slow one then the water can move around the circuit and back to the boiler before the rads get chance to warm ( because they work by gravity ).

I may of course be wrong, i'm just thinking out loud !

do you find that the rads warm in sequence or all at the same time and evenly ?

 

[damovs]

Thanks for the prompt replies.

In answer to ShaunCorbs, no the rads were already in place, but there was a power flush as part of new boiler install, and there is a mag filter in place. All the pipework is microbore, if that is relevant.

In response to Last Plumber, I did not know what a one pipe system was until 10 mins ago (good on Google!), and now I would say I have a two pipe system. There are two separate microbore pipes for each rad, and I believe that all rads get warm at the same time. I certainly haven't noticed some being hotter than others. 6 rads in total.

The reason I think that something is wrong is that even with my previous old boiler, I didn't experience this problem before. But of course I am not a heating engineer, so I have no real idea what the problem may be, if in fact it is one.

I do have a Worcester engineer coming out at the end of the week, after a 2+ week wait, but I just wanted to see if there were any opinions I could share with him if he turns round and says all is well.

Thanks again.

 

[king of pipes]

30 kw for 5 rads is alot do you have a combi ? post a picture of the boiler and pipework please may help diagnose your problem cheers k.

 

[damovs]

For anyone interested, the chap from Worcester popped round yest to check the boiler, and his prognosis is that there is nothing wrong with the boiler itself, my problem is one of poor circulation via the microbore. The boiler was off for a couple of hours before his arrival, so everything was cold. Within a few (5 tops) mins of switching it on, the heating loop temp had reached target temp of 70, both the flow and return pipes at the boiler were piping hot, but the rads still lukewarm. He got into the loft to have a look at the bypass setup, and said that probably due to blockages / restrictions in the pipework, the water was finding it easier to use the bypass to go directly from the flow to the return pipe. He suggested a re-flush may help, (it was power flushed as part of installation 11 months ago), or failing that change pipework as microbore is sh*t ! (He also said that a proper 'power flush' is not possible with microbore, and sometimes does more harm than good.)

Anyway, just thought I'd update you on status. The microbore/rads have been in place for 15 years, so perhaps they are past their shelf life? I don't know if there is a time beyond which microbore gets too clogged up. If so then no fault of original installer I guess, though hopefully he will be returning soon to see if he can address the issue.

 

[damovs]

For anyone interested, the chap from Worcester popped round yest to check the boiler, and his prognosis is that there is nothing wrong with the boiler itself, my problem is one of poor circulation via the microbore. The boiler was off for a couple of hours before his arrival, so everything was cold. Within a few (5 tops) mins of switching it on, the heating loop temp had reached target temp of 70, both the flow and return pipes at the boiler were piping hot, but the rads still lukewarm. He got into the loft to have a look at the bypass setup, and said that probably due to blockages / restrictions in the pipework, the water was finding it easier to use the bypass to go directly from the flow to the return pipe. He suggested a re-flush may help, (it was power flushed as part of installation 11 months ago), or failing that change pipework as microbore is sh*t ! (He also said that a proper 'power flush' is not possible with microbore, and sometimes does more harm than good.)

Anyway, just thought I'd update you on status. The microbore/rads have been in place for 15 years, so perhaps they are past their shelf life? I don't know if there is a time beyond which microbore gets too clogged up. If so then no fault of original installer I guess, though hopefully he will be returning soon to see if he can address the issue.

 

[Last Plumber]

Thanks for coming back.

All to often people start threads and once they have their answer, swan off into the sunset leaving us wondering !

 

[Last Plumber]

Thanks for coming back.

All to often people start threads and once they have their answer, swan off into the sunset leaving us wondering !

 

[ShaunCorbs]

If I was you I would get a price for a repipe and change from 10mm to 15mm drops if you can

 

[king of pipes]

30kw output for a 5 rad system say 2kw each max making 10 kw your way over bud , I can only think you must have a combi I would get your engineer back put some sentinel x 400 in the system and let it run for a week then drain down and flush out, take the rads off and flush em through outside replace the rads and if the rad valves were not changed a year ago change em sentinel x 100 inhibitor infill up got to be worth a go before re piping a picture would help boiler and bypass set up regards k

 

[ShaunCorbs]

30kw output for a 5 rad system say 2kw each max making 10 kw your way over bud , I can only think you must have a combi I would get your engineer back put some sentinel x 400 in the system and let it run for a week then drain down and flush out, take the rads off and flush em through outside replace the rads and if the rad valves were not changed a year ago change em sentinel x 100 inhibitor infill up got to be worth a go before re piping a picture would help boiler and bypass set up regards k

You can set a max kw for heating mate so no worries there

 

[king of pipes]

Yes bud but has it been down rated ? matey still not said if it's a combi I had a similar problem couple of years ago 24kw valliant eco tec plus system boiler down rated to 15 kw job done .

 

[jtsplumbing]

10 mm not the best to power flush, would try adding Fernox F5 heavy duty cleaner and consider replacing all radiator valves

 

[damovs]

Thanks for the updates again.

Sorry, forgot to reply to you question kop, it is a combi boiler, and I don't know if it has been down rated or not. I didn't know having an over powered boiler was a problem. I am hoping for the original installer to get in touch soon, so should I mention that to him? (I am also including some pics as requested. The bypass is in the loft, would a pic of that be helpful?)

It sounds like I should try the cleaners you suggested first, as a re-pipe would be a really disruptive exercise, especially I have recently been redecorating. It would cause a hell of a mess to replace with 15mm pipe, not to say expensive I imagine, but if that is what is required then possibly I have no choice. It's a shame that wasn't suggested at the time, as I had to have new pipe work installed in loft and to/from boiler, as a new larger pipe had to run from the gas meter to the boiler. Anyway, it is was it is for now I guess, I'll see what the guy says when he comes to look at it.

Oh yes, and the rad valves are the same ones originally in place when I arrived. So there is a benefit in fitting new valves by the sounds of things. That sounds a much les painfull path than a re-pipe.

But many thanks for all your opinions and advice, much appreciated.

 

[ShaunCorbs]

Thanks for the updates again.

Sorry, forgot to reply to you question kop, it is a combi boiler, and I don't know if it has been down rated or not. I didn't know having an over powered boiler was a problem. I am hoping for the original installer to get in touch soon, so should I mention that to him? (I am also including some pics as requested. The bypass is in the loft, would a pic of that be helpful?)

It sounds like I should try the cleaners you suggested first, as a re-pipe would be a really disruptive exercise, especially I have recently been redecorating. It would cause a hell of a mess to replace with 15mm pipe, not to say expensive I imagine, but if that is what is required then possibly I have no choice. It's a shame that wasn't suggested at the time, as I had to have new pipe work installed in loft and to/from boiler, as a new larger pipe had to run from the gas meter to the boiler. Anyway, it is was it is for now I guess, I'll see what the guy says when he comes to look at it.

Oh yes, and the rad valves are the same ones originally in place when I arrived. So there is a benefit in fitting new valves by the sounds of things. That sounds a much les painfull path than a re-pipe.

But many thanks for all your opinions and advice, much appreciated.

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the rad valves arnt the type with two pipes going into one valve is it ?

if yes get them replaced should be much better

also with combis you need to rate them on hot water not heating so your fine there, but as we have said need to be down rated

 

[hammers4spanner]

Should of got an ideal

 

[ShaunCorbs]

Should of got an ideal

hell no 😀 but i think you know that already 😉

 

[gmartine]

As mentioned previously get an engineer to run a heavy duty cleaner in the system for a week or two and then clean each rad out individually replacing each thermostat (TRV) while the rads are off (do not opt for another power flush unless they have specific experience of doing so). That really should improve circulation or bite the bullet and replace the microbore.