Opinions please on this combi install? All ok? Pics attached

[Andy.T]

Thanks guys, the system was powerflushed so should be relatively clean, there are still some old rads though (we are replacing them room by room) so there could still be a bit of crud rattling about the system.

I'll definitely look to get the magnaclean shifted then.

Cheers,

Andy

 

[DP]

ERT hot water delivery. I would collect water flowing (full flow) from hot tap over 15 seconds. Times 4 gives number of liters that that boiler will deliver (as it says in the manual) for a temperature rise of 35 degrees C (also should be stated in the manual.

Take temperature reading of cold water into boiler and hot water out of boiler. It should be 35 degrees C plus cold reading. It make absolutely NO DIFFERENCE what kind of tap you have. If you were to remove the tap and left an open ended pipe to deliver water and the cold water was at 5 degrees you should get hot water at stipulated flow rate clocking 40 degrees C. If it were any less I would be taking burner pressure readings as this area is often as ropey for satisfactory work as is flue and ventilation topic.

 

[Andy.T]

Thanks for that, i was led to believe that if the tap could draw a lot of water it could take more hot than the boiler could deliver and that the temperature would therefore drop?

Andy

 

[DP]

Boilers normally come fitted with a special washer that only allows defined flow rate. Others have valves or adjustment that should be set for prescribed flowrate. Thus when tap is fully open, water will be delivered at specified temperature rise. As suggested earlier, often poor temperature rise can be due to inadequate gas line to boiler.

 

[Andy.T]

Hiya,

I just measured DHW flow rate at the bath hot tap. It comes out at 17 litres per minute, which is greater than the 16 litres +35 degrees C quoted by the Remeha 39c. So I guess it makes sense that the temperature drops when I turn the tap all the way up.

I've not got any kind of thermometer suitable for hot water but I'll see if I can get hold of one to see if the numbers stack up to the right performance if I drop the flow rate slightly.

 

[swidders]

You don't think you're becoming a bit obsessed, do you?

 

[Andy.T]

Heh no, it's just that a couple of people have suggested that the boiler might not be getting enough gas, I thought it might be worth checking.

He's coming back to move the rad on Tueday so it'd be good to know before then if it's not performing to manufacturers spec.

It really does run quite tepid at high flow rates is all.

 

[swidders]

Heh no, it's just that a couple of people have suggested that the boiler might not be getting enough gas, I thought it might be worth checking.

He's coming back to move the rad on Tueday so it'd be good to know before then if it's not performing to manufacturers spec.

It really does run quite tepid at high flow rates is all.

I hope that it's all sorted for you soon. Spring will soon be here and it'll be nice to get out once more

 

[Andy.T]

Heh aye lol!

Except... I've got the bathroom to do refit before then.

 

[swidders]

Heh aye lol!

Except... I've got the bathroom to do refit before then.

 

[plummerman]

Hiya,

I just measured DHW flow rate at the bath hot tap. It comes out at 17 litres per minute, which is greater than the 16 litres +35 degrees C quoted by the Remeha 39c. So I guess it makes sense that the temperature drops when I turn the tap all the way up.

I've not got any kind of thermometer suitable for hot water but I'll see if I can get hold of one to see if the numbers stack up to the right performance if I drop the flow rate slightly.

Just a thought, maybe your bath tap is still fitted to a 22mm feed pipe an more water is bein drawn off than the boiler can handle? But you seem to be the man with all the technical no how. why did you get someone else in to do the job if all your goner do is try an take his work apart. He fitted you in at short notice, your pics show a fairly decent job (granted there's things that all us REAL plumbers may pick fault with, but then we do it with every piece of plumbing we see) Let it go, your rads get warm and your water is hot. Wanting a rolls royce for the price of a mini comes to mind!!

 

[Andy.T]

Say wah? Where have I claimed any technical know how? I came on here asking questions because I don't know about this stuff.

I asked some questions on the job as there were some bits I wasn't sure of. Some of those questions proved to be pretty relevant (e.g. wot no earth bond?) and have since been fixed.

It seems sensible to check that (as the hot water isn't very hot at high flow rates) that it is performing to spec?

I don't want a Rolls for the price of a Mini. I want a Mini for the price of a Mini, I'm just checking I'm not settling for a moped for the price of a Mini.

 

[Jezclayton]

Been reading this thread with interest and.....

I agree it is all too easy to criticise someone else's work but this is an open discussion now. Following on from the comments made by the installer on his second visit I just have two major issues:-

1) The condensate pipe does not comply with best practice and has every potential of freezing in which case your boiler will shut down. I challenge any RGI on this forum to come up with substantive evidence that this statement is incorrect. If in doubt, check the manufacturer's installation instructions.

2) The magnaclean requires access for servicing and should not therefore be put under a floor, let alone one covered in carpet. These devices have also been known to fail (i.e leak big time) and I pity the person looking for the source of the leak should it happen. I would sooner not fit a magnaclean than put one under the floor. Again, ask the manufacturer if you have any doubts.

3) As mentioned previously, has the Benchmark certificate been filled in? Amongst other things, this includes a section for recording hot water performance, which should highlight any problems if they exist. Get the installer to go through the Benchmark certificate with you.

Finally, the installation as a whole looks fine, but it is so often the small details that can ruin the party.

 

[Andy.T]

Thanks Jez,

On the condesate pipe thing he said that as it dropped, verticallyas soon as it left the property it wasn't an issue. I don't know if that mitigates the need for insulation/wider bore?

The magnaclean we will look to get moved to somewhere where future cleaning etc. of it is easier.

I don't think I've seen a Benchmark certificate, I've received a Corgi/Buiding Regs cert through the post but that has very few details on it. Does the Benchmark cert come later from some third party or should it have been left by the indstaller?

Thanks,

Andy

 

[David937]

On my boiler the Benchmark was on the last page of the manual.