Vaillant ashp (my battle with).

[HughF]

Tall, skinny buffer, is basically a low loss header. The grant one with the integrated backup heater is the best option, or just make one up out of fittings.

[AliG]

Much as this might work in theory, looking at the brochure it seems designed to be fitted to a Grant ASHP. It might well work with other ASHPs or there might be a different generic version that I have missed, but if it is designed for Grant ASHPs they won’t want to fit it here.
 

If you were able to use the heater in the Grant low loss header, why couldn’t you use a backup heater in the ASHP which is why I think this has to be answered before almost anything else is considered. Maybe there is something going on that none of us know about.

 

Tbh we can suggest all sorts of things but Vaillant and the installer are unlikely to want to deviate too far from their normal practices which is something we have to consider.

 

 

[DanDee]

1 hour ago, AliG said:

I don’t believe anyone makes a very tall skinny buffer. If someone finds one please post a link.

https://newarkcylinders.co.uk/products/buffer-vessels/ just send them the details of what you need.

 

 

[sharpener]

5 hours ago, AliG said:

I don’t believe anyone makes a very tall skinny buffer. If someone finds one please post a link.

 

 

As well as Newark you could try Gledhill, their slimline range is only 475mm dia cf the normal 550.

 

If Vaillant would accept a slight reduction to 90 litres it would only be 976 mm high as well.

[SteamyTea]

14 hours ago, sharpener said:

976 mm high

That is pretty precise.

 

 

[HughF]

Gledhill make a decent product, I’ve just swapped in a stainless vented into my off grid place. Nice cylinder….

[JohnMo]

1 hour ago, HughF said:

Gledhill make a decent product, I’ve just swapped in a stainless vented into my off grid place. Nice cylinder….

Not really related to this thread, but Ideal brand Gledhill cylinders to Ideal, sell them at cheaper prices to Gledhill branded ones. I bought an Ideal 210 slimline heat pump cylinder at £805 +vat, the same model Gledhill one was £987 +vat, from the same supplier.

[HughF]

1 hour ago, JohnMo said:

Not really related to this thread, but Ideal brand Gledhill cylinders to Ideal, sell them at cheaper prices to Gledhill branded ones. I bought an Ideal 210 slimline heat pump cylinder at £805 +vat, the same model Gledhill one was £987 +vat, from the same supplier.

Interesting…. Thanks for the info

[zoothorn]

Hi chaps, hugely grateful for these recent replies.

 

I've put the Q to my nice Vaillant woman, of possibly a slimmer but taller buffer (1200x300? I asked if they did one?).. or..

 

my very last gasp idea to put her way, of using a different mfr buffer. Which if this above fails, I'll ask.

 

If the installer kicks up a fuss & refuses another mfr's buffer, then Im stuffed. Back to square 1.

 

Thanks,  Zoot 

[zoothorn]

I think Ive been getting confused with my grant, & Grant too.. which I must now think, is a mfr?

 

 Thanks Zh

[Beelbeebub]

11 hours ago, zoothorn said:

I think Ive been getting confused with my grant, & Grant too.. which I must now think, is a mfr?

 

 Thanks Zh

Grant are, confusingly, a manufacturer of boilers and associated stuff. 

[zoothorn]

On 04/09/2023 at 07:15, Beelbeebub said:

Grant are, confusingly, a manufacturer of boilers and associated stuff. 

Aha! Crikey I was confused before..

 

Ok status is Im waiting for reply from my head office nice woman. Have put the different mfr buffer idea, tentatively to her. I'll mention Grant. 

 

Grateful to y'all, Zoot 

 

 

[JamesPa]

On 01/09/2023 at 22:42, ProDave said:

Some ASHP's have a backup electric heating element.  Those that do, can turn that on while it is defrosting, so some of the heat to defrost comes from that and less from the water in the heating pipes, so less water volume is needed.

That's quite an interesting feature, at least to me!  My Vaillant heat pump is whisper quiet, except when recovering from defrost, which is the only time the compressor modulation reaches anything like 100%.  In stable operation, even when its -5, it rarely gets above 60% and never above about 75% and at these levels the unit remains whisper quiet.

 

Invoking a backup heater and clamping the max compressor modulation during recovery from defrost would meant that it would be whisper quiet all the time.  SOFAIK however, Vaillant dont support this.  Do you happen to know of any manufacturer that does, it might help me put some pressure on Vaillant!

[PhilT]

2 hours ago, JamesPa said:

That's quite an interesting feature, at least to me!  My Vaillant heat pump is whisper quiet, except when recovering from defrost, which is the only time the compressor modulation reaches anything like 100%.  In stable operation, even when its -5, it rarely gets above 60% and never above about 75% and at these levels the unit remains whisper quiet.

 

Invoking a backup heater and clamping the max compressor modulation during recovery from defrost would meant that it would be whisper quiet all the time.  SOFAIK however, Vaillant dont support this.  Do you happen to know of any manufacturer that does, it might help me put some pressure on Vaillant!

what's the problem with it being a little louder than whisper quiet for relatively tiny periods of time. The compressor on mine after defrost is barely audible, and I'm sure it's no quieter than the Vaillant

[JamesPa]

47 minutes ago, PhilT said:

what's the problem with it being a little louder than whisper quiet for relatively tiny periods of time. The compressor on mine after defrost is barely audible, and I'm sure it's no quieter than the Vaillant

Nothing as far as I am concerned, but neighbour says he is very noise sensitive and objected to my planning application.  So a way to manage it would be rather helpful.

Edited Tuesday at 23:05 by JamesPa

[sharpener]

It's annoying that Vaillant's Noise Reduction Mode only supports a limit in the restricted range from 40% to 60% modulation. I don't see why they could not make it programmable to choice.

My experience with the 12kW is exactly the same, it is only noticeably noisy at the top 10% of the output range, so a limit of 90% would be ideal for a noise-sensitive location and only compromise performance at really extreme OATs.

Have you tried the Current Limit feature as an alternative? Even if it is not that effective, telling yr neighbour that it is switched on might placate him.

[JamesPa]

10 minutes ago, sharpener said:

It's annoying that Vaillant's Noise Reduction Mode only supports a limit in the restricted range from 40% to 60% modulation. I don't see why they could not make it programmable to choice.

My experience with the 12kW is exactly the same, it is only noticeably noisy at the top 10% of the output range, so a limit of 90% would be ideal for a noise-sensitive location and only compromise performance at really extreme OATs.

Have you tried the Current Limit feature as an alternative? Even if it is not that effective, telling yr neighbour that it is switched on might placate him.

Yes and it makes some difference to noise but without materially compromising performance.  However it too has a limited adjustment range and the two ranges don't overlap.  Taking NR and current limit together I can limit max compressor on my 7kW unit to between 40%-60% or between 90%-100%, but not to a value in the range 61%-89%.  Somewhere around 80% would very likely do the job in my case, but is not available.  Very annoying and somewhat inexplicable.

Edited Tuesday at 23:39 by JamesPa

[Dan F]

35 minutes ago, JamesPa said:

Yes and it makes some difference to noise but without materially compromising performance.  However it too has a limited adjustment range and the two ranges don't overlap.  Taking NR and current limit together I can limit max compressor on my 7kW unit to between 40%-60% or between 90%-100%, but not to a value in the range 61%-89%.  Somewhere around 80% would very likely do the job in my case, but is not available.  Very annoying and somewhat inexplicable.

On my system, compressor speed on defrost only seems to reach 80prm (67%).   It may go higher if needed, I'm unsure, but I haven't seen it go higher recently.   Defrost compressor speed appears to ignore any noise reduction or eco modes, so AFAIK there is no way to limit defrost compressor speed or noise.

 

44 minutes ago, JamesPa said:

I can limit max compressor on my 7kW unit to between 40%-60% or between 90%-100%, but not to a value in the range 61%-89%.

My 7kW allow for -30%, does yours not?  (I know the manual only says 40-60%).

 

[JamesPa]

7 hours ago, Dan F said:

On my system, compressor speed on defrost only seems to reach 80prm (67%).   It may go higher if needed, I'm unsure, but I haven't seen it go higher recently.   Defrost compressor speed appears to ignore any noise reduction or eco modes, so AFAIK there is no way to limit defrost compressor speed or noise.

 

My 7kW allow for -30%, does yours not?  (I know the manual only says 40-60%).

 

Well thats interesting thanks.  On my system the compressor bar diagram seems to show 80% during defrost recovery but if I go to information - live monitor it shows 99.8%, and it does definitely seem to be affected by NR mode.

 

Regarding the NR mode 'limits' I just checked mine (previously I had only read the manual) and it does, as you say, allow for -30% even though, as you also say, the manual says 40-60%.  Thanks for the tip off!

[Dan F]

41 minutes ago, JamesPa said:

Well thats interesting thanks.  On my system the compressor bar diagram seems to show 80% during defrost recovery but if I go to information - live monitor it shows 99.8%, and it does definitely seem to be affected by NR mode.

 

Regarding the NR mode 'limits' I just checked mine (previously I had only read the manual) and it does, as you say, allow for -30% even though, as you also say, the manual says 40-60%.  Thanks for the tip off!

 

As I said, mine may have stopped at 80rps because it had already drosted enough, hard to tell, but even when mine is running flat out at 100%, defrost only reaches 80rps.  I graphed this via ebusd/emon:

 

I also experimented by setting NR mode to -50% (limiting compressor to 60rps), and defrost compressor still rose to 80rps.  I'm can't say for certain that NR doesn't impact anything related to defrost, but it certainly doesn't constraint compressor to NR setting on mine.

 

 

 

 

 

 

IGNORE THIS. FORUM WON'T LET ME DELETE IT FOR SOME REASON..

 

Edited Wednesday at 09:04 by Dan F

[JamesPa]

14 minutes ago, Dan F said:

 

As I said, mine may have stopped at 80rps because it had already drosted enough, hard to tell, but even when mine is running flat out at 100%, defrost only reaches 80rps.  I graphed this via ebusd/emon:

 

I also experimented by setting NR mode to -50% (limiting compressor to 60rps), and defrost compressor still rose to 80rps.  I'm can't say for certain that NR doesn't impact anything related to defrost, but it certainly doesn't constraint compressor to NR setting on mine.

 

 

 

 

 

 

IGNORE THIS. FORUM WON'T LET ME DELETE IT FOR SOME REASON..

 

Thanks.  I don't have ebusd or another way to graph compressor modulation unfortunately.  I can graph many parameters using ha, but not this one.  So I'm reliant on the MK1 eyeball method.  I will keep monitoring.