Vaillant ashp (my battle with).

[Gone West]

Hi @zoothorn. I wouldn't worry about noise from the buffer tank. Ask yourself if your hot water tank makes any noise, ours doesn't. The buffer tank just holds a volume of water and doesn't have to be 1m x 0.5m. It's the volume that's important so could be taller and slimmer and fit where the hydraulic unit is housed.

[HughF]

55 minutes ago, Gone West said:

Hi @zoothorn. I wouldn't worry about noise from the buffer tank. Ask yourself if your hot water tank makes any noise, ours doesn't. The buffer tank just holds a volume of water and doesn't have to be 1m x 0.5m. It's the volume that's important so could be taller and slimmer and fit where the hydraulic unit is housed.

There’s no point in pointing this out to @zoothorn, he’ll just question if you have direct experience of a vaillant buffer tank and if not, say you’re unqualified to advise him.

 

 

[zoothorn]

5 hours ago, ProDave said:

Obviously you cannot cope with any heating system that involves water and radiators because water moving through a pipe might make a noise and nobody can guarantee it won't.

 

The company have offered to change your system for a monoblock which puts all the parts that can be expected to make a noise outside. That is the best offer you will get.  A buffer is no more likely to make a noise than water passing through a radiator.  But it seems you cannot accept that risk, you are not prepared to even let them try it.

 

So the best thing you can do is rip out the present system, sell it on ebay as almost new not very much used, and install electric storage heaters that have no moving parts and no water.  but be warned they might make the occasional clicking noise as they warm up overnight and parts expand.

Sell a system, that has been deemed faulty/ not fit for purpose/ that 8 engineers couldn't fix/ deemed to be decomissioned. Eh??

 

Plud the fact it seems fir some inexplicable reason, you think this faulty system.... wasn't faulty at all, so much so you (& everyone else) could quite happily have lived with it- that it's just me that can't!! 
 

I'm dumbfounded by this. You refuse now to believe, that my current system, is even faulty. To fit some convenient narrative that -I- am at fault, instead. Astonishing.
 

I really didn't expect you to just jump in with the sniping pack ProDave. But such is human nature, I guess you just felt compelled to join in. Gaggle/ pack/ it's so predictable.

 

Zoot
 

[ProDave]

9 minutes ago, zoothorn said:

I'm dumbfounded by this. You refuse now to believe, that my current system, is even faulty. To fit some convenient narrative that -I- am at fault, instead. Astonishing.

I don't believe it is faulty, I just believe it is not up to your exacting standard re noise, and not adequate for the high heat demand of your particular house.

[zoothorn]

1 hour ago, Gone West said:

Hi @zoothorn. I wouldn't worry about noise from the buffer tank. Ask yourself if your hot water tank makes any noise, ours doesn't. The buffer tank just holds a volume of water and doesn't have to be 1m x 0.5m. It's the volume that's important so could be taller and slimmer and fit where the hydraulic unit is housed.

Hi GW. Thanks, & I am somewhat reassured it may be ok. 
 

But it's size is still the overriding issue. The only issue.
 

I've explained why putting it (tbh I don't think a fitter has enough room anyway) in this bedroom cupboard ruins part of my house: my only storage is here: currently I squash xyz abc around & behind this wretched noisy (FAULTY) unit box. I have nowhere else for storage. A bigger tank, fills that space entirely.
 

Imust have a smaller one. If the house heat loss calcs determine the size of the system (10 kw is a known figure: sureky this is the only -figure- of any relevance anyway).. then  could I not propose this:

 

My main sittingroom is stone cold. Literally. 2 big asho rads in here do -nothing- as they cannot be expected to combat the huge cold. So they are wasted, being on.

 

If I were to say to them " I promise to not put 2 big rads on" (also I have a spare bedroom with a rad that seems daft to have on if 95% of year it's vacant).. could I not ask fir a SMALLER system. Maybe 7kw if we have reduced the rad number/ reduced the overall water volume, by switching 3 off.

 

?? Is this avenue viable do you think?? IE if the chaps here say the bigger the system the more likely a buffer needed.. then I just need to aim for a smaller system. Which will either have a smaller buffer, or, none at all.

 

Thanks Zoot

 

 

 

 

[Beelbeebub]

2 hours ago, zoothorn said:

Sorry this makes no sense to me. I've said this too: The installer has no knowledge that I have used the prior system 'wrong' (this alone is infuriating: I have no option but turn it off to sleep!!).. no knowledge other than the system is defective & to be replaced. 
 

The new installer is A) not the original installer. B ) has no knowledge of the noise complaints, history of the old system: I asked him & he was 'meh.. I'm just evaluating the new system, all I know is old was is defective & a different yet similar sized one to be fitted'. 
 

So essentially he gas come to a new house, & doing his usual job of evaluating where the units will go. Whilst talking with me, the homeowner.

 

It seems now folks are clutching at straws, scrambling for a conjectured reason why a buffer has been proposed when one is absent now. It simply now feels like everyone is siding with Vaillant/ the fitter, & siding against me. Typical of forums- a pack forms. Single out the weakest type instinctive thing. Bind together the pack.

 

I should've just asked: can anyone who definitively knows the answer, answer the question? If not, perhaps best not give a personal theory.. because it adds to stress, as I feel inclined to answer the post for being rude to ignore it.

Your misuse of the current system could very well have produced the symptoms of a system with insufficient water volume. 

 

As you haven't told the new installer what you have done,  he would have to conclude that the system has insufficient water volume. Therefore the solution would be to increase the water volume. Hence specifying a buffer.

 

You choice looks to be accept the offer or stay with your current system. 

 

Personally, I'd go with the new system. It looks, from the photo, that the buffer will fit where the hydraulic box went. Close the door and you won't know it's there. 

[zoothorn]

3 minutes ago, ProDave said:

I don't believe it is faulty, I just believe it is not up to your exacting standard re noise, and not adequate for the high heat demand of your particular house.

NO ProDave. No.

 

I took video of it, sent to engineers, they know well the noise it makes IS WRONG/ SHOULDN'T BE DOING IT. This has been determined by them. Concluded by them. It has & still does, stumped even the head UK engineer here with his best no.2.

 

Ive outlined this in #1. Don't please now on pg5 say you don't believe it's faulty when I've explained time & again VAILLANT THEMSELVES SAY IT IS.

 

For crying out loud. What is this anti-me agenda you're riding along with?! 

[Beelbeebub]

3 minutes ago, zoothorn said:

Hi GW. Thanks, & I am somewhat reassured it may be ok. 
 

But it's size is still the overriding issue. The only issue.
 

I've explained why putting it (tbh I don't think a fitter has enough room anyway) in this bedroom cupboard ruins part of my house: my only storage is here: currently I squash xyz abc around & behind this wretched noisy (FAULTY) unit box. I have nowhere else for storage. A bigger tank, fills that space entirely.
 

Imust have a smaller one. If the house heat loss calcs determine the size of the system (10 kw is a known figure: sureky this is the only -figure- of any relevance anyway).. then  could I not propose this:

 

My main sittingroom is stone cold. Literally. 2 big asho rads in here do -nothing- as they cannot be expected to combat the huge cold. So they are wasted, being on.

 

If I were to say to them " I promise to not put 2 big rads on" (also I have a spare bedroom with a rad that seems daft to have on if 95% of year it's vacant).. could I not ask fir a SMALLER system. Maybe 7kw if we have reduced the rad number/ reduced the overall water volume, by switching 3 off.

 

?? Is this avenue viable do you think?? IE if the chaps here say the bigger the system the more likely a buffer needed.. then I just need to aim for a smaller system. Which will either have a smaller buffer, or, none at all.

 

Thanks Zoot

 

 

 

 

You could ask for a lower powered system with a backup heater for the coldest days. That will have a lower system volume requirement. 

 

I'm not sure if the MCS scheme allows such a setup. 

 

To be honest, it sounds as if your current system has been badly setup and/or run. 

 

If your house is so small the cupboard is vital space, I struggle to see how the HP cannot heat it unless it is been badly driven. Eg turned off a lot, run with too little volume etc. 

 

I look after a fairly large (2/3bed) stone cottage with crap windows, no insulation etc. Takes 8kw to heat. To be fair the tenant did have trouble heating the lounge because the rads never got hot. I traced the problem to a hall radiator that was setup with a bypass that somebody had fiddled with. It was bypassing most of the glow straight back to the boiler.  Fixed that, all the rads get toasty. 

[AliG]

14 minutes ago, zoothorn said:

My main sittingroom is stone cold. Literally. 2 big asho rads in here do -nothing- as they cannot be expected to combat the huge cold. So they are wasted, being on.

Even if they are not producing enough heat to get the room up to temperature, they will still be producing heat and as an ASHP is a cheapish way of producing heat I would recommend using them augmented by other means.

 

The 150l requirement is total volume of liquid in the system, so this should include water in your radiators, if you exclude them the buffer will have to be even larger.

 

The reason for this is that the system runs the warm water from the system back through the ASHP to prevent it freezing. The alternative is a backup heater, it is not clear why they do not plan to use this, ask the installer if you can.

 

If you have turned all of the radiators off and there is no buffer tank at the moment then you may not even have the 45 litre minimum water in the system which may be causing issues. Also as the system is undersized for your house I am not sure if running it in reverse sometimes is a good idea at all.

 

[zoothorn]

I'll await AliG's response (or anyone else's) to my idea of promising to turn off/ not use 3 rads. 

 

Failing that it seems I'll just have to continue my own begging agenda to try getting them to reduce the size of this damn thing, or consider the only additional siting idea that's been suggested.. building some exterior housing for it. 

 

Thanks. Zoot

[Gone West]

17 minutes ago, zoothorn said:

?? Is this avenue viable do you think?? IE if the chaps here say the bigger the system the more likely a buffer needed.. then I just need to aim for a smaller system.

I wouldn't have thought so. I would come at it from the opposite direction. If they say you need, let's say a 10kW heater then you need that size to heat your house, but you could increase the volume of the system by putting in more radiators and not require a buffer tank. I'm no expert on ASHP heating systems so that may not be feasible, but I would ask them.

[AliG]

6 minutes ago, zoothorn said:

I'll await AliG's response (or anyone else's) to my idea of promising to turn off/ not use 3 rads. 

Looks like we crossposted. The 150l requirement is total water in the system between radiators and the buffer tank. I suspect they are looking at a 90l buffer tank which would be roughly the size you have quoted.

 

If you turn off the radiators then there will be even less water in the system and they will want a bigger buffer tank again. If historically you have turned off the radiators then this may have caused a problem as they assume the volume of water in the radiators when making their calcs for the system.

 

I think the system will run better with the radiators on and they will be providing some heat at a reasonable cost even if you then have to run a fire/stove or whatever on top of this.

[zoothorn]

@AliG thanks so much for thst.

 

Im still struggling to under the purpose of the buffer. Even resding your post above, 3x.

 

So I still can't comprehend the reasoning for one in the proposed system, & conversely the reasoning not to have one currently.

 

I would if the 10kw figure was different. But it's the same.

 

I don't think I have the engineering mental capacity to decipher explanations (I can only do engineering basic logic). Tbh I just don't think I -should be expected to as a customer- either.

[zoothorn]

29 minutes ago, Gone West said:

I wouldn't have thought so. I would come at it from the opposite direction. If they say you need, let's say a 10kW heater then you need that size to heat your house, but you could increase the volume of the system by putting in more radiators and not require a buffer tank. I'm no expert on ASHP heating systems so that may not be feasible, but I would ask them.

Understood, I think.
 

Actually I just had the call by my nice woman in head office, right now. Urgh. Bang in the middle of the thread. I proposed the idea of a smaller system & promising to turn off my main room rads in compensation. She is putting this idea to the Renewables dept: obviously only validated if it has a smaller buffer. 
 

ALSO she briefly skipped over the idea of a BOILER option instead. S S sorry what did you say just then? I asked. Well, she dipped ino the idea of a conventional system, as a replacement instead (I think assuming this had been out to me as an option -it has never been- once they'd relented & agreed NOT FIT/ TO BE REPLACED FOC last August.
 

Well well. A boiler/ conventional CH system possible option??Another avenue to explore?? She is also putting this idea across to the Renewables dept.

 

So 2 new avenues to explore. I with a smaller buffer tank, but t'other... *no damn buffer at all, *nor any indoor hydraulic unit. Please tell me at least this * * is so chaps.

 

 Thanks Zoot 

[ProDave]

8 minutes ago, zoothorn said:

Well well. A boiler/ conventional CH system possible option??Another avenue to explore?? She is also putting this idea across to the Renewables dept.

What fuels do you have available?  I am guessing you don't have mains gas, so it would be LPG or oil.  Both need outside fuel storage.

[zoothorn]

1 hour ago, ProDave said:

What fuels do you have available?  I am guessing you don't have mains gas, so it would be LPG or oil.  Both need outside fuel storage.

Urgh good point. No mains gas, no.

 

Damn I thought that was my ticket out.

[AliG]

2 hours ago, zoothorn said:

Im still struggling to under the purpose of the buffer. Even resding your post above, 3x.

 

I'll try to explain this simply. I am not 100% sure myself but this excerpt comes from the split system manual. It would be the same for a split or mono system.

 

1. You need a buffer as UFH and radiators will run at different times and the ASHP is not efficient running in short bursts (short cycling). With a buffer tank the ASHP heats up the water in the tank as well as in the heating system and when the heating system calls for heat this heat can be supplied first from the buffer tank before the ASHP runs for a longer burst again to heat up the tank and water in the radiators/UFH loops.

 

2. When you run an ASHP, it is like a fridge running backwards. If you stand in front of it, the air coming out is cold as it has drawn the energy out of the air and used it to heat water. In the winter, when the ASHP runs harder, eventually this causes water vapour in the air or rain/snow to freeze onto the coils of the ASHP which stops it running efficiently. So every so often it will run a defrost cycle to melt the ice. Indeed you will see a large amount of water running off it in winter. There are two ways to perform this defrost cycle, you can either run a backup heater directly in the ASHP, or you can briefly reverse the system and use warm water in the system to melt the ice. This is why if you have no back-up heater you need a buffer tank as you need a large enough amount of warm water so it carries enough energy to melt the ice ("sufficient thermal energy" as it says in the manual). It is also why turning off the radiators is a bad idea as it could impede this function by reducing the amount of warm water available to the system.

 

I can only assume that the current split unit has a back-up heater and the mono unit is not planned to have one. You would have to ask the installer the reason for this. Both units appear to be able to have a back-up heater and have the same requirements for 45l of water with the heater and 150l without it. Unless of course the current unit was incorrectly installed with neither the heater nor buffer. Someone should be able to tell you why this change has happened.

 

Just to be clear the 45l and 150l figures are for the amount of hot water in the whole system. Radiators tend to hold less water than UFH loops, so your system probably does not have much water in it and would need a larger buffer tank than someone with UFH needs. This issue why altering the number of radiators would alter the size of the buffer tank.

[Beelbeebub]

It's the thermal mass of the system. 

 

UFH systems have greater thermal.mass than radiators, especially the cast in slab systems. The heated slab in my house is equivalent to about 6,000 liters of water. 

 

This means the pump doesn't have to shirt cycle and when it needs to pull heat from the system to defrost it won't overcool the system. 

 

That's why the systems with heaters can have a lower volume. The heater can kick in to provide the energy for defrost if needed. 

 

ZT might be able to get away with the Grant internal buffer. It's 30l and has a heater built in. So the rest of the system only need to be 20l.

[zoothorn]

I don't have UFH though. @AliG you are very kind to try explaining all this. To redact it & think how I could understand it. But I just don't, barely a word of any of it. Even the 'fridge running backwards' which is the pg1 analogy give to me outside my home to explain in very basic terms how an ashp works.. is, 3 years later, incomprehensible to me. I try & try to imagine what this simplest idea could be. Backwards? Backwards? No idea on gods earth what even this could mean. 
 

Like my mum driving her car analogy, I don't think I -need- to know, how an ashp works.. let alone what on earth this tank is for. Let alone why one system has it & it's replacement doesn't. I just need help with how I tackle Vaillant to either: reduce its size, or d without it. If this means needing engineering degrees.. then Im fkd.

 

I do like to know how something works though, especially if I have to live with the bloody thing seemingly waling up, doing things, when it wants. I hate not knowing -why- it's just come on for 5 minutes at random the during the day. It took me 2 winters of insanity to find the reason why it does the overnight thing ( which at the very least, I WILL have resigned to being outside & away from my bedroom: although this doesn't mean as a certainty that I won't still hear it: the design if this ting is so bad I have no confidence even it being outside).

 

Very frustrating to hear the thing even now, suddenly go on for 5 minutes. Why. Why has it just done that? I ask myself. I have no idea. Drives me a bit bonkers, just this (daytime, not that loud, but just why should it be doing anything, whatsoever, at 10.55am, in August?? My god how I loathe this thing). 
 

Thanks, anyway. I think Ive exhausted myself & everyone too trying to help. Apologies. I have my last last gasp idea (my own) put to Vaillant: to turn off my main room rads, & them install a smaller 8kw ashp monoblock. Of course they'll refuse it, but 2% chance is better than 0%.

 

Zoot

[AliG]

To keep it very simple, ask them why they cannot install the backup heater in the new ASHP which means it will either need no or a very small buffer tank.

 

Ask them if the current ASHP has a back-up heater. If so why can the new one not have one?

[zoothorn]

6 hours ago, Gone West said:

Hi @zoothorn. I wouldn't worry about noise from the buffer tank. Ask yourself if your hot water tank makes any noise, ours doesn't. The buffer tank just holds a volume of water and doesn't have to be 1m x 0.5m. It's the volume that's important so could be taller and slimmer and fit where the hydraulic unit is housed.

Hi GW. Well this is one angle I hadn't thought of. Great. That being asking the if I can pay, for an entirely different mfr buffer, of the same size they insist.. & go shopping for a slimmer one. And go around here evaluating where the heck this could go. At least if slimmer, I can possibly find one spot without ruining my cottage. Cant be the cupboard as its likely not tall enough.

 

But they'll counter this saying they cannot fit other mfr's equipment, or your guarantee is shot doing so, or simply their fitter says no.

[zoothorn]

3 minutes ago, AliG said:

To keep it very simple, ask them why they cannot install the backup heater in the new ASHP which means it will either need no or a very small buffer tank.

 

Ask them if the current ASHP has a back-up heater. If so why can the new one not have one?

AliG. I've just tried, three times, to read your post here.. to make sense of it.. in order to ask what you suggest.

 

I haven't got a clue how to even understand this. If I were to read out your post, to them for example, the answer... would be incomprehensible. I could conceivably only record it on a dictaphone/ type it out in a post here. But that is getting ludicrous.

 

The backuo heater. Its like an alien being I have no conception of what it is, where it is, now, or in the future, whether inside another unit, attatched to it.. Im this stumped, just by twi words: backup heater. 
 

Its just far too complicated. To you it's simple. To me it makes my head ache trying to think what X could possibly mean, look like, be. I just can't cope, apologies. Im absolutely exhausted.

 

Zh

[AliG]

OK @zoothorn I don't want to get you frazzled. Feel free to read this tomorrow.

 

Your current and your replacement ASHP both have the same requirements for minimum water volume in the system. 

 

The requirement is 45 litres if they have a backup heater installed in the heat pump and 150 litres if they don't. You don't need to know anything else about the backup heater just that with a backup heater you need 45 litres of water in the system and without it you need 150 litres.

 

If your current ASHP does not have a buffer tank the assumption would be it has a backup heater so only needs 45 litres of water in the system and this is covered by the water in your radiators and pipework.

 

So if the new ASHP also had a backup heater it also would not need a buffer tank. The only reason it would need a buffer tank is if it does not have the heater. So ask them if it can have a backup heater instead of a buffer tank like the current one.

[SteamyTea]

51 minutes ago, zoothorn said:

 

Very frustrating to hear the thing even now, suddenly go on for 5 minutes. Why. Why has it just done that? I ask myself. I have no idea.

Are you serious?

It is because your house has cooled down.

52 minutes ago, zoothorn said:

I have my last last gasp idea (my own) put to Vaillant: to turn off my main room rads, & them install a smaller 8kw ashp monoblock.

So you are going to reduce the water volume of the system, so where is the buffer tank going to go.

You would be better off suggesting that you will put more radiators in, and never, ever, turn them off.

54 minutes ago, zoothorn said:

Like my mum driving her car analogy

So your Mother does not know what the steering wheel does, or the pedals, indicators, headlights.

No wonder the Welsh roads are the most dangerous in the country.

[zoothorn]

@AliG

 

why is there 105 litres of water discrepency, between a system that has a heater, to one that hasn't?

 

I cannot equate a huge volume of water, to a heater. The two things seem alien ti each other. But you say they're inter-dependent. 
 

I have absolutely no idea what this additional heater's design principle is. Additional? Surely if there's some water in a CH system, it is heated by a heater. What on god's earth then, is all this about an --extra-- heater, sometimes there but sometimes not ?? 
 

And how does this bizarre extra heater thing, relate to a huge fridge sized vessel to hold water?
 

It's like someone saying a car 'oh well if it has an extra combustion engine, you need to tow a trailer on the back'. I'm sorry what did you just say, I have a what & so I need a what??? Two totally unrelatable things, but somehow inherrantly dependent on each other. 
 

It doesn't compute. With these pathetic sniping posts in between trying to read your info.. I honestly cannot cope anymore. 
 

Appreciated. Zoot