Vaillant ashp (my battle with).

[zoothorn]

Hi again chaps,

 

been putting this thread off for a while, so exhausted I've been with a HUGE battle with Vaillant that I couldn't cope anymore.. let alone explaining it on BHub. But I have to wade back in. Urgh. 

 

Ok. Suffice to say my battle lasted 18 months, & came to a conclusion last August (22). Brief overview:
 

My battle was due to a noisy hydraulic unit in spare bedroom cupboard. Mechanical noise 11pm-7.30am. Intrusive even to a 3rd bedroom. Awful. 8x Vaillant engineer visits. I clocked up weeks worth of calls. They made countless unfulfilled promises to fix; after which, no-one knew what the damn noise even was. Exhaustive research by me to determine what the noise was (a starting point to me, to then explore the avenue of a fix seemed rational: although what it was doing was an impossible task for the engineers, I was determined to know what the ***k it was doing repeatedly @ 3.45 am, & why).

 

During the 18 month battle, I also had a BH thread or two. Extra workload tbh; answering posts, discussing possibilities etc, I could barely cope at this stage, all the while each night my sleep disturbed by the noise. I almost went insane at this stage.

One kindly BH member, poured thru my manual (huge bible engineer thing) & pinpointed "FROST MODE". Bingo. I'd already determined the noise innitiated at a certain outdoor temp, so putting 2+2 together = the reason. The cause. Surely. So I call Vaillant with my findings (remember 8x engineer visits & a year of calls ONLY determined it wasn't doing what it should be, not, what it was doing wrong). They replied "yes, that's what it does". FFS. I nearly lost it at this point.

 

I pressed & pressed, another round of long calls ending last August. On meds by this stage I was. Then:

 

WE AGREE IT'S NOT FIT FOR PURPOSE, TO BE DESCOMISSIONED & A REPLACEMENT SYSTEM TO BE FITTED -foc- WITH MONOBLOCK ASHP (ie unit's pump.. the specific noise-related component.. located within the monoblock outside!).

 

H A L L E L U J A H ! My battle was surely over. Hmm not quite.

 

------

 

* The new units I demanded manuals for & poured over, to remove any possibility of intrusive house noise: new fan unit & new hydraulic unit. SO FINALLY I AGREE to the swap, & thanked them hugely.

 

Installer visits (August 22), agrees where I plan new hydraulic unit to go (no way on gods earth, was I having it in a bedroom, even with promises of 'pump located outside in this system': NO FKN WAY). So I was finally-finally there!! I had it wrapped up!! Didn't I?? No. Installer throws a HUGE last minute curveball: you need a buffer, he said. A what??!!

 

No mention of this large (1000mm x 500mm) tank by Renewables dept at this * stage. Nothing. So, I had a new chapter of the battle open up. Because I simply have no room for an extra huge tank. Can it go outside?? Pleading with them I was. No, needs to go inside/ needs to be insulated they said. I was in tears at this. I couldn't cope. I gave up. 
 

------

 

A year passes, & I pick up my sword again to commence battle (no choice- another winter of overnight noise will ruin me, as well as it having ruined 3 bedrooms). I go to head office, demand the offer be renewed (they'd given me an ultimatum last August to accept the offer.. which until I knew where this wretched tank was to go, I couldn't agree to). THANKFULLY.. a kind head office woman, has agreed the offer still stands.

 

But we are at this (buffer locating) stumbling block "last hurdle" resolutely still there.

 

Zoothorn.

 

 

 

 

 

 

Edited August 27, 2023 by zoothorn

[TonyT]

I think you need to ask to see the heat loss calculations for the house to see if they have this right from the offset, then to agree on size of unit and positioning of equipment .

 

[TonyT]

Plenty ASHP’s designed without bufffer tanks if piped correctly, did you have wet central heating before and the old radiators were reused?

 

where is you hot water tank?

 

[ProDave]

+1 for questioning a buffer tank.  That is usually used in a very low heat demand house to avoid short cycling.  I would tell them to go ahead without a buffer tank and you accept the consequences that it might not run quite as efficiently, but that is unlikely in your case.

[zoothorn]

5 hours ago, TonyT said:

I think you need to ask to see the heat loss calculations for the house to see if they have this right from the offset, then to agree on size of unit and positioning of equipment .

 

Hi TT, grateful for your input/ reading my essay (it really can't be redacted down, so long this has gone on).

 

I'm at the stage you see where I just have to accept (eg whilst the iron's hot). But I do get your point entirely. Im not really in any position though I feel (nor can I cope with such engineering details tbh) to go into minutiae of heat loss calcs. They will have determined simply whatever system size is in now... to replace it.

 

The installer, their one ascociated/ linked to Vaillant, came here a year ago. He was the one who decided upon this 'buffer' being needed. Whether that was his intention to pull the rug from under me (deliberately by Vaillant) or whether it does actually need one.. how on earth can I tell.

 

Zoothorn

[zoothorn]

5 hours ago, TonyT said:

Plenty ASHP’s designed without bufffer tanks if piped correctly, did you have wet central heating before and the old radiators were reused?

 

where is you hot water tank?

 

I know this. Because infuriatingly, the one I still have in now... has no such additional buffer thing whatsoever.

 

The HWT is in this spare bedroom corner. A typical siting in houses Ive seen. 

Edited August 27, 2023 by zoothorn

[zoothorn]

4 hours ago, ProDave said:

+1 for questioning a buffer tank.  That is usually used in a very low heat demand house to avoid short cycling.  I would tell them to go ahead without a buffer tank and you accept the consequences that it might not run quite as efficiently, but that is unlikely in your case.

Hi ProDave ( thanks so much for reading my essay too). Hope all's good with you.

 

Bang on. And I've pleaded with them to not have it, but they are insistant. Why is beyond me. I've even said I'll take responsibility to not have one; this was even given to me as an 'option with possible consequences' by their Renewables dept, a year ago when their installer was ready to come to site-visit.

 

But now.. this installer is calling the tune (so far as I can gather). And he is the one insistant on his wretched buffer addition. And he tells the head office, who go with his "expert pov". 
 

Thanks, Zoot

 

 

 

 

[joe90]

Although I had a buffer in my build there are plenty here that did not and I now question whether mine was actually required? I would simply ask why this expert says the buffer is required, get it in writing and  post it here for others (who knows these things) to agree or pick it to pieces. You can tell them that “other” installers tell you it’s not required and you need to assess the situation. Once their reply is posted here we can all discuss it.

[Beelbeebub]

Can you not get the buffer stuck somewhere out of the way a garage, loft, wherever. 

 

They insist on having one, but you can indicate where it can go. 

 

Maybe if it's too much of a ball ache to fit (say loft), they will delete it?

[Marvin]

Hi @zoothorn

 

I think the understanding about the buffer tank usefulness is to do with the efficiencies achieved by the relationship between having small zoning demands and the negative effect this can have on the ASHP cycling efficiency:

 

A report that @SteamyTea has/had stated that when an ASHP reacts to a demand it takes a while before the ASHP reaches it's expected efficiency for the installation and site conditions. I think the result was that it should run for at least 10 minutes before reaching temperature to turn off. 

 

Also I feel the most efficient installation would have the shortest pipe distance between the ASHP, the Hot Water tank and the Buffer tank and the report indicated that the hot water and Buffer tank should be within the building thermal envelope.

 

If you have thermostatic radiator valves these give rise to the probability that at some stage so few would be open that the low flow of water would cause the ASHP to turn on for a short time to heat the small amount of water needing heating thereby causing the ASHP to become less efficient.

 

We have an ASHP with hot water tank and Buffer tank because we have radiators and no under floor heating.

 

Many people on Build Hub have large houses and many have underfloor heating, some with upstairs radiators as well, and these type of installations can change the need for a buffer tank.

 

Best of luck

 

Marvin.

[ProDave]

If they insist on a buffer, then can it not go where the old inside unit is?

 

On the understanding it will be SILENT and of not they WILL make it silent.

[DougMLancs]

20 minutes ago, Marvin said:

We have an ASHP with hot water tank and Buffer tank because we have radiators and no under floor heating.

 

Many people on Build Hub have large houses and many have underfloor heating, some with upstairs radiators as well, and these type of installations can change the need for a buffer tank.

We have all radiators in our 110m2 average 1960’s semi and we don’t have a buffer tank. Open loop design. 

[RobLe]

We haven’t got a buffer tank.  Just a simple old radiator system - none of the downstairs radiators have TRVs so that there’s always a big enough water volume and thermal load.

[dpmiller]

as this is only a tiny cottage with a few rads but high heatloss, should we not re thinking about the system's capacity during defrost, more than just heating power?

[Dan F]

What size monoblock are they proposing? Vaillant specify minumum buffer sizes for de-icing and even if you system is open-loop and doesn't require a buffer, I understand why they would want to stick to manufacturer guidelines.  

 

Can't you accept a buffer but ensue they use the smallest possible buffer size?   Our buffer (for 7kW AHSP) is 25L and wall-hung and doesn't take up a lot of room, but you may get away with a smaller one if they are installing 5kW unit.  See here for an idea of sizes: https://youraccount.71.ekm.net/ekmps/shops/seconsolar/resources/Other/volano-termico-pdc-pensile.pdf

 

 

[DanDee]

1 hour ago, Dan F said:

Vaillant specify minumum buffer sizes for de-icing and even if you system is open-loop and doesn't require a buffer, I understand why they would want to stick to manufacturer guidelines.  

Urban Plumbers never installed a buffer on their V installs

[S2D2]

12 minutes ago, DanDee said:

Urban Plumbers never installed a buffer on their V installs

I think it might have been a typo, they specify minimum system volume, not minimum buffer size. It can be quite large for the bigger units, hence the use of buffers.

[zoothorn]

15 hours ago, joe90 said:

Although I had a buffer in my build there are plenty here that did not and I now question whether mine was actually required? I would simply ask why this expert says the buffer is required, get it in writing and  post it here for others (who knows these things) to agree or pick it to pieces. You can tell them that “other” installers tell you it’s not required and you need to assess the situation. Once their reply is posted here we can all discuss it.

Hiya Joe90, hope things settled down a bit for you. Thx for your thoughts.

 

I'll certainly ask the woman, but I am kinda on thin ice I feel re. their offer reinstated: I can't be super picky, or they drawbridge may come down & offer declined (again). Eggshells, but will try.

 

 

[zoothorn]

15 hours ago, Beelbeebub said:

Can you not get the buffer stuck somewhere out of the way a garage, loft, wherever. 

 

They insist on having one, but you can indicate where it can go. 

 

Maybe if it's too much of a ball ache to fit (say loft), they will delete it?

I've gone round everywhere, intricately measuring. It's just so big the only 2 or so possible places would be ruinous to my small cottage. Loft- This was FIRST place I asked the installer on the spot when he threw this infuriating curveball at me, last August. He went back to ask. The idea refused in an email later, because it needs to be in an insulated place was their reason.

 

Why the installer is so insistant, is beyond me. He even said at this August 22 visit "you could do without, but it's a compromise/ may not work as well/ possible guarantee compromised" (8 yrs.. this decent guarantee, for me alone here with a low income, I cannot compromise). 

[zoothorn]

13 hours ago, DougMLancs said:

We have all radiators in our 110m2 average 1960’s semi and we don’t have a buffer tank. Open loop design. 

Hi DougM, thanks fir your reply.

 

Afaict, the buffer thing is needed on this replacement ('monoblock') ashp.. but is absent, so I assume then not needed on my existing (' split') ashp.

 

In my estimation then, this proposed ashp is therefore not a replacement, but an alternative. But I can't kick up a fuss.. if the offer is foc, & I've got them to u-turn & (reluctantly) admit he offer is still valid. This is the pickle.

[zoothorn]

6 hours ago, dpmiller said:

as this is only a tiny cottage with a few rads but high heatloss, should we not re thinking about the system's capacity during defrost, more than just heating power?

Hi dpm, I can't possibly reply to this as I have no comprehension of it's meaning.

 

A customer, consider old mrs. Miggins at no.73 for example, shouldn't be expected to have to consider engineering minutiae. Surely.

[zoothorn]

2 hours ago, Dan F said:

What size monoblock are they proposing? Vaillant specify minumum buffer sizes for de-icing and even if you system is open-loop and doesn't require a buffer, I understand why they would want to stick to manufacturer guidelines.  

 

Can't you accept a buffer but ensue they use the smallest possible buffer size?   Our buffer (for 7kW AHSP) is 25L and wall-hung and doesn't take up a lot of room, but you may get away with a smaller one if they are installing 5kW unit.  See here for an idea of sizes: https://youraccount.71.ekm.net/ekmps/shops/seconsolar/resources/Other/volano-termico-pdc-pensile.pdf

 

 

Hi Dan F.

 

Now, this has been something I have been considering. And in fact a main reason for the thread. IE the possibility of using a --smaller-- buffer, which I could squeeze in with only minimal impact on my cottage.

 

So. Chaps what about this idea, thus: now in my main big stone 1820 cold-ass shell sittingroom (other rooms attach to), the two sizeable ashp rads... are as good as useless. Not it's fault, simply my cottage's fault.

 

Could I not ask them, that if I turn off these two rads (i do anyway- they're a waste of money & energy, & I have a woodstove if I do want to heat this cold sittingroom) permanently, could a -one smaller- monoblock go in, instead? Assuming that is, a buffer isn't needed OR it has a smaller one like so.

 

Is that a reasonable proposition to put to them??

[JohnMo]

Not sure that would work really, the other heated areas heat would just leach into the unheated room, if the fire off making heating the whole building worse.

 

How long do you run the lounge rads for per day? The rads should be matched to the heat loss - no matter what the heat loss is.

 

Anyway it is so unlikely that any manufacturer would agree to a retrofit partial install - it's just a waste of time suggesting it. More stress when they say no!

[zoothorn]

@Dan F I -think- my system is a 10kw one. A split type, to be removed.

 

Useful numbers there, thanks. I can propose a 25l tank to them with your 7kw figure. At least a starting point.

 

--

 

On a separate note, the aspect I find infuriating about these damn systems, quite apart from what Ive outlined in my awful experience.. is the fact that these extra hardware boxes & tanks, compared to a typical gas CH system they often replace.. are never ONCE mentioned. Only the addition of an outside fan unit. So the customer is blindsided when the installer turns up with large boxes & tanks he insists are to be fitted within the house. It's atrocious, hoodwinking, they're existance IMHO --deliberately not mentioned-- by the mfr. Let alone onward, that these boxes will create intrusive noise excacerbated if sited in cupboard next to beds, in bedrooms. It's a bloody disgrace. 
 

I have R4 on most if the time. I often hear phone-ins moaning about ASHP's, but only about the running costs. Never once, anyone mentioning the ruinous forced-accommodation of large indoor hardware needed with these damn systems. Never once any mention of intrusive noise from interior hardware operating infuriating frost modes 11pm - 7.30 am keeping you awake. It's perplexing that I seem to be the only one, in europe, with this problem. It just adds to my frustration. If I could, I'd rip this damn design disaster out & burn it. I hate it vehemently.

 

Zoot.

 

 

 

 

[zoothorn]

I think actually this thread is exacerbating my stress! No kidding. And I knew it would too.
 

But I have to glean knowledge/ ideas/ opinions, I have no choice but to.

 

Thanks, Zh