Wall mounting a buffer tank that doesn't say it can be wall mounted?

[joth]

I'm looking to add a buffer tank to my FCU zone.

 

I already have a LLH between the ecodan primary loop and the two zones (FCU and UFH). For space reasons it will be far easier to put the buffer in the loft, inline with the FCU zone loop, than try and replace the LLH with one.

My estimate is I need 100-120L buffer, for 8kW ASHP.

At that size, I think it will be much better to mount it onto the gable end wall than load onto the (60 yr old and a but haphazard) loft joists.

 

This one seems to fit the bill, except it doesn't mention that it supports wall mounting.

https://www.plumbnation.co.uk/site/gledhill-stainless-lite-plus-direct-buffer-store-cylinder-120-litre/

 

Can wall-hanging be retrofitted to a buffer tank, or does it need designing in by the manufacturer?

 

Otherwise this one would work - a lot more expensive and smaller, but as well as supporting wall mount it has a better insulation energy rating.

https://www.plumbnation.co.uk/site/vaillant-compact-100l-buffer-cylinder/

 

Also love to have any other suggestions?

I only need 2 port tank (for use in series with the FCU). An immersion heater pocket is a nice to have, but really not necessary (the FCU circuit is only used for cooling).

 

Edited April 15, 2022 by joth

[TonyT]

Build a cylinder stool?

like old airing cupboards?

 

 

[JohnMo]

I would say wall hanging needs to be designed in by the manufacturer.  Generally thin wall pressurised vessel weighing more than a 100kg.

 

 

[joth]

1 hour ago, TonyT said:

Build a cylinder stool?

like old airing cupboards?

 

 

 

Interesting. I'm drawing a blank searching for this. Is the goal to spread load over more joists, or cantilever off the wall?

 

1 hour ago, JohnMo said:

I would say wall hanging needs to be designed in by the manufacturer. 

Thought so. Yeah Easy to find 50L wall hung, but not so many 100

 

 

[JohnMo]

2x 50l?

 

[dpmiller]

https://coolenergyshop.com/collections/buffer-tanks-cylinders/products/cool-energy-120l-stainless-buffer-tank-ce-b120

[JohnMo]

A stool is exactly what it sounds like.  Just something to lift the cylinder above the floor.  In your case build a platform wide enough to straddle several joists, use 4x2 or 6x2 and some ply on top.

[joth]

1 hour ago, dpmiller said:

https://coolenergyshop.com/collections/buffer-tanks-cylinders/products/cool-energy-120l-stainless-buffer-tank-ce-b120

Thanks I had spotted that one in a prior search but (embarrassed to say) the number of ports on it scared me 🤣.

Would it work for plumbing in series with the zone? In another thread @JohnMo suggests it needs to be a vertical buffer with a top port for in  series to work, which makes sense on instinct 

[joth]

1 hour ago, JohnMo said:

A stool is exactly what it sounds like.  Just something to lift the cylinder above the floor.  In your case build a platform wide enough to straddle several joists, use 4x2 or 6x2 and some ply on top.

Cheers! 

Annoyingly (and to my architect's surprise) the joists run parallel to the gable end so the stool would need to protrude out into the loft quite a way to get several of them, and it's loading them right in the middle of their span which doesn't seem ideal either. 

 

2x50 does sound feasible but certainly more expensive.

(But then this whole project is an exercise in good money after bad, as I'm going to need another 100L of glycol mix...🤣)

[joth]

What's the difference between a buffer tank and an unvented cylinder?

Can I just use a UVC?

 

https://www.ebay.co.uk/itm/283876880215

 

That's good value and allows wall mounting. Only downside is both pipe connections are on the underside which maybe suboptimal when used for cooling. (Cold water will just stratify at the bottom

 

 

[Christiano]

I have a Newark Cylinder and I was looking at their site for info about my cylinder, saw they do buffers and I remembered this from earlier.

When we ordered my cylinder it was very much a custom build so I would have thought if if they don’t do what you want off the shelf they would probably be more than happy to make it for you.

Edited April 16, 2022 by Christiano
Correct incorrect grammar from autocorrect.

[ReedRichards]

19 hours ago, joth said:

What's the difference between a buffer tank and an unvented cylinder?

Can I just use a UVC?

 

 

I made a mistake in my original response.  I take it you mean a UVC using the normal DHW connections?

Edited April 17, 2022 by ReedRichards

[joe90]

I have an 80 litre buffer on a “stool” made from 4x2 and thick ply top 👍

[joth]

1 hour ago, ReedRichards said:

 

I made a mistake in my original response.  I take it you mean a UVC using the normal DHW connections?

Yes exactly. ( although if it has a coil I could possibly put the primary in that and the secondary zone through the DHW connections to decouple them and reduce the glycol requirement)

 

[joth]

On 17/04/2022 at 09:36, joe90 said:

I have an 80 litre buffer on a “stool” made from 4x2 and thick ply top 👍

I've sent Newark and Telford and enquiry about wall-mounted buffers.

However i think I can probably make a stool for it. There's an original joist running the down the center of the  loft under the roof ridge, perpendicular to the ceiling joists below it. Rather than view this as an obstacle I think it's an opportunity. I can use some garden sleeper offcuts beside it and a plywood top, and this will transfer some of the tank weight directly into the gable end.

 

[joth]

On 18/04/2022 at 17:56, joth said:

I've sent Newark and Telford and enquiry about wall-mounted buffers.

 

Telford: no wall mount option

Newark: wall mount possible as an option, but only up to 50L

 

Looks like I'll go with my sleeper stool, and cheapest 120L I can find. 

Thanks all.

 

[saveasteading]

As  someone who wrecked a cylinder trying to adjust a connection...these tanks are incredibly thin copper and strong only when full of water.

Unless designed for hanging they have to sit on a base (could be a very strong shelf).

Spread the load as far as you can.

 

 

 

[joth]

On 17/04/2022 at 09:20, ReedRichards said:

On 16/04/2022 at 13:30, joth said:

What's the difference between a buffer tank and an unvented cylinder?

Can I just use a UVC?

 

 

I made a mistake in my original response.  I take it you mean a UVC using the normal DHW connections?

 

Just coming back to this to finally place an order.

 

Again the same question arises: a 120L UVC costs less than a buffer tank.

https://www.snhtradecentre.co.uk/product/gledhill-es-120l-direct-unvented-cylinder-stainless-steel/ vs

https://www.plumbnation.co.uk/site/gledhill-stainless-lite-plus-direct-buffer-store-cylinder-120-litre/

 

Any reason not to use the UVC? It has a complementary PRV. 2x immersion heater and expansion tank...

 

[JohnMo]

Think others on here are using UVC as buffers, Joe90 I believe is, I am using a vented thermal store as my buffer, just converted it to use a 2 pipe layout.

[joth]

31 minutes ago, JohnMo said:

Think others on here are using UVC as buffers, Joe90 I believe is, I am using a vented thermal store as my buffer, just converted it to use a 2 pipe layout.

 

Thanks. It's £299 at plumbnation (fulfilled by Gledhill) so what the heck I've gone ahead and ordered.

I've got a fun project ahead figuring out a bunch of MBSP adapters and draining and refilling a system full of Glycol. 

I hate plumbing 

[joth]

The saga continues.

I decided a 4 port buffer was more versatile than 2 port so ordered the Kingspan Albion 150L instead.

 

Arrived last week.

Boom. It's a few inches too wide to fit through the aperture of my loft hatch.

So enquiry made about returns.

 

But if anyone needs one and can collect from Herts I'll do you a deal.

 

Oh how I hate plumbing.

 

 

[joe90]

10 hours ago, joth said:

It's a few inches too wide to fit through the aperture of my loft hatch.

Surely that’s fixable quite cheaply?

[joth]

2 hours ago, joe90 said:

Surely that’s fixable quite cheaply?

 

Perhaps  not much cost in materials, but the time is an issue, it's yet another project I could do without right now!

 

I was pondering that option this morning. 

It's a premade timer hatch casing and ladder so fixed dimensions.

It's annoying as the available joist opening is 1180x750ish. I wanted to put in a Dollar Hobby ladder which needs 1200x700 opening - just 2cm too large! So our builder went for the next size down (Lyte LELW3) which requires 1130x 550 opening, and only has 510mm clear width inside the casement.

I could temporarily remove the hatch I guess but I the it will result in a lot of making good.

 

Ho hum. Let's see what the return shipping cost is and maybe I'll suck it up

[joth]

Wow one year on! Just to wrap up this thread, I returned the Kingspan Albion 150L and bought 80 Litre "TESY Bi-Light Electric Hot Water Cylinder" and wall mounted that (my first time having fun with Chem bolts!) and using that as a buffer tank fine. 

 

Finally got it all plumbed in last month, and after a lot of tinkering in Loxone have managed to force sensible level of hysteresis from the ASHP in charging/discharing the buffer which looks like it has fixed the short cycling issues when running the FCU: instead of 15 cycles an hour, I'm down to one cycle every 100mins.

 

The controls are a bit complex. I plumbed the buffer in series with the two FCUs but found that when the ASHP is running it would still short cycle as the FCUs are a bottle neck and don't let water through to the buffer fast enough. So I now have a FCU bypass loop (basically open a spare port on the manifold that is piped directly from supply to return) which allows much faster feed into the tank. I have temperature sensors on the zone supply and return pipes, plus in the tank itself, so I can tell if the incoming water from ASHP is cold enough to be "useful" to cool down the tank or not, to control this actuator. As a bonus, this means when the slug of hot water comes through when the heatpump switches from DHW reheat mode back to cooling, I can close down all the actuators to stop this unhelpful 40+ deg water getting into the FCUs or the buffer. (the zone has an automatic bypass across the lot, for this situation). 

 

This is all illustrated in the data:

 

Light blue dashed lines indicate where DHW reheat ran in the middle of the night, you can see the buffer continued cold supply to the FCU during this period, until the ASHP switched back to cold mode and that hot slug of water came through and briefly slightly the buffer (the actuators aren't instant, alas). Each ASHO cooling cycle runs for about 20mins (1kW primary energy draw) and then is idle for 80mins as the buffer supplies cold to the FCUs until the buffer drops to the low temp threshold.

 

I haven't insulated all the new pipework yet, so the buffer is working between 15 and 19deg to avoid condensation. Once I have completed insulation I'll crank that down to 10-17deg or something which should work even better for avoiding cycling.

 

For completeness on the project (bits of which mentioned here) my second FCU is now feeding two rooms, using an electric controlled air baffle to shut off  supply to the lesser used room when not in use (which is also much nearer the FCU so naturally gets priority when the baffle is open), so we now have 3 bedrooms being supplied from this FCU buffer circuit.

 

Edited June 9, 2023 by joth