Another ASHP plumbing schematic!

[JulianB]

Just now, PeterW said:

@JulianB you need an expansion vessel on your heat pump circuit somewhere with a PRV. 

 

Thanks Pete! I originally had one drawn in but I removed it as there is one inbuilt in the Pan ASHP which caters for up to 200L (part of the reason why I went with the Panasonic unit as I'm so tight on space!). Was initially going with Ecodan but this swayed it for me!

[PeterW]

Ahh ok ..!

[Nickfromwales]

13 hours ago, JulianB said:

What is a 2 tapping version

A buffer with an in and an out; so it can be in series with the ASHP pump and still promote throughput from that single pump. Your current schematic doesn't allow that throughput, hence my suggestion of the "secondary pump".

13 hours ago, JulianB said:

Secondary pump – if my understanding is correct, this is only needed in this alternative ‘circulation mode’ when wanting to even out floor temps, and hence the inbuilt pump in the ASHP would not play any part

No. That function is performed by the manifold pumps alone.

13 hours ago, JulianB said:

Would the risk of not having this secondary pump be that I couldn’t guarantee circulation between buffer tank and UFH manifolds? Would there be any other risks?

Yes, exactly. The other risk comes from your better half beating you to death whilst wearing three jumpers to stay warm  

13 hours ago, JulianB said:

would a by-pass in parallel with the buffer tank potentially work, or would the ASHP complain about flow rates given that I’ve removed that hydraulic separation between ASHP and my UFH system?

In cooling mode you would ignore the room stats, ergo the system needs no buffer medium in that 'state' as it has the entire system volume, unhindered, so max flow rate will easily be achieved and more importantly maintained. You'd have to have a diverter valve on the flow to the buffer to 'toggle' the buffer in / out of circulation. Pretty easy to do with the buffer you have ( I didn't realise you had already bought so ignore my 2 pipe suggestion ).

13 hours ago, JulianB said:

What would be the main purpose of the auto by pass valves be – if I’ve understood correctly these will bypass to an alternative flow path after a critical pressure is reached?

If you install ( which I suspect you need to ) the secondary pump ( between the buffer and the manifolds ) then when the upper manifold shuts down, and the secondary pump potential is dedicated to the one manifold, and then that gets down to say one zone / loop, the bypass gives a runaway for the excess pump potential....... vs turning that pump down, which you cannot do as the system will need that full potential for cold start ups. The alternative flow path is simply back into the adjacent return, a bit like an infinite loop.   

14 hours ago, JulianB said:

did we say to avoid NO valves as these create quite a large water hammer?

Assuming zone valves not actuators? The norm is normally closed, so stick with those IMO. There would be no hammer, as the ZV's tell the pump to spin, ergo there is no flow during the closing of a 2-port zone valve. 

[Nickfromwales]

Also, what is the purpose of the digital mixer after the buffer? Just to reduce the flow temp in the pipework? If so, do away with it and just insulate the pipes well. In actuality the ASHP flow temp can just be set a bit higher than the target temp, so the digital mixer is redundant tbh.

[joe90]

@JulianB i am late on this thread and confess I have not read it all. I am a Luddite (I don’t like tech) KISS is my mantra (keep it simple stupid ?). I have an ASHP feeding a buffer tank at 48’ (but buffer tank stat set to 35’), the buffer is indirect so water in the ASHP does not mix with the UFH water. The UFH (one zone only) is controlled by one room stat in the hallway, which controls the pump on the manifold. This means the buffer is always topped up to 35’ ready to be used when the room stat calls for heat, only downside is (like a DHW tank) heat is stored in the tank so will lose a little heat, if not used immediately. (But will only loose it into a well insulated house like the DHW tank) I find the heating is not required for at least 8 months of the year so I switch the “heating” off in summer (this means the buffer tank never calls for heat). If in HOT weather I want to circulate the UFH water to disperse heat in the floor next to the South side of the house (big bifolds into a hot conservatory) I “UP” the room stat which switches on the manifold pump but as there is no hot water in the buffer it simply distributes the heat to the North side of the house. I have not needed active “cooling” of our slab up till now but that is a function I have in reserve if global warming really kicks off!!!. I hope this helps?

Edited April 8, 2021 by joe90

[Triassic]

 

I'm going to use your design in my new build.

 

Just a quick question, what are the two multi coloured rectangles on the red hot input to the UFH?

 

which cylinder is that/ make. model?

 

I assume you've shopped around for all the kit, any recommendations on suppliers?

Edited April 9, 2021 by Triassic

[Bramco]

@JulianB is there any chance you can upload the diagram in whatever format you drew them in rather than a pdf?

 

I could do with plagiarising it for our set up - plagiarism being the highest form of flattery   ?

 

Thanks

 

Simon

[JulianB]

On 07/04/2021 at 23:11, Nickfromwales said:

A buffer with an in and an out; so it can be in series with the ASHP pump and still promote throughput from that single pump. Your current schematic doesn't allow that throughput, hence my suggestion of the "secondary pump".

No. That function is performed by the manifold pumps alone.

Yes, exactly. The other risk comes from your better half beating you to death whilst wearing three jumpers to stay warm  

In cooling mode you would ignore the room stats, ergo the system needs no buffer medium in that 'state' as it has the entire system volume, unhindered, so max flow rate will easily be achieved and more importantly maintained. You'd have to have a diverter valve on the flow to the buffer to 'toggle' the buffer in / out of circulation. Pretty easy to do with the buffer you have ( I didn't realise you had already bought so ignore my 2 pipe suggestion ).

If you install ( which I suspect you need to ) the secondary pump ( between the buffer and the manifolds ) then when the upper manifold shuts down, and the secondary pump potential is dedicated to the one manifold, and then that gets down to say one zone / loop, the bypass gives a runaway for the excess pump potential....... vs turning that pump down, which you cannot do as the system will need that full potential for cold start ups. The alternative flow path is simply back into the adjacent return, a bit like an infinite loop.   

Assuming zone valves not actuators? The norm is normally closed, so stick with those IMO. There would be no hammer, as the ZV's tell the pump to spin, ergo there is no flow during the closing of a 2-port zone valve. 

 

Apologies for the radio silence, was burgled a couple of weeks back when I was last writing this response in my lunch break. Unfortunately, they have cleared us out of all our power tools which we have slowly accumulated over the self-build (and more importantly my Novopress pressing tool and 28mm jaws which I was planning to use for this job *tear rolling down cheek*). Hopefully one day they will get what’s coming to them…We had an alarm with PIR CAMs, but they merrily got to work with the Alarm’s siren blaring…On a positive note they didn’t touch my corner full of brand new carefully labelled boxing containing all of the heating system components!

 

Back to plumbing…It is interesting the point you raise Nick regarding the fact that the primary circulation pump in-built into the ASHP might not actually be capable of circulating the fluid downstream of the buffer. Naturally if I can avoid having to put a secondary pump after the buffer tank (and all the other knock on components) I would, partly down to cost and partly down to additional plumbing, wiring etc…however equally I do want to get it right first time and not have to break into the system wet and deal with draining and what not. The risk from my better half and 3 daughters is also very dangerous…the few things I’ve learnt in life is never to cross a Scottish lass (or her offspring)!

 

Understood re. auto by pass valves – do you reckon it is worth me going back to the supplier and confirming whether this ‘off the shelf’ configuration which Panasonic recommend is likely to require the secondary pump (not to sound ungrateful for your advice, more to get it in writing if they think it should work as is). I’ve re-drawn the return leg of this valve to the return of the manifold rather than upstream of the mixing valve? Does that mean I require just one auto by pass valve on the flow side of the manifold. Also, with these manifold pumps (mine is a GrunFos), when not pumping, would they still allow flow through them if say the secondary pump is running, or are they pretty much a shut valve?

 

 

On 08/04/2021 at 10:50, joe90 said:

@JulianB i am late on this thread and confess I have not read it all. I am a Luddite (I don’t like tech) KISS is my mantra (keep it simple stupid ?). I have an ASHP feeding a buffer tank at 48’ (but buffer tank stat set to 35’), the buffer is indirect so water in the ASHP does not mix with the UFH water. The UFH (one zone only) is controlled by one room stat in the hallway, which controls the pump on the manifold. This means the buffer is always topped up to 35’ ready to be used when the room stat calls for heat, only downside is (like a DHW tank) heat is stored in the tank so will lose a little heat, if not used immediately. (But will only loose it into a well insulated house like the DHW tank) I find the heating is not required for at least 8 months of the year so I switch the “heating” off in summer (this means the buffer tank never calls for heat). If in HOT weather I want to circulate the UFH water to disperse heat in the floor next to the South side of the house (big bifolds into a hot conservatory) I “UP” the room stat which switches on the manifold pump but as there is no hot water in the buffer it simply distributes the heat to the North side of the house. I have not needed active “cooling” of our slab up till now but that is a function I have in reserve if global warming really kicks off!!!. I hope this helps?

 

Thanks for the info joe! Reassuring to hear! What sort of solar gain would you say your house gets? I'm really hoping not to have to go down the cooling mode route of the ASHP. I have since had a reply from SALUS confirming that their wiring centre can happily toggle between heating and cooling mode (aside from the ASHP). This will basically switch the thermostats to cooling mode which will have pre set cooling temperature set points, which will then activate a mode where the UFH manifolds are turned on however the  wiring centre doesn't call the ASHP for heat. Sounds like it may have legs!

 

On 09/04/2021 at 08:27, Triassic said:

 

I'm going to use your design in my new build.

 

Just a quick question, what are the two multi coloured rectangles on the red hot input to the UFH?

 

which cylinder is that/ make. model?

 

I assume you've shopped around for all the kit, any recommendations on suppliers?

 

Those are check valves / one way valves, as recommended by our Welsh wizard! I ended up getting everything from Seconsolar, which I found to be great and recommended by a few others on here too. They normally only sell to trade so there was an element of sweet talking involved! In the end I went for their shop floor soiled UVC, which is a JOULE CYCLONE HIGH GAIN 250L UVC

 

On 09/04/2021 at 08:53, Bramco said:

@JulianB is there any chance you can upload the diagram in whatever format you drew them in rather than a pdf?

 

I could do with plagiarising it for our set up - plagiarism being the highest form of flattery   ?

 

Thanks

 

Simon

 

Ofcourse Simon, I wouldn't say it is my finest work, simply done in word copy and pasting symbols etc from here, there and everywhere. Goodluck!UFHv6.pdf

UFHv6.docx

 

Edited April 21, 2021 by JulianB

[joe90]

51 minutes ago, JulianB said:

What sort of solar gain would you say your house gets?

No idea in figures but I do believe it negates any heating (apart from DHW) about 8 or 9 months of the year. I was told I would totally overheat, and if I did not open windows, yes I would but I do close the bifolds into the house to keep the heat out when required. I do believe that location plays a big part and the calculators (IMO) don’t take this into account enough. We  are in a fairly open location near the Atlantic so it’s often windy which stops a lot of over heating. (It does face due South).

Edited April 21, 2021 by joe90

[SteamyTea]

13 minutes ago, joe90 said:

We  are in a fairly open location near the Atlantic so it’s often windy which stops a lot of over heating

Our maximum summer air temperatures are lower as well.  This is because they are set by the sea surface temperature, which in winter are higher than ground temperatures.

Why humans like to live by the coast and not up mountains.

[Bramco]

2 hours ago, JulianB said:

Ofcourse Simon

 

Cheers!!

 

And commiserations about the break-in.  Quite a concern for anyone doing self build if you aren't on site.

 

Simon

[JulianB]

2 hours ago, joe90 said:

No idea in figures but I do believe it negates any heating (apart from DHW) about 8 or 9 months of the year. I was told I would totally overheat, and if I did not open windows, yes I would but I do close the bifolds into the house to keep the heat out when required. I do believe that location plays a big part and the calculators (IMO) don’t take this into account enough. We  are in a fairly open location near the Atlantic so it’s often windy which stops a lot of over heating. (It does face due South).

 

Thanks for that Joe! Looks lovely! I've attached a pic of our current window layout for comparison...the rearward gable faces South East...and we sit at the top of a valley which gives us quite a nice fresh breeze throughout the year! Also hoping the up side down approach will keep the lower level bedrooms cooler.

 

2 hours ago, SteamyTea said:

Our maximum summer air temperatures are lower as well.  This is because they are set by the sea surface temperature, which in winter are higher than ground temperatures.

Why humans like to live by the coast and not up mountains.

 

I know the feeling! I'm originally from a tiny island in the mediterranean surrounded by sea water (although ambient temperatures were quite abit higher!)

 

57 minutes ago, Bramco said:

 

Cheers!!

 

And commiserations about the break-in.  Quite a concern for anyone doing self build if you aren't on site.

 

Simon

 

Thank you! We actually live on site in a caravan, but I was at work at the time, and my wife had popped out to the pharmacy late morning. Oh well, hopefully the insurance company are kind to us!

[JulianB]

[Triassic]

5 hours ago, JulianB said:

I ended up getting everything from Seconsolar, which I found to be great and recommended by a few others on here too.

Out of interest, Did you purchase the pre- plumbed cylinder or the bare cylinder?

[Triassic]

On 09/04/2021 at 08:27, Triassic said:

 

 

I was wondering if you could run the upstairs and downstairs as a single loop and just use one pump and mixer valve etc.

[Triassic]

woops duplicate post.

Edited April 21, 2021 by Triassic

[JulianB]

3 hours ago, Triassic said:

Out of interest, Did you purchase the pre- plumbed cylinder or the bare cylinder?

 

Purchased the bare cylinder, primarily to offer me slightly greater freedom in packaging it under my staircase...if I had the luxury of a pump room, I would have loved the pre plumbed solution!

 

With regards to the single manifold for both floors, it did cross my mind...I wasn't sure if a single pump was man enough for the entire set of runs, and I think I aired on the side of caution...thoughts?

[Triassic]

1 hour ago, JulianB said:

 

With regards to the single manifold for both floors, it did cross my mind...I wasn't sure if a single pump was man enough for the entire set of runs, and I think I aired on the side of caution...thoughts?

 

Half my UFH is up an running using a temporary Willis heater. The pipes are around 600m in length and the pump is on its lowest setting. My other manifold has around 1000m of pipe connected to it. I’m thinking the pump should be more than capable of handling both. I’m also tempted not to buy and fit the buffer tank, given the amount of  liquid already in the UFH system. Recon Renewables quoted for an installation kit, having priced up the parts separately,  I can save another £200. (Every little helps!).

 

[Triassic]

1 hour ago, JulianB said:

 

Just a thought! Did you specify the Aquari Smart Cloud controller? 

Edited April 21, 2021 by Triassic

[JulianB]

13 hours ago, Triassic said:

 

Half my UFH is up an running using a temporary Willis heater. The pipes are around 600m in length and the pump is on its lowest setting. My other manifold has around 1000m of pipe connected to it. I’m thinking the pump should be more than capable of handling both. I’m also tempted not to buy and fit the buffer tank, given the amount of  liquid already in the UFH system. Recon Renewables quoted for an installation kit, having priced up the parts separately,  I can save another £200. (Every little helps!).

 

 

Interesting! I'll need to pull up the lengths of my UFH across both floors, but from memory the fluid volume was ~100L. I wonder if there would be any knock on affects from daisy chaining one manifold to another on split levels...worth some thought if you were able to get the right fittings to connect from one end of a flow rail to the second... 

 

13 hours ago, Triassic said:

Just a thought! Did you specify the Aquari Smart Cloud controller? 

 

In all honesty I was meant to, but it fell off the quote due to budget constraints...do you reckon it is worth having? I intend on doing the entire commissioning of the ASHP and what not myself, so having a hand of God in the form of someone from Panasonic being able to remote in and access settings could ease the pressure. Did you look at shop soiled items? I got my UVC with some slight scratching for around £200 cheaper, still under warranty etc. I believe both UVC and buffer tank came in at £900ish +VAT.

[Triassic]

30 minutes ago, JulianB said:

 

Interesting! I'll need to pull up the lengths of my UFH across both floors, but from memory the fluid volume was ~100L. I wonder if there would be any knock on affects from daisy chaining one manifold to another on split levels...worth some thought if you were able to get the right fittings to connect from one end of a flow rail to the second... 

 

 

In all honesty I was meant to, but it fell off the quote due to budget constraints...do you reckon it is worth having? I intend on doing the entire commissioning of the ASHP and what not myself, so having a hand of God in the form of someone from Panasonic being able to remote in and access settings could ease the pressure. Did you look at shop soiled items? I got my UVC with some slight scratching for around £200 cheaper, still under warranty etc. I believe both UVC and buffer tank came in at £900ish +VAT.

I’m also going to instal and fit the ASHP and all the plumbing myself. I was thinking  what I save on the buffer and pump, I’d spend on the Smart controller. I’m told it allows you to carry out tweets to the set up from your phone and gathers a host of operational data, which can be useful in ensuring the most efficient operation.

[JulianB]

I managed to make a start on the plumbing this weekend after having put it off for a while  - I sourced the wrong type of pressing jaws for my Novopress gun, so all joints are currently loose (and more importantly can be taken apart again if I've missed something!). Comments welcome!

 

 

 

 

[Bonner]

Very tight but very tidy ?

[PeterW]

I would check you can get insulation on all that pipework but a nice tidy job. Do all the water pipes go upward from those manifolds .? Can you offset them so they are staggered and the cold doesn’t go over the top..?

[JulianB]

33 minutes ago, Bonner said:

Very tight but very tidy ?

 

Thanks! Things get a little busier once the UVC comes in!

 

14 minutes ago, PeterW said:

I would check you can get insulation on all that pipework but a nice tidy job. Do all the water pipes go upward from those manifolds .? Can you offset them so they are staggered and the cold doesn’t go over the top..?

 

Thanks Peter - I was thinking worst case scenario would be that I insulate just the flow runs? All the pipework is within the thermal envelope of the building if it helps...would be it a show stopper if half of the pipework was uninsulated?

 

All cold water pipes go upwards, but I've stepped the hot water manifold outwards above it so that I can slot the cold water pipes underneath without too much fuss; taking my inspiration of a photo shared on here a while back  

 

Photo added of 250L UVC in the picture to give some perspective on that side of things!