Nelliekins

Heating system for an ICF house with UFH

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16 minutes ago, Nelliekins said:

And black/green stripy, since we are doing RWH as well!

 

That stuff is extortionate ..!! Just use 50mm green with a wrap of standard black... 

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52 minutes ago, Nelliekins said:

That said I do prefer Speedfit for elbows etc - no idea why but the twist lock seems to give me some comfort

 

Thats the converse with me as I have to remember if I’ve done the lock up ..! I like the fact that with Hep2O it’s push, twist, done...!

 

Same with compression - I only buy decent ones with copper olives and use PTFE paste on them and never had one go on me. 

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On 29/12/2018 at 12:35, Onoff said:

 

@Bitpipe's IBC thread:

 

 

 

Ta - was a fun project - not dropped a pump in yet as waiting for sparky to finish putting power down there.

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1 hour ago, Bitpipe said:

 

Ta - was a fun project - not dropped a pump in yet as waiting for sparky to finish putting power down there.

 

Looking to copy the IBC part, although we have a window as our secondary means of escape from the basement, as opposed to your door (although a stihl saw and 20 minutes of effort would soon fix that!) 

 

We are having a deck over, and have an egress ladder to get out of the lightwell. There will be a hatch with gas strut assistance as well. 

 

I think your lightwell is bigger than ours, too - we have 4.1m wide by 2.25m front to back, and 2.8m high (7 courses of logix blocks). 

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9 hours ago, Nelliekins said:

 

Looking to copy the IBC part, although we have a window as our secondary means of escape from the basement, as opposed to your door (although a stihl saw and 20 minutes of effort would soon fix that!) 

 

We are having a deck over, and have an egress ladder to get out of the lightwell. There will be a hatch with gas strut assistance as well. 

 

I think your lightwell is bigger than ours, too - we have 4.1m wide by 2.25m front to back, and 2.8m high (7 courses of logix blocks). 

 

IBCs are roughly 1m2 so you could squeeze a few in - we put a mezzanine deck over the top of the IBCs which makes a nice feature.

 

TBH we originally envisaged our lightwell / egress area as a tiered construction but the SE pointed out that it would be easier to just make it a full box, not that much additional cost (just the muck away really as the concrete would have more or less been the same, just different geometry.

 

Once we had the extra space (under the deck) it made sense to utilise it for rainwater harvesting, so the plan was born. The in ground tank systems are probably more robust but do come at a price.

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Posted (edited)

OK, so I have made a start on putting this all together... 

 

IMG_20190104_171703.thumb.jpg.182e5fd1d8c2858eaa8598cac451c364.jpg

 

The PEX pipe adjacent the TMV is a placeholder until I get more check valves, at which time it'll be replaced with copper. 

 

Still waiting for flow switch to be delivered, and connections made to boiler which lives in the room below... 

 

The series of holes in the floor are for the pipes to go up to the hot water manifold, which will be supplied from the TMV. 

 

So, a couple of questions :

 

1. Should I use a Y strainer in the cold input? I had thought about a magnaclean as an option too, but not sure I would see much if any benefit from it? 

 

2. Any ideas on placement of (and recommendations for make/model of) PRV? 

 

3. Am I right in thinking that the F&E tank needs to be 1m+ above the top of the cylinder, and needs to have at least 5% of the volume of the system it is connected to? Realistically that's about 8L I think. 

 

4. The boiler doesn't appear to have an internal pump, so I have bought a 3rd Wilo Pico pump (one for DHW, one for UFH and one for Boiler)... Sound OK? 

 

5. For the UFH side of things, am I going with a set of 3 position valves (one per manifold)? Where do I position the pump and non return valves so that I can bypass the coil and still circulate water to distribute solar gain?

 

 

Edited by Nelliekins
Clarifications

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Posted (edited)
On 03/01/2019 at 09:20, Bitpipe said:

 

IBCs are roughly 1m2 so you could squeeze a few in - we put a mezzanine deck over the top of the IBCs which makes a nice feature.

 

We have 6m of bifold doors that open out straight into the space above our lightwell so a mezzanine deck wasn't really an option. 

 

My plan is to stack the IBCs 2 high to get 4 in there, and it'll all be under the deck... The ladder will go up to an access hatch which will be gas strut supported. If I could make it a walk out area like yours I would do that in a heartbeat, because it'll improve light levels enormously in the basement... 

 

Quote

TBH we originally envisaged our lightwell / egress area as a tiered construction but the SE pointed out that it would be easier to just make it a full box, not that much additional cost (just the muck away really as the concrete would have more or less been the same, just different geometry.

 

Once we had the extra space (under the deck) it made sense to utilise it for rainwater harvesting, so the plan was born. The in ground tank systems are probably more robust but do come at a price.

 

Yeah it was the cost of tanks that pushed me towards IBCs... we are in full - tilt "save every penny we can" mode now... If we have to get another lump of cash from the mortgage provider we won't be able to afford to live there! Hence the economy drive, the homebrew heating system and IBCs.

 

Also bought a set of adapters to utilise our excess UFH pipe (we have about 600m left over, so am running 16mm PEX everywhere, for all the hot, cold and RWH pipes inside I can - fittings are 6 quid a pair and pipe is essentially free now it's paid for!). I find it interesting that every sole that has provided their own quantities for supply have overestimated by a typical 20% (be it the floorboards, or the ICF, or the UFH,...) and the stuff I have quantified has always been nearly exactly right... 

 

Edited by Nelliekins
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Posted (edited)
On 31/12/2018 at 14:01, PeterW said:

I’d mount the stat about 6” above the bottom inlet directly opposite the outlet. It will probably be mid point of the coils for the UFH at that point too. 

 

 

@PeterW I had a thought about mounting a number of DS18B20 temp sensors in the system in tee (actually branch F) fittings, which might help with fine tuning of the system temps and flow rates. Specifically:

 

- 1 in each of boiler flow & return connections to cylinder

- 1 in each of top and bottom connections for coil

 

Is there anywhere else that would be of use to me? 

 

I would still have at least 1 cylinder stat (probably 2, with the second at same height as, or just above, the boiler connection at the top, but opposing) so that I don't need the automaton system to keep hot water and heating working! 

 

Does this make sense? 

Edited by Nelliekins
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Right, I have finally arranged for a plumber to come and connect up the boiler. As of Weds, we should have the boiler connected to both the gas and the cyli^H^H^H heat bank😁

 

I have a F&E tank ready to plumb in above the heat bank, and a manifold ready to connect to the hot water outlet (although that's not needed prior to the boiler being commissioned). I've got a single cylinder stat (a Drayton HTS3) to be positioned approx 6" above the bottom inlet on opposite side of heat bank (as per suggestion by @PeterW), although am still considering having a second stat... I don't seem to be able to find any information on the hysteresis for the stat, but presumably I want it to trigger a demand for heat at around 50C (when the PHE can no longer provide DHW at a high enough temperature), and to tell the boiler it is satisfied at around 65-70C? Do I need 2 stats to achieve this?

 

Once the hot water is working, I need to progress the UFH side of things, which will be done using the coil in the bottom of the heat bank. I'm thinking of 2 pumps - one for the basement+ground floor, and one for the first floor. That separates the 2 types of emitters, and pretty much balances the length of pipe being serviced by each pump (because the basement offsets the integral garage area which isn't heated).

 

So, from the coil, I am thinking we want to have a tee, so that the 2 separate "zones" are parallel. From each leg of the tee, there will be a motorised zone valve followed by a pump, followed by the manifold.

 

Questions:

  1. Will the 2 pumps be sufficient? We're only looking at a relatively low flow rate, with a low flow temperature (25-28C), but it's a lot of pipe to pump through... We've got Wilo Pico glandless pumps following the earlier recommendation
  2. If we close both zone valves, we'll have effectively sealed off the coil - I presume that since the coil will still be getting hot, we will need a small expansion vessel and a PRV - is that correct?
  3. Do we need an expansion vessel for the rest of the UFH circuit as well? IIRC we are intending to run the UFH at 1 bar.
  4. I presume that since there is a drain cock fitted to every manifold, we don't need to add additional drainage points for the UFH - is that correct?
  5. On the subject of drain cocks, I presume we will need one on the DHW side of things, so we can drain down the heat bank?

Anything else I need to know / do?

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