Posted by: @l8again

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Wow - I seem to have wandered into a minefield here. It would seem that the industry is as confused as I am!

It’s quite clear to me that this ultimately comes down to risk appetite, and that risk sits with the homeowner. The risk, IMO, in this instance is extremely low.

Even if you went against manufacturer guidance in this specific instance (not that I am advising this) and convinced an installer to fit the unit, you haven’t done anything that affects how the machine actually runs or places additional mechanical or thermal stress on it. You’re not altering the refrigerant circuit, not changing operating parameters, not modifying controls and not doing anything that impacts performance or longevity of the unit. If the gas was to leak, it's had nothing to do with where it was cited.

So on that basis, it’s hard to argue that the product warranty itself would be voided either despite going against guidance, because the appliance hasn’t been installed or operated in a way that compromises its function or integrity. The heat pump will behave exactly the same whether an air brick is 600mm away or 1.2m away or at the other end of the house.

Tricky one this and it's a massive grey area that needs some of sort firm regulations to make things clearer to everyone because R290 heat pumps are going to be the standard for the next few years.

@editor I suspect that a more significant risk with regard to R290 possibly leaking from a system relates to the likelihood of any insurance policy being ‘weighted’ or possibly refused by the underwriters as they are likely to pick up on even the slightest sniff of additional risk that may or may not even exist.

At the time of our surveys for a heat pump installation in summer / autumn of 2022, it was apparent to us that the various potential installers were not prepared to install a system that employed R290 as we have drains, air bricks, a door and a window all within the proposed site. We had a system installed that employs R32 as this was a route with the ‘least line of resistance’ and provided peace of mind in case there was any real chance of increased risk from R290. Regards, Toodles.

Posted by: @toodles

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have drains, air bricks, a door and a window all within the proposed site

I would imagine most town, city and urban properties will have exactly that situation, which is why it’s so concerning that there’s been such a huge push towards R290 without clear, consistent regulations in place. I had no idea until looking deeper into what this post raised.

To my understanding, many major manufacturers are planning to cease producing R32 units in favour of R290, yet the real-world implications for typical UK housing stock don’t appear to have been properly thought through.

I genuinely don’t understand the people running the show here. The lack of joined-up thinking, foresight and practical planning is distressingly evident, and it’s homeowners who are often left trying to make sense of the mess.

Just to demonstrate how silly this whole HP R290 gas safety debate is, my Samsung R290 heat pump tumble dryer is happily sitting underneath my gas boiler in the utility room.

Anyone looking down on Earth from afar would think that there is no evidence of any intelligent life forms on our planet.

@l8again Hahah, this just makes me smile, i wonder how much refrigerant they hold? Also the Haier OEM tumble HP driers were getting recalled for exploding so at least the rule here would make sense not to keep R290 in the house as the risk is real enough the manufacturer recall them all on a safety issue.

https://www.which.co.uk/news/article/urgent-safety-notice-issued-for-85000-tumble-dryers-aHaXU4u7eTiV?utm_source=chatgpt.com

I still maintain its about risk assessment and justification as there is nothing in Law, just follow the manufacturers guide and place the HP in the middle of the garden or seal an air brick, move an air brick and place against the wall.

Also, i got to say, who measured that if the wind was a warm 3mph down the side path of your home that is 1.3m wide and fenced in that the gas bursting would not get moved 2m further down and would not go in the air brick 1.6m away? the whole ally is a risk, anything area lower that can pool the gas and the air can move or gas float it is a risk, but the risk is for a very short time as the gas would boil off rapidly enough. At least you can have the lighter fluid in the cupboard next to the oven (300gms) the BBQ bottle in the shed 1m from the house 3kgs and the R290 tumble drier in the boiler cupboard probably 400 gms.

Remember Part P requires keeping to the manufacturers instructions and is a legel regulation.

@ringi Yep, but doesn't Part P only apply to the electrical aspect and has no baring on the mechanical or gas aspect of the works?  Regardless though block the air brick, move the air brick or install away from the side of the building, easy....

R290 minimum 1m away from drains and air bricks, .5m for widows/doors Electrical isolator same distance. Refrigerant volume in HPs from .8kg  Tumble driers use R134a although some newer ones use 290 or or mixture but the quantity is only around 100g. Most fridges use R600 butane but again very little in volume. Latest AC air to air are starting to use 290 but electrical componments sealed and fan goes into high speed mode if inbuilt detector detects a leak so as to disperse.

Posted by: @ringi

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Remember Part P requires keeping to the manufacturers instructions and is a legel regulation.

Can you provide a reference please for that statement.  Nowhere can I see this within the actual regulations and neither can I find the work 'manufacturer' in the approved document, nor when I read through although I concede it possible I missed it.

I would actually be quite disappointed if this were the case, because it would let the installer 'off the hook', whereas the regulations, particularly those which concern safety typically typically put the onus on the installer to 'get it right' which is sensible since only the installer knows the full context and thus she/he is the only one in a position to assess risk.

@ashp-bobba I can well see the argument for moving an air brick to end up with a compliant R290 installation; however, my reading of Building Regulations, and I am happy to be corrected, is if the relocation results in insufficient ventilation, damp issues, or violates safety standards (such as blocking ventilation), it will breach Building Regulations Part F (ventilation). 

• Blocking or Reducing Airflow: If you move the brick and, in doing so, reduce the overall ventilation capacity (which must be at least 1,500 mm² per metre run of external wall or 500 mm² per m² of floor area), you are in breach.

Whether anyone would notice or care is a different matter, but the same can be said for having an air brick in a R290 HP protected zone 

The answer is to change the rules not fudge a way around them.

@l8again I agree fully, so what we would do is offer you an R32 unit or fit the unit in another location. My point last time is if you have absolutely no choice then you could relocate the air brick 500mm further up the wall with a much higher flow brick if needed or calculate the F/A of the air bricks all together to see if you can afford to loose one or just move one, as mentioned on here before air bricks are very often over subscribed, a rule of thumb is 1500mm2 - per M of wall , most standard air bricks are 7000mm2 so every 2m is normal but you can get whole screen versions or high flow versions such as what I have attached below:

Also note: air bricks are under building reg part C, part F will not apply to air bricks and sub floor ventilation.

https://products.titon.com/product/q-plus-high-flow-brick/