Posted by: @editor

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I have an 11kg propane cylinder 1.5m below our kitchen window feeding our cooker. 

Right!  Obviously, insisting on clearances for bbq cylinders is impossible to enforce but installations of HP can be. It seems weird that we can have metres of natural gas piped inside our house but not a small amount of propane outside - is it a smell thing?  Propane has no smell??  How long would a complete vent of propane take to dissipate outside?  Anyway gas explosions are very news worthy, BBQ not so much, at least I can't remember any being reported.

Propane is denser than air https://en.wikipedia.org/wiki/Propane so any leak is likely to spread laterally and not vertically.

However, something else to watch out for is any airbricks in the vicinity of the heat pump location. I've got one near my heat pump but it was discounted as irrelevant because the wall cavity had been filled with insulation.

Posted by: @andrewj

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Posted by: @editor

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I have an 11kg propane cylinder 1.5m below our kitchen window feeding our cooker. 

Right!  Obviously, insisting on clearances for bbq cylinders is impossible to enforce but installations of HP can be. It seems weird that we can have metres of natural gas piped inside our house but not a small amount of propane outside - is it a smell thing?  Propane has no smell??  How long would a complete vent of propane take to dissipate outside?  Anyway gas explosions are very news worthy, BBQ not so much, at least I can't remember any being reported.

 

I did once look for actual regulations governing this and couldn't find any.  What I did find was a couple of sites which said (fairly convincingly) that there were in fact no regulations, but manufacturers are playing safe.  I suspect that may be the case.

Obviously the internet is full of lies and half truths, but usually regulations can be found if you try, which I did.

I therefore now genuinely suspect that there are no regulations but somehow manufacturers have alighted on a common position (perhaps based on gas regulations as suggested upthread).  Maybe thats actually the industry being responsible.

As far as I can see there is nothing to stop you putting an R290 ASHP below a window, even if it opens.  The protective zone applies, so far as I can see, when any part of the ASHP is above any part of the window.  Since propane is heavier than air that does actually make some sense.

You can have a 13kh propane cylinder on a boat and at least a 6kg one in a caravan.  Certainly in the case of the boat there is a requirement for drainage holes for the gas from the storage area to a safe space outside the boat.  You can still pipe it into the boat).  That seems sensible, whether the fuss about the ~3kg of propane in an ASHP is sensible I do not know.  

I don't have any feel at all how many installations become problematic if you interpret the 'rules' as allowing ASHPs below a window (which is a pretty natural siting).  Doubtless there are some, but is this a major issue in reality?   I guess that, until someone shows that it is a major issue, the rules are likely to stay as they are!

@andrewj I understand there are R290 ice makers allowed indoors! Ok less R290 ( I believe Heat pumps have just over a kilo of R290). In my case it was almost impossible for me to have an R290 HP in a reasonable location. I think there needs to be a rethink of these rules. The explosive range of propane is quite small (2.1 to 9.5%) so it needs the right mix and a source of ignition to explode.

Posted by: @jancold

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I think there needs to be a rethink of these rules.

One of the problems appears to be that they don't actually appear to be rules (in the sense of something created by some authority - see my earlier post)!  If this is the case then its a fairly crazy situation because either they are needed in which case they should be rules, or they arent!

However as all heat pumps seem to conform to the same 'rules', presumably the Heat Pump manufacturers Association or something of the like concocted them, probably to avoid any liability claims. 

Posted by: @jamespa

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One of the problems appears to be that they don't actually appear to be rules (in the sense of something created by some authority - see my earlier post)!  If this is the case then its a fairly crazy situation because either they are needed in which case they should be rules, or they arent!

However as all heat pumps seem to conform to the same 'rules', presumably the Heat Pump manufacturers Association or something of the like concocted them, probably to avoid any liability claims. 

It's quite possibly the case.  As an example, Vaillant's Arotherm plus has 0.6kg of R290 in it ( https://www.vaillant.co.uk/advice/understanding-heating-technology/heat-pumps/natural-performance-with-r290-refrigerant/ ) If that is suddenly released into the area around the heat pump it will have some explosive potential but significantly less than any typical BBQ canister, except for one that is nearly empty.  How long does that 0.6kg hang around for without dispersing due to breezes and general outside air circulation?  

It's quite possibly a concern about it creeping into a house, drains or other conduits and not being dispersed.  If it's aroma free then a householder isn't going to know, as they would if they had a gas leak.

In this country, are those "protective zones" just guidelines in the lack of any regulations??  I was hoping someone who had installed one in an area with windows and doors would comment - or an actual installer would chip in.  

I'm hoping that it isn't an issue at my house because there isn't a suitable alternative location so I'd end up with an R32 model.  Not that that is an immediate problem and may, ultimately, only become an issue for a future owner when it reaches EOL.  The Daiken is blooming ugly though. 

Posted by: @andrewj

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I know they are perfectly acceptable at the moment but the global warming value is quite high and I've read some, frankly confusing, reports that it is being phased down.  This sort of implies it might be harder to purchase/install in the future, say post 10 years or so.  I can't find any definitive answers on this so wondered if anyone closer to industry had any idea.  Note, I'm not getting confused with R22, I'm definitely talking about R32.

When I was getting quotes middle of last year they all initially quoted R32 units but because of the above I said I wanted an R290 unit it wasn't a problem for any of them they changed the quotes to R290 units except  Octopus who at the time only had Dakin R32 units.

I was surprised no one offered a R290 unit inthe first instance as I don't recall any real change in price of the unit? 

@irmartini My first foray into actual choice of the heat pump to be fitted was when Octopus carried out a survey in early 2023 and they were only fitting Daikin then. Doing ‘due diligence’, I looked at other possibilities and ruled out Vaillant as their guidelines (I won’t call them rules or laws) appeared to preclude using a heat pump that used R290 under the circumstances pertaining to our siting option. We have doors, a window, drains and air bricks in the area. We have ended up with R32 and Daikin which placed no such concerns upon us. Guideline, recommendation, law or regulation - the matter needs to be resolved! Regards, Toodles.

There is one exception to the ‘gas outside the house presumption. Probably many others may exist in one form or another.

I believe Daikin manufacture a heat pump which rather than bring the FLOW and RETURN pipes out to the HP the system brings the REFRIGERANT pipes into the house. This presumably avoids the hazard of freezing pipes and glycol solution.

However I’ve only seen this method used on an R32 heat pump. It was used on a house in Scotland.

@sunandair I think this may be what is referred to as a ‘split unit’; the heat pump main unit is outside and there is a ‘hydrobox’ installed inside. I think the external box is a little smaller but the system requires a fitter with F-Gas qualifications to install / commission the system. I may be wrong of course… Regards, Toodles.

@toodles thanks for that toodles. I was hoping you might have known something about this Daikin . It did appear to have a hydrobox fitted as soon as it came in through the external wall. Sounded like a good idea for very cold climates.

Just to follow up after my design consultation visit.  Apparently for a R290, positions of drains don't matter but doors and windows do.  It can go under a window but not next to one (or a door) if it intrudes in the keep-out zone.  It would seem "they" have recognised that drains are full of flammable gases anyway so no longer insist on this point.  If I get any further clarification next week when Octopus are around I'll add another message.