@netdonkey did you do it via the grant BUS scheme?

@ashp-bobba Lower pump, bottom right

Posted by: @ashp-bobba

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@netdonkey did you do it via the grant BUS scheme?

Home Energy Scotland scheme

@netdonkey well I would imagine you would be covered in the same way. 

@netdonkey ok, So its sounds like the the Wilo is doing the main ASHP F/R and is set to full speed.

engineer is booked to come Thursday.  One thing I have noticed is that the circulation pump is pushing water through at 0.8m3/h which is roughly 18lpm.  Flow sensor still says around 7lpm.  I’ve had a Quick Look outside where the ASHP is and found the attached.  Is this another filter?

Yes. It's usually called a strainer.

It's also uninsulated,
...and the adjacent pipe insulation isn't sealed.

This will allow ingress of rain water between the pipe and insulation, rendering it useless.

Water will run down the outside of the pipe, absorbing heat and throwing it away on the ground.

What markings are on that external insulation?

@transparent I will have a look first thing.  Tis rather dark and wet.  Tried to open the strainer with one hand while holding a torch so I could see what I was doing!!

Hi Net,

Glad you have found the strainer, hopefully its nicely blocked, quick clean and then get some flow rate back 

Opening that strainer, will of course lose fluid from the system and introduce air.

You don't have isolation valves on either side of it which would've limited those effects.
But have a look at the pipework and see if you have any manual valves which stop both flow and return from going to the external unit.

I've not previously met a strainer on an external run.
Perhaps it's a requirement stipulated in the manufacturer's installation guide.

Please take a photo of the strainer so we can see it  

When you replace it, take care to ensure there's no grit or hair on the seal, which is probably a neoprene rubber o-ring.
Just run it under the tap to get rid of debris.

I normally remove any o-rings which have needed cleaning, dry them with a piece of kitchen paper towel,
and then lightly smear silicon-grease on them before re-fitting.

You may not have such a consumable, but I've previously made do with vaseline or olive oil !

The idea is to ensure that the o-ring smoothly glides back into its seating without being pinched.

Do you know if the installer put any additives into the loop which supplies your radiators and the heat pump?

There might be an anti-freeze, such as glycol,
or perhaps a corrosion-inhibitor, such as Fernox F1 or Sentinel.

This should be mentioned in the commissioning notes,
and there's often a sticker taken from the bottle of inhibitor which gets put in a prominent position close to the braided refill-hose.

There may be no additives at all, so don't waste too much time looking!

Sadly the strainer was clean but the act of opening, removing and closing again has bumped the loom lpm up to 8.5 which has stopped it from tripping out.

The insulation is armacell Armadale but looks like all the joins haven’t been taped.

There is a additive in it called

something like x.509.  There is a spare bottle of it in the shed I will look at later.

plumber is coming out Thursday but I’m not sure what’s left to check do for him to get the lpm up.

OK, so things are heading in the right direction.
There may still be some air in the pipes which has yet to come out.

Or you could now be approaching the flow limit which is imposed by the very nature of the pipework.
The bore and sharpness of bends become more of an issue once other factors are removed.

Brass features, such as valves and filters, are available in 'standard' and 'full bore' alternatives.
Each 'standard' fitting imposes a restriction which reduces the flow.

Armacell is a good make of closed-cell Class-O nitrile-rubber pipe insulation.

But they manufacture both for internal and (UV resistant) external use.
It matters which part number is printed on the black insulation.

They do have an adhesive tape for sealing joints,
but personally I'd also be applying a bead of mastic around the end of each section of insulation too.

I can't find any reference to 'Armadale' in their literature.
But I know it's a town in Australia.

X.509 is a category of data encryption.
It would be 'interesting' if you've got that in your system