System pressure dropping on my Ecodan ASHP system

Air Source Heat Pumps (ASHPs)

Last Post by Carbonfree 8 months ago

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spacebiscuit

(@spacebiscuit)

Eminent Member Member

Joined: 1 year ago

Posts: 11

Topic starter 14/10/2024 9:02 pm

I have an Ecodan ASHP, due to some building works the hot water cylinder was relocated and some legs have been run for 3 more radiators which have yet to be fitted.

Hot water has been fine since the relocation of the cylinder around 4 weeks ago. This weeknd I put the heating on, all was fine but next morning when the hot water cycle ran before the heating comes on there was a U1 fault which I believe is a low pressure fault.

So I filled the system to about 1.7bar when heating was on and bled the radiators. I manually put water cycle on and cylinder had hot water.

Next morning after heating had been on before same problem. It seems that when I fill the system within about 30 mins pressure drops to 1 bar or less, however all rads are nice and hot.

Any ideas? Thanks.

This topic was modified 8 months ago by Mars

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cathodeRay

(@cathoderay)

Famed Member Moderator

Joined: 3 years ago

Posts: 2080

15/10/2024 7:50 am

@spacebiscuit - this is an interesting question, why does an ASHP circuit need to be pressurised in the first place? I can't be, as it is with a traditional car radiator system, so the water can get to a higher temperature without boiling, since ASHPs don't get anywhere near those temps. I have a very very small leak, at least I assume it is, in my primary circuit, that causes the pressure to drop very slowly (over days if not weeks) and yet the system seems to run the same whatever the pressure, as long as the circuit has fluid in it, which it does. Maybe the pressure is there to stop negative pressure that would perhaps allow air to enter? Does anyone know the answer?

Midea 14kW (for now...) ASHP heating both building and DHW

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Carbonfree

(@carbonfree)

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Joined: 8 months ago

Posts: 1

15/10/2024 4:59 pm

Hello i am an ASHP Engineer and new to this group. Ecodan U1 code is said to be high pressure fault,which is cause by abnormal water flow on the primary circuit. I recommend get ASHP engineer to come have a look.

This post was modified 8 months ago 2 times by Carbonfree

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