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Oct 24, 2019
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Hi all!

I'm a new homeowner in a new build that's been fitted with a Danfoss series 7 HIU. We've had no problem with the hot water since moving in in the early summer and I thought it was time to check the heating before it got too cold!

Low and behold....the radiators won't heat up. Thermostat is fine so I did some torubleshooting and am pretty sure the system isn't sufficiently pressurised.

It's currently reading 0.5 where everything I can see online says it needs to be 1.5 to 2 ideally and that the system won't activate below this.

I've been desperately trying to find how to fill the system to the correct pressure and came across this thread:


Frustratingly the photos have expired so I can't see where the filling loop is and how to access it!

Any help would be much appreciated!

Thanks
 
Absolutely thanks for replying! It looks exactly like the image in the instructions you linked too.

I've also added a picture of the specific model number.
20191025_060151.jpg
20191025_060201.jpg
20191025_060145.jpg
20191025_060227.jpg
 
If it is a new build and you only moved in this year, you should contact the builder to correct the issue, ensure that the system has been properly commissioned and demonstrated to you.

With respect to filling, the filling loop is normally left detached from the system and often is not there or lost. You should be able to identify the filling points by the black cover caps, then purchase a suitable loop. The heating side circuit pressure should be around 0.75 to 1 bar.

However, if the system was properly commissioned this year, it should not need re pressurising in October.

Be careful with fiddling with the unit too much. They are a lot more complicated than they look.
 
Filing loop is the silver braided hose

Atm it’s not connected

One end on the red handled valve in the front

The other end in the back on the sliver valve with the black Handel

Don’t mess with the front black raised knob
 

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Filing loop is the silver braided hose

Atm it’s not connected

One end on the red handled valve in the front

The other end in the back on the sliver valve with the black Handel

Don’t mess with the front black raised knob


Thanks for this! I've contacted the builders about this but knowing their turnaround time it might be next winter before it gets done.

I had a go at connecting the filling loop and oddly it doesn't seem to fit the valve. It won't go in any further than the image below and the thread on the loop is too small for the thread on the valve??

20191025_165530.jpg

20191025_165543.jpg
20191025_165609.jpg
 
Both ends of the filling loop the same ?

Just detached the loop and the end that was attached at the back fits the valve at the front but the other end doesn't fit at the back, after looking at it the end pictured above is ever so slightly wider than the other end that was secured
 
That’s a strange one you can’t see any other valves that it might fit on

Any pics of the left hand side ?

It is really odd, there doesn't seem to be anywhere else to use it?! I've tried to connect it to the valve at the front so many times and it just is slightly too large. It is also slightly too large for the back valve. I'm at a loss? Unless the loop is faulty and one end is machined incorrectly which would explain why the system was never pressurised properly?

Pics of the left hand side below.

20191025_184502.jpg
20191025_184505.jpg
20191025_184508.jpg
 

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