purging air from ASHP/UFH System

[Conor]

I had to disconnect and partially drain down our system to move our ASHP to allow renderers access to the wall behind.

 

The best isolation I could do was at the buffer, so the only pipework drained was the mono block, and the 10m of flow and return pipework. All in, just a few litres of water.

 

There's a air valve on the flow from the ASHP to the buffer. Nothing else. I'm going to take the opportunity to fit one on the flow at the first floor UFH manifold.

 

What's the process for refilling / purging the air? Can the two bottle valves handle it? Do I just open all the valves I've isolated (buffer in and out valves, all manifolds), fill to 1bar and see what works it's way out? My concern is how do I get the air out of the ASHP itself? Just start up the pump?! 

 

I don't have a filing pump, so will be using the mains fill loop.

[JohnMo]

You heat pump will have an air release valve within the monobloc. It will also have a air purge cycle, where it runs the circulation pump in a pattern aimed to move and release air.

 

If you have a buffer you really should have a bottle air trap at the top of that.

 

So fill the loop with water and initiate the purge cycle - you will need to read the manual on how to do that. Then let it pump to the buffer and back. Cycle will be 10 to 20 mins

 

The high point in the system should have an air trap as well.

[Conor]

Perfect John, thanks. @dpmiller have you done this before?

Edited October 12 by Conor

[dpmiller]

no purge cycle or anything like it on the iVT.

 

Yep just fire it up and your bottle valves will sort it. Only open the isolators on the UFH manifold when you're sure the hissing has stopped tho...

 

/ worst that can happen is it trips a flow error

[Nickfromwales]

5 hours ago, dpmiller said:

no purge cycle or anything like it on the iVT.

 

Yep just fire it up and your bottle valves will sort it. Only open the isolators on the UFH manifold when you're sure the hissing has stopped tho...

 

/ worst that can happen is it trips a flow error

Defo keep the isolators to the UFH closed whilst purging and venting. Just don’t forget to open them afterwards. 

[Conor]

All sorted in the end. Two idiotic moments turned it in to a bigger job that nesecarry. 1. I missed a second isolation switch for the control module on the tank. 2. A sticky valve on one side of the pump that I didn't fully open. All Woking good. I've a potential tiny leak tho on the Flexi pipe to the ASHP. I need a bigger spanner.