Ground Source Heat Pumps

beardymarrow

JHen1 said:

JHen1 said:

My IVT HT Plus C7M G3 has just alarmed with the following error 
HTF (coll) out
I had this serviced Sept 2020. Is this anything to be concerned about ?

I've acknowledged the alarm but the Alarm indicator is still red

Hi JHen,
Can you send the exact error, as I don't recognise that one exactly, so it could be a few things. The alarm will stay red all the time the error is present. It has to be fixed and then acknowledged to go away. 

JHen1

Please excuse the quality as the display panel flickers so the message looks a little scrambled

JHen1

According to the manual its "HTF out under limit T11 (GT11)" - Possible causes -T emporary low heat transfer fluid temperature, Too low flow on the cold side or The minimum heat transfer fluid temperature has been set too low

beardymarrow

Thanks. First thing I would do is to check the filter on the pipes that go underground to check if that is restricting flow. That's the easiest thing to do. What are the GT10 and GT11 readings?

JHen1

Thanks beardymarrow. GT10 is 1.3 and GT11 has ---
When you say "check the filter on the pipes that go underground", where would I find that ?

beardymarrow

Ah, that looks like your GT11 sensor is faulty (or the wire to it) rather than an actual real problem then if it's just giving --. That doesn't match the "HTF out under limit" alarm though, as with that alarm you should be getting a reading, it'll just be really low.
I'd still check the filter first as that's easy, before checking the sensor.
The GT11 sensor is a small round cylinder taped to the out from the heatpump to the underground loop. GT10 is the sensor on the input side of the same loop. You should see two black foam wrapped pipes in the heatpump that go to the outside and they will both have a wire going to underneath the foam with the sensor on the end.
Next thing I would do is to check the wire from the GT11 sensor to where it connects into the mainboard, there might be a cut where it's vibrated against something metal, or the connection to the board has come loose. Failing that swap the sensors over and check if the problem moves to GT10, that'll prove the sensor or wire is faulty. Then you just need to buy and fit a new sensor if it is that.
This is what the sensor will look like, and as I say it'll be taped to the side of the pipe going out to the underground loop.
https://jsenergi.co.uk/ivt-spare-parts/by-model/ivt-greenline-d-e-9/ntc-givare-2000mm-molex.html
Here's a copy of the manual
https://u.pcloud.link/publink/show?code=XZCjGYXZPcHhhW7eRNR8qHTFFgu8fSh3Y86X - This show how to check the sensor (Page 38) and how to check the filter (Page 30 shows the process for the heating system side filter. The ground loop filter is the same process, but just on that pipe).

JHen1

Very much appreciated beardymarrow. I've checked the 1.4 manual against the 1.1 manual and the alarm I have is in the 1.1 and it's the same as the one you highlight on page 38, but with different text.
While this is faulty - will this cause any adverse affect to the GSHP ?
I've never changed the sensor - but I assume I need to power off and flip of the fuse ?
Also according to the 1.1 manual on the HT Plus C, the hot side particle filter it is located outside of the heat pump. Would this be the filter and the GT11 sensor?

or this sensor?

JHen1

So just reread you post and it looks like the second picture is the GT11 sensor.

beardymarrow

Hi JHen,
That will be the hot side filter. You need to follow the same process as in the manual for the hotside filter, but for the cold side one (on the loop that goes underground outside). Sorry if I wasn't clear. On my E that is inside a rectangular piece of rigid foam insulation, just outside the actual pump itself. The manual shows where the cold side pipes come out of the pump so you should be able to trace them to the filter.

The GT10 and GT11 sensors will look the same as those ones, but the ones you've found look like the ones on the hot side (GT1 and GT9). The GT10 and GT11 sensors are inside the GSHP cabinet on my E9, and I assume they are the same on your C. They are on the cold side pipes.
To replace, you can just switch the pump off on the button on the panel. No need to flip the fuse, but if you know which one it is, it can't hurt. I've turned mine off only on the switch before and then accidentally pressed it when leaning in to do something :-)

Whilst it's faulty, if something else goes wrong with the unit, you've not got the safety net of it monitoring the temp difference between GT10 and GT11 which could cause something to fail big, instead of the pump switching off to protect itself if you get a blockage or pump failure or something.

JHen1

Ok, from your last post I think this is it, the sensor in my last picture is also shown here