Itho 4 HRV Troubleshooting

fitzie79

I noticed recently that the air in my house seemed a bit stale. I went to the attic tonight and found that the HRV unit isn't running. I turned on and off the power and I can hear the normal sound that the system makes when it is turning on with some whirring and clicking but suddenly the system stops and is silent. It isn't responding to the remote control either to change the fan speed.

Any thoughts on what could be causing the issue or anyone with experience with these systems?

fitzie79

i've been in contact with the supplier of the system but they are not doing hrv systems any longer. they said they'd come back with the contact details for someone who has installed these systems but haven't heard back yet.

i did a bit more digging on the system today and took it apart. there are 2 dc fans in the unit, neither of which are turning during power up. I assume therefore that as it's unlikely both dc fans would fail at the same time that the control panel is likely to be the issue?

I've taken out the control panel. The fuse isn't blown and no sign of anything else obvious on the board. I will try to probe around the board next week at work to see if i can debug it but does anyone know of any other likely problems that i could check for?

CRua1996

Hi,
sounds similar to a problem I'm now having with my Itho unit, except mine tends to kick into life for a period of a couple of hours and then go back not working for the rest of the day.
Can I ask if the PCB was the problem with your board and if so did you purchase a replacement direct from itho?

fitzie79

apologies for the delayed response.

there were 2 issue with mine in the end. A blown power transformer which I replaced initially (i had to take apart the entire unit to access the full PCB). i thought this had sorted the problem and was happy with myself. However, after this transformer was replaced I still had a further problem that turned out was the thermocouples on the PCB. The frost protect stat was gone (i confirmed by measuring the resistance) so the unit was shutting down to protect itself after a few hours. Turning on/off the unit reset this but it was only a temporary solution. I ended up putting a time clockto shut the power every 4 hours as a temporary solution whilst i waited for the replacement parts. This sounds a little like your issue. Getting replacment thermocouples was much cheaper than an entire PCB so might be a good place to start.

CRua1996

apologies for the delayed response.
Reset my unit in early July and it started to work again - well until early last week - and I had forgotten about the problem and as a result didnt see your response until last Friday!
I'm going to remove the PCB this evening and have a look at it. I will test the thermocouples to see if thats the problem.
Thanks again for your informative reply.

fitzie79

No problem.
If I can help further please let me know

CRua1996 wrote: »

apologies for the delayed response.
Reset my unit in early July and it started to work again - well until early last week - and I had forgotten about the problem and as a result didnt see your response until last Friday!
I'm going to remove the PCB this evening and have a look at it. I will test the thermocouples to see if thats the problem.
Thanks again for your informative reply.