Just no Hoval RS 250

1. I have a Hoval Homevent 250 since 2005 and am very satisfied. Compared to the other offers with geothermal exchangers, I chose this one. The only thing I have done is add additional silencers both to the rooms and to the outside (very sensitive neighbor). The air rehumidification works very well. Odor transmission -> none.

I now have a malfunction and therefore did some research and came across this post.

2. Regarding the G4 filter: Martin 206: do you install the filter outdoors? What did you sew the bag from? I don't see any seams in the picture. I look forward to more info. Where did you buy the G4 filter bag?

3. I find the "self made" filters in the device very interesting. Has anyone tried that before?

Sorry, I don’t check here regularly.

What kind of malfunction? Only LED red? Or sounds from the rotor?
Your 2005 model was probably delivered with the less durable bearings...

Regarding point 2.
Until this year, my supply air pipe ended in the shed (by the carport). I simply inserted it into the pipe, pulled it over the edge, and then pushed the end piece with the fly screen back on.

The filter is simply sewn from G4 fabric by the meter. I buy it wherever it’s cheap. Ideally about 20mm thick and progressively structured fleece with Ökotex label or other certification regarding being free of harmful substances. (Search on Ebay: Filter G4 progressiv)

Yes, simply sewn. Using the circle formula, I determined the circumference from the diameter:
3.14 × diameter, so for the 200 pipe about 62.8cm + approx. 1cm for the seam.
Cut 1m × 64cm, just sewed the long and one short side – done.

Regarding point 3.
I wouldn’t bother with self-made filters inside the device.
These parts are available online from independent providers for free ... so about €30 including shipping.

Fabric by the meter doesn’t work inside the device.
But you can sew something for self-made filters for the valves and the fresh air intake outside using that.

link removed by moderation; construction expert

Regards
-Martin-

Thank you Martin!

I now have an offer from Hoval: material costs about €1000, goodwill discount 10%, since the device is already older. However, no one from Hoval ever told me that there is a goodwill period that expires, during which it would still make sense to replace the rotor.

Kindly, a Hoval technician told me that if you don’t have two left hands, you can check it yourself and open the device. You just have to be careful not to tear off the cable when pulling out the rotor.

The device is really easy to open. I also took documentation pictures in case anyone is interested. The bearings are perfectly fine. You could also swap the top two bearings with the lower ones; the top ones are basically not stressed. But this was not necessary. The rotor did not turn because the motor that drives the rotor is broken.

The inquiry to Hoval about the motor is ongoing; I do not have an offer yet.

As a curious person, I then bought a geared DC motor for €10 from Neuhold Elektronik. The drive gear fits well on it. I then mounted the motor with a provisional fixture and operated it via my lab power supply.

And it works!!!

In the first days, the system went orange about once a day. Now it runs five days without any problems. I suspect that the Teflon lip seal still needs to be replaced.

I will run a continuous test for one month and decide whether to permanently install a speed controller on the device (cost a few € on Amazon).

I believe that I can live well with a fluctuating humidity range. I think the important thing is that the rotor turns at all, as this prevents the air from drying out.

Best regards Dominik

I should have paid 1,070 EUR (for a rotor replacement) ... then I happened to meet a Hoval employee (senior level) on the web who said it should be covered on goodwill. The invoice and reminder arrived ... only when he inquired again was the invoice canceled and I was informed that Hoval would cover the entire cost. That's probably not the usual way... :eek

Yes, the device is easy to open and is also quite accessible inside.

Is the motor really broken? Or rather its control. If the motor, then I would install an equivalent one as a replacement (possibly as a spare part from Hoval - if not hopelessly overpriced). The rotor control is certainly done for various purposes ... including to prevent icing in winter. Possibly also to prevent too high humidity in the device? Consequential damage could definitely be conceivable here.

Regards -Martin-

Unfortunately, we also have such a HOVAL device in use. So far, we have apparently been lucky with the rotary heat exchanger. I think the geothermal exchanger with a pre-filter that was installed before also helps us somewhat. However, we repeatedly have problems with the fan motors. Now it’s happened again; we are supposed to pay over €360 for a new fan (without installation). Hoval charges a hefty price for their parts. One more comment about moisture recovery: it doesn’t work at all for us. No matter the setting on the control panel, the relative humidity always drops rapidly in winter. Only by using several powerful room humidifiers can we raise the relative humidity to 40% at all. For our next house construction, or when the device is completely broken, we will definitely not buy a Hoval device again.

So now the drive motor of the heat exchanger has also failed on our end. The motor has a bearing damage and rattles and clatters all the time. I asked Hoval for the price of a spare part. I'm curious to see what they come back with... For the next house construction, Hoval is definitely out...