Flow Smart Overheating at low RPM and High Power

I've had my Flow for a few months now and its generally been fine

However as I've start riding a few more of the hilly Zwift sections I've had on a number of occasions the unit drop all resistance and data.

Cadence is around 68-70rpm and power around 280w

Looking at the Tacx Diagnostic iOS App, its telling me its a temperature issue

Any way to resolve this? 

  • Hello,  I do have the same issue with my Flow Smart, once,  but I used a fan next to it.

  • I also have this issue. I've used the trainer to successfully get in pretty decent shape and recently while racing, have pulled some pretty good power up the Road to Sky course as well as Leith Hill.  Problem is, now that I'm pulling 350W at 70RPM uphill it just can't take it. On the race I did today (last stage of Tour for All) heading up Keith Hill the Flow quit 10 times in the last mile and a half.  By the time I finished the trainer was very hot and couldn't hold power for more than 10 seconds before shutting down.  And I run a large box fan in my trainer space so there's a decent amount of air moving around.

    EDIT - after a few tries I finally got someone good from Garmin support via chat (Kevin) - he confirmed that this is a known issue and that the Flow cannot really handle loads over 250W at low RPM. That's bad news for me. He even linked me to an official response from Garmin - https://support.garmin.com/en-US/?faq=cfURSKfTWz9HTQt37XW8H7&productID=690890&searchQuery=LED&tab=topics. I'm in a holding pattern until Tuesday (long weekend) before I hear what Garmin's proposed solution to the problem may be. I'm hoping it will at least be a 100% credit of the purchase towards something that won't shut off under what is ~30% of the stated power handling capability.

  • Thanks for the update. That official response should be a warning in the manual - as I would have returned my unit, if this is a know issue.

  • I'd suggesting contacting customer support if you have proof of purchase and have owned it less than a year. It should be under warranty and agree, it's not performing/functioning as it should.

  • It's a shame I've only just found this page ;( but it's good news...

    For 18 months I've been trying to sort this problem. Just like you all, I’ve been experiencing bluetooth/power/resistance dropouts mid races/workouts. It normally happens when climbing or in longer races mostly. Lots of other people seem to be posting the same issue, and the discussion has centred on ANT/Bluetooth overload/proximity etc. I’ve tried all of the potential fixes over the past 18 months, but still get intermittent issues. It can go numerous times in one session and I have to wait, re-pair and hope it doesn’t happen again… before having to ditch the session in frustration. And sometimes happens, 30 metres from the finish line on a AdZ KOM race, much to the delight of fellow racers.

    This week, halfway up Alpe Du Zwift, it happened BUT after re-pairing several times, and spitting a few swear words, a thought occurred - could the turbo unit itself be overheating? (I know I was.) I trained a fan on it - and didn’t get the problem again Thumbsup All this time thinking it was a more technical issue. The trainer seems fine now (and cool) with a fan on it, with averages 300-350w / 65-70rpm up the Alpe.

    So just posting on here because of the sheer joy of sorting it. Happy Zwifting everyone.

  • As several people has stated he best solution for this is to point a small fan to the trainer itself. The part of doing high cadence when the power output is also high is just nonses... Like they want everyone be like froome to avoid overheating the unit...

    I´m doing the fan part and is working great, but sometimes I forget to turn it on and find myself frustrated when my power drops to 0 and the pack leave me behind... Because of this I'm using this design https://www.thingiverse.com/thing:3047910 (not mine but) and also doing a little twiking on the inside so the fan turns itself on once the trainer is conected.

  • OK just come across this thread after weeks and weeks of new cables Ant+ receivers etc after thinking it was interference or Zwift related. 

    Whilst i absolutely applaud and thank the OP for making us all aware here of the issue, im really pissed off Garmin has not mentioned this o released a fix. As far as i am concerned the device is not fit for purpose. I could easily add a fan myself and impressed to see someone has designed a 3d printable manifold to attache a PC cooling fan, but that's not the point. I paid hard earnt money for this device and wasted hours n hours training and wheel spinning waiting for the device to pick up cadence again, only to find it's a known issue by Garmin.

    Before i take this further i shall ping Garmin myself to see how they intend to resolve this for me and many others on here. Totally unacceptable.

  • Same here and thanks for sharing too i also had months of frustrations with this unit it's not acceptable though for Garmin just to shrug their shoulders, a fix should be issued or a replacement supplied we've all paid for a unit to help us train under high workloads. To subsequently find out the designed unit has a serious design flaw then it should be rectified by the product manufacturer.  

  • Be interested to see how you are adding this feature if you could ping me? However GARMIN should be releasing a fix for this where we send our unit in to be modified as it's clearly not fit for purpose at the moment.

  • Just to update i have spoken to Garmin support about this issue. 

    They have advised Tacx are aware this is a problem but are not taking any action to resolve. 

    Garmin support advised me they are aware of this issue also and supplied the following link


    "While in ERG mode if you are training above 250 watts for a prolonged period of time the trainer may go into an overheating protection mode.  If this happens the resistance on the trainer may cease while the trainer cools down.  In order to avoid this issue we suggest that you increase your speed during your workout.  Doing this allows the brake to decrease the resistance amount for your workout and in turn allows the trainer to operate at a cooler temperature."

    I can't speak for others on here but mine is failing whilst using SST training on Zwift in blocks of 5minute climbs which are peaking at 250w i am by no means a fit rider and it is still failing after the first or second stint. I would hardly call that a prolonged period! 

    So for the moment i stand by the fact this product is not fit for purpose. 

    I shall run some tests riding in a lower gear which should in turn make the rear wheel faster driving more air through the trainer. I am normally running about 6th gear on rear with largest ring at the front. Welcome anyone's feedback on their settings.