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Thread: Design fault with Honeywell HR92 ?

  1. #1
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    Default Design fault with Honeywell HR92 ?

    I have just found out to my cost (new HR92 needed) that if your radiator valve presents horizontally to the TRV, then if you have any sort of small leak from your radiator valve, any liquid travels straight into the HR92 housing and fries the electrics. Mine was a really small leak, (eggcup worth on the floor), but still enough to kill the HR92.

    I am having the valve modified to present to the TRV vertically as I don't want to keep buying new HR92's!

    Could Honeywell consider for future engineering plans please?

  2. #2
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    Quote Originally Posted by basiluk View Post
    I have just found out to my cost (new HR92 needed) that if your radiator valve presents horizontally to the TRV, then if you have any sort of small leak from your radiator valve, any liquid travels straight into the HR92 housing and fries the electrics. Mine was a really small leak, (eggcup worth on the floor), but still enough to kill the HR92.

    I am having the valve modified to present to the TRV vertically as I don't want to keep buying new HR92's!

    Could Honeywell consider for future engineering plans please?
    Thanks for drawing attention to this. All my HR92s are horizontal bar one. Thank goodness I have not had a leak!

  3. #3
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    I'm surprised to hear so many people have horizontally mounted HR92's in the UK ? Is horizontal mounting even a supported arrangement for the HR92 ?

    I'm not sure that I fault Honeywell on this one. Having disassembled one I think it would be considerably more difficult and expensive to design the HR92 to be fully water tight when lying horizontal, or upside down in an EU configuration for that matter... they're expensive enough as is. (Are any of the competing electronic TRV's water proof ? I doubt it...)

    If you're worried about it happening again you apparently don't have much confidence in the state of your valve bodies ??! In the 3+ years I've had Evohome I've not had so much as a drip from any valve body, either my old cheap'o ones or the Valencia's I swapped in last year.

    I would think that leaking valve bodies would be a sign of faulty installation, poor quality valve bodies, or they're just really old and need replacing due to worn out seals. In any case I'd be giving them all a good look over and replacing as necessary. While it might have "only been an eggcup full", they shouldn't be leaking at all. Small leak today, large leak tomorrow!

    I think it's a reasonable assumption to make that any electronic TRV is going to be damaged by leaking valve bodies.
    Last edited by DBMandrake; 22nd April 2019 at 12:35 PM.

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    ....and I always thought horizontal was the norm! Designed with that in mind so you can read them. We live and learn.

  5. #5
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    Quote Originally Posted by DBMandrake View Post
    I'm surprised to hear so many people have horizontally mounted HR92's in the UK ? Is horizontal mounting even a supported arrangement for the HR92 ?
    In the UK it is quite common to have horizontal TRV's.

    I am not asking for Honeywell to make them completely waterproof to IP65 or whatever, but if you look carefully inside the body of an HR92 you will see that any splash of water has a clear unobstructed path to the electronics. My valves are also not prone to leaks - 18 radiators and in 19 years only one leak. BUT, given that HR92's are used in a bathroom/wet room environments, then they should have some simple form of ridge or rubber washed to protect the electrics from normal bathroom splashes, let alone valve leaks.

    That was the only point I was trying to make, a very simple and cheap engineering change to save others time, money and frustration.

    Now if only we could get Honeywell to listen and act on user feedback?

  6. #6
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    Take one apart to see how it goes together and I think you'll change your mind about it being "a very simple and cheap engineering change".

    There are all kinds of butt seams with click latches where the casing comes together at odd angles that aren't water proof that would be impossible to waterproof without a completely new case design that was designed without so many joints and use of o-ring seals in mind. You also have a slot in the front for the ribbon cable for the screen that would need sealing, as well as the screen itself that would need internal o-rings. Even the shaft for the motor with the cog on it would need a tiny o-ring on the shaft since obviously the cog is exposed at the bottom but the motor and it's wiring would want to be in the waterproof section. The battery compartment would need a waterproof lid adding.

    Finally, if the unit was completely air/water tight there would be no way to have any airflow through the device to allow the internal temperature sensor to respond in a timely fashion. With a totally enclosed sensor the response time would be very poor as it would basically be measuring the inside temperature of the plastic case rather than of air flowing through the unit.

    I'm not saying it's impossible, but it would be a complete redesign of the unit and would almost certainly make it a lot more expensive. Honeywell have no doubt decided it's not worth it for the very rare cases where one might be subject to a leak.

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