Which Drayton Auto-balancing TRV body?

[MilkTrayMan]

I have 10 Wiser TRVs. I want to replace the existing valve bodies with Drayton auto-balancing ones but am unsure whether I should use the TRV4 body (15 settings) or the EB body (6 settings).

What is the difference between the two? Is one is better suited to Wiser than the other?

The TRV4 body has a nice table that shows the correct setting for different radiator outputs but the EB has some complicated flow capacity graph that I can make head nor tail of. This is swaying me towards the TRV4 body but it's a fair bit more expensive.

[PhilHornby]

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@MilkTrayMan wrote:

I have 10 Wiser TRVs. I want to replace the existing valve bodies with Drayton auto-balancing ones but am unsure whether I should use the TRV4 body (15 settings) or the EB body (6 settings).

I think only Drayton/Schneider can answer that - and they don't currently participate on this forum. They do normally answer Support emails fairly quickly and I think (shock horror), you can simply ring them 🙂 )

@MilkTrayMan wrote:

What is the difference between the two? Is one is better suited to Wiser than the other?

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I had a glance at the Drayton web-site for the two valves - and it's as clear as mud. The commissioning guide for the TRV4 valve seems to refer to the EB and there's no such document on the EB page. Maybe one is replacing the other.

The Wiser iTRVs will neither know nor care which valve body is in use (mine are all Pegler). When calibrated they just close fully and open "a bit" when commanded to do so. This behaviour has changed over the years - they definitely used to open more, making more noise as they did so and chewing through batteries faster. (There is a suggestion of 'proportional opening' but I've seen no evidence of it and it would be a bügger to test (when you think through the details). Drayton/Schneider should know the answer., you could ask 'em when you call 🙂...)

Going back to the Drayton valve-bodies, I'm surprised to see olde-worlde instructions to set them for an 11°C drop. I've seen a video for a competitor brand, where you just use an App, telling it the radiator size and type and it tells you what to set the valve to.

Personally I have never succeeded in balancing radiators using the temperature drop method - because it is just not stable. Youtube is full of professionals telling you to use this method - but they don't actually demonstrate its successful use. (I tell a lie - one tried it in, in a lab-like teaching environment ... and failed!).

There are some more balancing-related ponderings, in this thread. 

(The automated forum-police apparently ban the word "bügger" - though not very effectively 😀)

[MilkTrayMan]

Thanks @PhilHornby 

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@PhilHornby wrote:

I think only Drayton/Schneider can answer that - and they don't currently participate on this forum. They do normally answer Support emails fairly quickly and I think (shock horror), you can simply ring them 🙂 )

I might drop them a line, see if they understand their own products.

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@PhilHornby wrote:

I had a glance at the Drayton web-site for the two valves - and it's as clear as mud. The commissioning guide for the TRV4 valve seems to refer to the EB and there's no such document on the EB page. Maybe one is replacing the other.

Glad I'm not the only one who found it confusing. Having looked into it some more since posting I think that the EB valve simply varies the size of the hole the water flows through so more pressure equals more flow where as the TRV4 valve is more sophisticated and maintains a constant flow regardless of pressure (assuming it works the same as the IMI Eclipse valve - there's a good demo of how that works on their website).

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@PhilHornby wrote:

I've seen a video for a competitor brand, where you just use an App, telling it the radiator size and type and it tells you what to set the valve to.

Drayton do have a setting calculator for the TRV4 on their website that's pretty easy to use.

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@PhilHornby wrote:

Personally I have never succeeded in balancing radiators using the temperature drop method - because it is just not stable. Youtube is full of professionals telling you to use this method - but they don't actually demonstrate its successful use. (I tell a lie - one tried it in, in a lab-like teaching environment ... and failed!).

Me neither. I'm hoping that being able to set an exact value on the flow will be more successful than the vague twisting of a lockshield valve on the return.

Having done a bit more research I think I'm going to use the IMI Eclipse valve. It's cheaper and there's a really good demo video on their website.

Bügger me. This forum doesn't make selective quoting easy 😂