Straight from the horses mouth.
Honeywell ones don't even require a key.
-Integrated radiator balancing insert.
How to optimise your combi boiler
- Thread starter dirtychinchilla
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Honeywell ones don't even require a key.
-Integrated radiator balancing insert.
Soldato
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If you watch the video, that's a highly specific tool, which almost certainly only applies to Drayton TRVs.
Most TRVs, especially mine, are unknown / generic / old and therefore require the lockshields to be used for balancing as per the following links:
Radiator Balancing: Step-By-Step Guide
Are some of the radiators in your home taking longer to heat up than others? Discover when and how to balance radiators in our useful step-by-step guide.
www.homeserve.com
How to Balance Radiators (and Why It Matters)
If your radiators are heating unevenly, you may need to balance them. Follow our step by step guide on balancing radiators to help fix this issue.
www.onlyradiators.co.uk
The Simple Guide to Balancing Radiators | UK Radiators
When it comes to balancing radiators you might not know where to start. Luckily, our simple guide to balancing radiators has all of the info.
ukradiators.com
How to balance radiators | BestHeating Advice Centre
Balancing radiators is easy. In this BestHeating Guide, we look at how to balance radiators to save money and ensure energy efficiency.
www.bestheating.com
How to balance your radiators with smart radiator valves | Hive Home
Are your radiators not heating up properly? Discover how to balance your radiators with the use of smart radiator valves with this step by step guide from Hive.
www.hivehome.com
Heat Geek Articles & Blogs | Heat Pump Guides, News & Advice UK
Explore expert-written heat pump articles, guides, and news from Heat Geek. Learn about low-carbon heating, grants, installs, and homeowner FAQs across the UK.
www.heatgeek.com
BUT, I'll grant you the caveat that if you have modern TRVs (and perhaps the tool for them!) then it is possible.
And if you reach my original post I said MODERN, then I also said Honeywell valves don't require a tool.If you watch the video, that's a highly specific tool, which almost certainly only applies to Drayton TRVs.
Most TRVs, especially mine, are unknown / generic / old and therefore require the lockshields to be used for balancing as per the following links:
Radiator Balancing: Step-By-Step Guide
Are some of the radiators in your home taking longer to heat up than others? Discover when and how to balance radiators in our useful step-by-step guide.www.homeserve.comHow to Balance Radiators (and Why It Matters)
If your radiators are heating unevenly, you may need to balance them. Follow our step by step guide on balancing radiators to help fix this issue.The Simple Guide to Balancing Radiators | UK Radiators
When it comes to balancing radiators you might not know where to start. Luckily, our simple guide to balancing radiators has all of the info.How to balance radiators | BestHeating Advice Centre
Balancing radiators is easy. In this BestHeating Guide, we look at how to balance radiators to save money and ensure energy efficiency.How to balance your radiators with smart radiator valves | Hive Home
Are your radiators not heating up properly? Discover how to balance your radiators with the use of smart radiator valves with this step by step guide from Hive.Heat Geek Articles & Blogs | Heat Pump Guides, News & Advice UK
Explore expert-written heat pump articles, guides, and news from Heat Geek. Learn about low-carbon heating, grants, installs, and homeowner FAQs across the UK.
BUT, I'll grant you the caveat that if you have modern TRVs (and perhaps the tool for them!) then it is possible.
So yeah of you have old valves then your stuck with the lockshield which as you have found gives a very narrow range of adjustment.
If you have a modern system as well balancing doesn't achieve anything you do more harm than good.
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Lockshields are ****. TRVs are ****.
There was a study done some years ago in Denmark which showed that relying on TRVs to manage your heating system does not work. The first thing you have to do is drop your flow temperature.
In the study, they increased the flow temperature from 50C to 70C. They expected that the TRVs would close and control the dT. It didn't. The dT reduced.
When they returned the system back to 50C (actually on weather comp), it took 3 days for the system to settle back down and manage temperatures as it was before the experiment.
The moral of the story is, don't rely on your TRVs to optimise your system. Minimise the flow temperature first, then go to balancing. Our general advice (as a seller of self-balancing TRVs) is to close the lockshield quite far to restrict the flow rate before you balance.
Soldato
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Agreed!
I'm operating with the following assumptions (on my system, which is a 2015 gas combi and mostly original radiators, TRVs and lockshields from when the house was built 1985):
- Low boiler output temperatures = more efficient BUT will heat the house more slowly. I'll run with 65'C this winter initially and see how the gas use / house warming fares. Will turn down if necessary.
- Return temps must be below 54'C (for condensation with gas) - the lower the better, but looking at the efficiency curve, less than ~40'C has diminishing returns.
- Lockshields have been adjusted on all rads to achieve approx. 70% return temps (e.g. 56'C in, 40'C out)
- TRVs have generally been left on max, except for a couple of less used rooms.
- Thermostat is in the warmest / most-used room (living / sitting room)
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How old are the heads on the TRVs? If they are old gas ones, they may have seized.
And what would you recommend on an Evohome setup?
Soldato
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For anyone thinking of trying to balance their radiators to make their boiler more efficient, here is what I did, how long it took and how much I estimate I'll be saving:
(NOTE - I realise not everyone will have access to some of these tools, but I had them anyway - I didn't buy them especially, except for two more DS18B20 temperature probes @ £4 each).
58 'C = 86% boiler efficiency
Return temps after:
38'C = 96% boiler efficiency
Annual bill before = £911 (October 2022 prices)
+ 70 watt pump = £34 (assuming 12 hours a day for 4 months) = £945
Annual bill after (theory) = 0.86/0.96 * 911 = £816
+ 50 watts pump = £24 = £840
Annual saving (theory)= £105
(NOTE - I realise not everyone will have access to some of these tools, but I had them anyway - I didn't buy them especially, except for two more DS18B20 temperature probes @ £4 each).
- Unlock all lockshields and TRVs
- Open all windows to keep the ambient reasonable (if doing this in winter, leave windows closed)
- Start central heating and leave for an hour to hit a reasonable tempterature (monitoring output and return temperatures on the pipes immediately in/out of the boiler with DS18B20 / Raspberry Pi Zero)
- Measure input and output temperature of each radiator (I did this using an iOS FLIR)
- Close lockshields down slightly and leave to settle for ~20 mins
- Find out that the lockshields are terrible and only the last ~ 1/2 turn has any effect!
- Repeat steps 4-5 until radiator output temps and boiler return temps are where you want them (roughly 70% input temp as output)
- This process took me 2.5 hours (including the 1 hour initial heating time) for 8 radiators in a small 3 bed detached.
- EDIT - Realised the pump was on the max setting (70 watts). Setting to lowest (50 watts) and making small adjustments to the TRVs has resolved and added, slightly, to the savings.
58 'C = 86% boiler efficiency
Return temps after:
38'C = 96% boiler efficiency
Annual bill before = £911 (October 2022 prices)
+ 70 watt pump = £34 (assuming 12 hours a day for 4 months) = £945
Annual bill after (theory) = 0.86/0.96 * 911 = £816
+ 50 watts pump = £24 = £840
Annual saving (theory)= £105
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Boiler came on this morning and while watching the graphs to check what it was doing thought how balancing just doesn't seem possible.
Flow was 29c and return 24c. That was with 2 zones on 1 went from 17.5 to 19c the other 18 to 19c. It was done in under 5 minutes.
I have a bypass radiator in the hall which is the only one turned down because it gets noisy with high flow rates, the rest are open fully and the thermostats do the opening and closing.
Flow was 29c and return 24c. That was with 2 zones on 1 went from 17.5 to 19c the other 18 to 19c. It was done in under 5 minutes.
I have a bypass radiator in the hall which is the only one turned down because it gets noisy with high flow rates, the rest are open fully and the thermostats do the opening and closing.
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Sorry, no idea. Not sure how that's any different from anything else. Are you referring to the TRVs specifically?
When you say bypass radiator above, what do you mean?
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even self-balancing TRV's seem a misnomer ?, it is not a dynamic balancing, just an easy calibrated preset for specific radiator type / heat-dissipation,
a modulating pump that maintains a constant pressure even if trv's have turned off some of the radiators seems essential for the system,
I'll have to inspect the parents new combi setup to see if they have that -
I guess the bypass radiator is a compromise if pump doesn't change flow
Automatic balancing TRVs - Are they worth it?
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You can get TRVs that do dynamic balancing. They each have a built in DPCV. Have a look at this. On these Pt40s, you set the design flow rate and it will automatically balance the radiator for you. They virtually eliminate the need for commissioning. As you say, they should be paired with a pump at constant pressure but variable volume. You're unlikely to have these specific valves unless you have a heat network.
I haven't watched his video, but these aren't your typical self balancing TRVs. I also have mixed feelings about him; it's hard to trump 50 years of Danish district heating technology.
Soldato
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Figured out why my rads were so hard to balance (possibly).
The pump has three settings and it's on the highest.
I'll whack it down to the lowest and re-do the balancing - I suspect our house is small enough that the lowest setting with the lockshields open more would be more suitable.
That would also save a tiny bit on electricity, as it'll be running at 50 watts instead of 70.
The pump has three settings and it's on the highest.
I'll whack it down to the lowest and re-do the balancing - I suspect our house is small enough that the lowest setting with the lockshields open more would be more suitable.
That would also save a tiny bit on electricity, as it'll be running at 50 watts instead of 70.
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Each radiator is a zone and can call for heat independently. So for balancing you never know which radiators will be on and by how much because it's changing constantly.
You could have all radiators on 100% or one on 5%.
Bypass radiator is one without any thermostat on so it's always on.
My pump has two settings 6m head or 7m head, I think it modulates as well.
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Cool just checking I understood. Bypasses are the enemy of well-operated systems!
Boiler doesn't like no bypass, it throws a wobbler if the return is hotter than the flow.
Not sure why it would reduce efficiency it's keeping my hall and landing warm.
Soldato
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Bypass would return very hot water, which assuming it's a condensing boiler, would reduce its efficiency by reducing / eliminating the energy captured by condensing.
Worst culprit in my system is the usual - the bathroom radiator / towel rail. It's only got 1/4 turn valves, so getting the flow down involves mm of turn!
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Because if the heat loss through that radiator is poor, it will send a high return temp back to the boiler.
It's not my department, but at work one of the primary causes of poorly running system in the UK are bypasses in the system. They are supposed to be eliminated in new designs.
You can't run a full Evohome system without a bypass.
You have conditions where all the rads can shut off but the boiler is still running.
I added a radiator bypass as that scrubs heat off enough to stop the boiler thinking there is a fault.
The auto bypass deals with pressure related tasks.
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It's a weird quirk that we have in the UK. They don't have it on the continent, maybe because I'm thinking of district heating schemes. I can see why you have it though.