Radiators heating up no call
Replaced Drayton LP822 and an old switch master wired thermostat.
Boiler is a British Gas 330.
I thought the heating was working in winter but now seems to warm up when the hot water is on (and seemingly other times). Tado saying it’s not the system asking for CH.
I have 2 zone valves that appear to work but not certain if they can be temperamental. It just seems odd the radiators heat with the hot water. So
I figure something is wrong with the wiring.
Tado said to choose wireless temperature sensor - despite the thermostat having been wired in. I wonder if I need to do anything here again.
My system is gravity fed - though there’s a pump for hot water for showers.
Any help would be appreciated to troubleshoot. Thanks!
Comments
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Are you sure you don’t have an S Plan system?
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@Zbrothm Hello. Three possible reasons
- Wireless receiver configuration. The BG 330 boiler documentation says it's fully-pumped, i.e. S-Plan or Y-Plan,
- A faulty or sticky zone valve.
- A wiring problem. Can you post pictures of the wiring, before and after?
EDIT:Typo.
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Ah ok. I had assumed it was gravity fed given the tanks sort!. Let me take some photos this weekend and provide update. Thank you!0
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There’s a lot of confusion about that. Given they have all but disappeared, I don’t know why Tado give that option.
They actually mean that it has no pump to circulate the water; hot water rises, cold falls - hence gravity circulates the water.
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Thank you! I think I may have an S plan from reading @wateroakley re: BG330 documentation and @Montage question, then more on a related link that sent me to DIYwiki, though I'm not certain. (I have found an old photo of the replaced Drayton LP822 that shows the 'P' selected, so another fact that makes me think so!).
I had assumed gravity fed given tanks and the fact I can only hear the pump running when hot water is chosen in one bathroom, I figured that was specific to that bathroom as the other shower has it's own pump. I do not hear it when the CH is going (perhaps that's normal sorry!).
Attached are a number of photos of the wiring and current setup.
Thanks for the help. If it is pumped (as it appears to be), do I go through the setup all over again and will that 'erase' the previous setup? I want to make sure I don't carry over any old info.
Thanks.
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Those black cables from the ‘wiring centre’ probably feed the zone valves. Get the Tado config changed from gravity fed setting to S Plan and you’ll be sorted. Tado will just save the new setting and overwrite.
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And there was an orange jumper in the extension kit. Do I need to move that? And is switching the thermostat to wireless an easy wiring change? Thanks!0
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Tried to do this via the non-pro app.
Both valves appeared to open correctly when called by the app earlier.
CH has just come on when hot water should.
Then downloaded the pro app to follow instructions.
Currently waiting for installer menu on the thermostat but v slow.
Have I missed anything?0 -
Update: CH still in with HW after choosing relay S-plan in pro app. Any advice is appreciated!0
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Sounds like you need to work through what’s happening. The zone valves are both in one of your shots, pump and wiring. That’s not the central heat8ng pump.
There’s usually a manual lever on the zone valves and it can help with checking if they are open or closed. Test HW alone and then CH alone and establish what happens. Start with making sure both are shut before testing.
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Thanks! Ok I have attached a photo of what I think is the correct pump here. A BritishGas Grundfoss with power to it before the zone valves.
There are 3 pipes after that 2 to zone valves and 1 to a Taconova Ratesetter (not entirely sure what that is).
When I call for hot water, the zone valve to the middle of the cylinder opens properly (this is the only destination for the pipe run). At the same time, the RateSetter pipes heats up as like there's nothing preventing the water going. This goes to the bottom of the cyclinder and into the floorboards. This then heats up the radiators.
When I call for heating, the other zone valve opens, these pipes tee off into the bottom of the cylinder and under the floorboards, and certain radiators heat up (on set of lounge radiators does not heat up while the HW is called, the other heats up while the CH is called). These pipes are all down from the ceiling in an older home.
Lastly, the bathroom towel rail has no valves so I understand is a bypass radiator (located adjacent to the airing cupboard).
Perhaps I've misunderstood the 'plan' / layout - and without lifting the floorboards it seems hard to know where the pipes run (upstairs not planning to lift carpet anytime soon, and I don't know if it's meant to work like this. Short of turning off the radiators manually at the valves it seems like it will be hard to prevent them heating up. Hopefully I'm missing something! Thanks again for the help so far!
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Those photos and the description help. You can see the two zone valves and that device in the middle is a bypass.
The idea of a bypass is to allow the boiler to shed some heat and/or to stop the pump dead heading when all the radiators have shut their TRVs. You seem to have established that certain rads get fed by that bypass circuit.
It appears to be an automated bypass, so it should only let so much water through. This assumes that it’s correctly set and it’s working properly. Either setting of the function loss could lead to more flow than you need.
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Brilliant, thank you. It seems I need to have a look at that and see how much water should get through. Is there a way I can look at what setting this should be / how much water should get through?
Most of the radiators on that circuit are old and do not have TRVs installed so I don't know if that was an oversight by the installer or not, but imagine it's been added onto several times over the years! Thanks again.
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There was a time when TRVs didn’t get fitted. As long as the rooms don’t overheat, I wouldn’t.
The bypass. There are two views. Firstly, many basic gate valves get fitted, shut fully then backed off a turn or so. No real problems ensue. By the book method, check the power output of your boiler and see if it’s been range rated to a lower amount. Check that against the graph and find it needs 10-15 litres a minute (probably).
I doubt you need to pay much attention, but try not to have it steal too much of the circulating water when you are trying to heat up the cylinder. Particularly important if it’s heating some rads (not a bypass requirement) as it’s wasted heat. Listen to the pump and for when the zone valves shut in case it creates noise. Then open up a bit.
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Gotcha thank you. So the rooms that heat up in the summer, is turning off those rads ok? Or does that defeat the purpose of that run?
I’ll also look into the official method and maybe stick to the full then back off a turn.
Thank you very much for your help!0 -
The bypass is normally designed to take the water back to the boiler, via the return pipe, so doesn’t require rads. Without tracing the plumbing, it’s hard to say. I’d certainly say it’s safe enough to try shutting them down.
Start with one and see if shutting one stops the flow through just one, or more rads. It’ll help indicate how they are piped. It’s a bit of an unknown, especially if the original system got extended.
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Thanks. Wasnt planning on lifting the carpets for a while. Turning off the hall rad stopped flow to the other rads on the bypass line.
Appreciate the help, guess ill leave it until we do more work / winter and turn them back on.1 -
Ok. Sounds like progress. Might be worth seeing if you can get your hands on an IR camera to get more clues. At least you have a lot more understanding of what you are dealing with now.
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