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New to Evohome - only one radiator warming

Posted: Fri Dec 22, 2023 11:49 am
by mattie
Hi all

We've recently moved into a house and we've needed to rebind the evohome controller to two BRD91 relay boxes and a CS92 boiler thermostat box. We have no radiator controllers or any other devices, all radiators just have mechanical thermostatic valves, and hence we operate one zone only.

This was all working correctly when we moved in but we needed to shift some wiring so we've needed to reconnect and rebind.

All binds correctly in the guided configuration, however in use only one radiator becomes warm - this is a small radiator in the utility room near the boiler. The others become occasionally lukewarm. The hot water works OK. The evotouch correctly senses when central heating heat is needed and the wireless relay box correctly fires up, but only one radiator gets hot.

Some background to the plumbing, in case it is significant - a quick look at the pipework shows there are three pipes coming down from the boiler, at least from where I can see. The first pipe splits into 3, with two 2-way drayton zone valves on two of these splits and nothing on the third. The second pipe just goes straight down and out. The third pipe has the central heating fill and the magnetic filter - I'm not a plumber and there's no notes or other documentation to refer to so I don't know what each pipe or valve controls. This pipe with the magnetic fill is hot, the pipe on the zone valves are warm but not hot (the hot water tank is full and heated, so it's not requiring any heat at this time). My noddy assumption is that the split on the first pipe with no filter goes on a small loop to the single radiator to ensure there's always a circuit to heat, and one or both of the zone valves go to the rest of the house - and this/these are not opening.
(I can of course provide a phot if useful).

There are a jumble of other pipes in there, but those are the only ones I can see connected to the bottom of the boiler.

I'm not sure if I've set the controller settings correctly - I have selected '2 two port or 3 port vales' for the stored water and just a wireless relay box for the boiler control (it isn't opentherm), and I've selected zone valve for heating type under the zone configuration. We have one zone only, using the evotouch sensor as the temperature sensor.

Do I need to change any of this, or do anything else, to get the remain radiators to heat? Is there much harm in playing with settings, or am I just going to get into a jumble or (worse) damage something?

The system is quite old, I'd estimate around 15-20 years for the Worcester boiler, so it may just be the valves etc (and maybe the boiler itself) are starting to fail, but I'd rather make sure I've not made an obvious mistake in configuration before getting in the gasman to sort my mess out! The boiler is on the list for replacement this year anyway, and we're debating whether to retain to evohome (the internet account is under the previous owner's account which is another issue to sort!)

Any advice or guidance much appreciated

Re: New to Evohome - only one radiator warming

Posted: Fri Dec 22, 2023 5:08 pm
by mattie
Just for update:

Called out fitter as just couldn't crack it and we're getting close to Christmas with no heating. He noted that the BRD91s were incorrectly labelled (they had HW and CH written on them) - he identified the hot water and central heating valves and noted the relay marked CH was activating the Hot Water valve!

We re-bound (re-binded?) the relays in the correct order - the opposite to that written - and all appears to be working. I'd no idea what valve was what, and I'd never have thought to have tried binding the relays to the controller in what appeared to be the incorrect order. In hindsight, I suppose there's nothing to stop the relays being bound in any given order - i.e. the system itself wouldn't 'register an error, it just sends hot water down a pipe. It explains why we had sporadic heat in the main radiators, as they'd have come on as we used hot water during the time hot water is scheduled.

Very frustrating to have to pay £100 callout for an incorrect labelling, but glad everything seems to be functional and the kids won't be shivering on Christmas morning.

Re: New to Evohome - only one radiator warming

Posted: Sun Dec 24, 2023 11:50 am
by Richard
mattie wrote:Just for update:

Called out fitter as just couldn't crack it and we're getting close to Christmas with no heating. He noted that the BRD91s were incorrectly labelled (they had HW and CH written on them) - he identified the hot water and central heating valves and noted the relay marked CH was activating the Hot Water valve!

We re-bound (re-binded?) the relays in the correct order - the opposite to that written - and all appears to be working. I'd no idea what valve was what, and I'd never have thought to have tried binding the relays to the controller in what appeared to be the incorrect order. In hindsight, I suppose there's nothing to stop the relays being bound in any given order - i.e. the system itself wouldn't 'register an error, it just sends hot water down a pipe. It explains why we had sporadic heat in the main radiators, as they'd have come on as we used hot water during the time hot water is scheduled.

Very frustrating to have to pay £100 callout for an incorrect labelling, but glad everything seems to be functional and the kids won't be shivering on Christmas morning.
Good to hear things are fixed but frustrating is was something so simple. I've been on lots of call outs over the years and 80% of the time, it was a very simple fix.