Upstairs rads getting hot, downstairs not at all.

[justanotherguy]

I suggest you call in a heating engineer.

Well, quite - that was the very first sentence in my first post. But in London I’ve been burnt before by having no idea what’s needed and several call-outs with high minimum charges.

It would be good to have an idea at least of the parameters. Fortunately other folks here have been helpful on that front.

 

[Razor900]

Thanks for your help.

I had to look up how to check d codes - I press "i", then scroll through the d codes with +/-, then "I" again to show the value.

Here's what I get, if that's right:

D.0 is 27

D.2 is 20

There're 3 rads + towel rail upstairs, and 3 rads + tiny bathroom rad downstairs (so 6 to 8 depending how you count)
Label says ecoTEC plus 837 R1 and "GB 376/3-5" if that means anything

I have been able to get the downstairs going temporarily by completely turning off all upstairs rads, including the towel rail (which I'd forgotten), and all except one of the downstairs rads. Then it finally gets hot.

I then gradually turned on the other two downstairs, and they also got hot.

But the moment upstairs rads come on, the downstairs stops again - so I guess that points to a pump issue?

I do still see the the boiler cycling from burner on, going from 50 to 80C, then burner off, then radiator flashing symbol for 30 seconds (which I believe means burner off, pump on), then back to the start every 60 to 80 seconds.

I've tried fiddling with the heating flow temp, and have wacked it up to max of 75C for now (even though I know that's not efficient)

Like most eco techs it was never set up properly. It’s a boiler that starts up at 70% power then ramps up before it modulates down sending 27 kW into a system that can only take about 6 kW. Then the anti cycle won’t let it fire for 20 minutes.

Set D.0 to 10 and D.2 to 5 and see what difference it makes before you call anyone out.

 

[terryplumb]

Well, quite - that was the very first sentence in my first post. But in London I’ve been burnt before by having no idea what’s needed and several call-outs with high minimum charges.

It would be good to have an idea at least of the parameters. Fortunately other folks here have been helpful on that front.

Indeed , unfortunately there is a limit to what can be diagnosed remotely. You asked for " parameters",and if things could be "narrowed down" to lessen the chance of being " burnt".
The information given by all the contributers has hopefully given you some clarity in that regard, and I sincerely hope you engage a reputable engineer who Will sort out your issue competently at a reasonable cost. We do exist.

 

[dilalio]

Hmm, actually that's a good question. I assumed that, but now I'm remembering a few months ago I changed my Tado system to heat to a minimum of 16C in all the bedrooms 24/7, as I realised belatedly that was a cause of damp and probably didn't save that much money on heating (it's a 1950s house with solid walls)

So it's possible this never worked in colder weather before and I didn't notice, because I had the bedrooms off during the day, and downstairs off during the night.

Just to add, to remove Tado from the equation I removed them from the downstairs rads to ensure they weren't blocking flow - they weren't)

Check for sludge and balance the system.
You didn't mention you had smart TRVs.
Remove all these and balance the system but check for poor system water as well... Fairly easy... Shut off valves to smallest rad and drain and remove it.
Plenty of videos that show you how.

 

[dilalio]

We do exist.

 

[justanotherguy]

Like most eco techs it was never set up properly. It’s a boiler that starts up at 70% power then ramps up before it modulates down sending 27 kW into a system that can only take about 6 kW. Then the anti cycle won’t let it fire for 20 minutes.

Set D.0 to 10 and D.2 to 5 and see what difference it makes before you call anyone out.

Thanks!

Lowest D.0 goes to is 12, so I've set D.0=12 and D.2=5 - will post back how it goes

 

[dilalio]

Thanks!

Lowest D.0 goes to is 12, so I've set D.0=12 and D.2=5 - will post back how it goes

Many boilers are just thrown on the wall and not "range rated" or configured in other ways that suit the system...
And almost all combis are oversized for DHW performance, which is why CH modulation settings are so important... else boiler spends it's life cycling and rarely gets corrected.