Worcester Bosch Boiler Heating Controls

Valo · 23 Nov 2016 at 20:00

I've got a Worcester 38Cdi condensing boiler and need a bit of advice from any other owners as to the recommended setting for the Central Heating and Hot Water Temperature controls on the actual boiler.

My current settings on the boiler are 4 for Central Heating Temperature and 'e' for Hot Water Temperature. My Hot Water Temperature is absolutely fine. However I'm wondering if the Central Heating Temperature needs to be put to 5 or 6 to improve the efficiency and heating times of the system over winter?
The manual doesn't make it clear just to set it to your desired Central Heating Temperature and for effective management of the system to use a thermostat.

All of my radiators have Danfoss TRV's (most set to 3) and the system is run by a Nest V2 thermostat.

Any help or advice would be great.

robj20 · 23 Nov 2016 at 20:39

To be efficient set it so the return temp is around 55c or lower. Think the actual temp is 57c for condensing to take place.

Turning the temp up will decrease efficiency.

Valo · 23 Nov 2016 at 21:30

robj20 said:
To be efficient set it so the return temp is around 55c or lower. Think the actual temp is 57c for condensing to take place.

Turning the temp up will decrease efficiency.

Thanks.

Stupid question time....How do I know what the return temp is? Is that displayed on the small display screen on the boiler when an adjustment is made to the Central Heating Temperature Control?

robj20 · 24 Nov 2016 at 06:02

There should be a screen that shows the return temp. Better controls would do all this automatically. Weather compensation or better still Opentherm, but not sure worcester support Opentherm.

Failing that get a thermometer on the return pipe.

dirtychinchilla · 24 Nov 2016 at 14:00

Glad to see some good advice and some good kit on here. We sell those Danfoss TRVs

FlyingFish · 27 Nov 2016 at 10:26

The 38cdi as far as I know doesnt really have any user interface to show you the return temp. And in all honesty as a home owner you dont really need to worry about stuff like that. Your boiler will run very efficiently itself, and can modulate the pump to best maintain flow and return efficiency. No.4 is perfectly fine for the setting on the CH dial.

Your doing the right thing by using the trv's and setting a temp for each space. And the Nest will allow you to program temperature periods to your needs. Just dont make the temperature differences too big. The idea behind a programmable stats is not to allow the house to go cold, so you dont need to munch lots of gas getting it back warm again when your in.

If you want better/more efficient running of your boiler then your going to have to ditch the Nest, and ugrade to a WB Wave controller. This is hard wired to your boiler and wifi'd to your internet. It allows you to program temperatures in your house and also app driven (like the nest), BUT it gives you weather compensation that can directly ADJUST how the boiler operates, which NO other (non WB) control can do as the wave is connected directly to the comms of the boiler control board to alter its running.

Another upgrade would be to have a setup like Honeywell Evohome, that allows you to program temperatures in each and every room, but that setup isnt cheap. It has a base unit and also an app. And installation is minimal. We fit quite a lot of them

Mick

Valo · 27 Nov 2016 at 20:41

FlyingFish said:
The 38cdi as far as I know doesnt really have any user interface to show you the return temp. And in all honesty as a home owner you dont really need to worry about stuff like that. Your boiler will run very efficiently itself, and can modulate the pump to best maintain flow and return efficiency. No.4 is perfectly fine for the setting on the CH dial.

Your doing the right thing by using the trv's and setting a temp for each space. And the Nest will allow you to program temperature periods to your needs. Just dont make the temperature differences too big. The idea behind a programmable stats is not to allow the house to go cold, so you dont need to munch lots of gas getting it back warm again when your in.

If you want better/more efficient running of your boiler then your going to have to ditch the Nest, and ugrade to a WB Wave controller. This is hard wired to your boiler and wifi'd to your internet. It allows you to program temperatures in your house and also app driven (like the nest), BUT it gives you weather compensation that can directly ADJUST how the boiler operates, which NO other (non WB) control can do as the wave is connected directly to the comms of the boiler control board to alter its running.

Another upgrade would be to have a setup like Honeywell Evohome, that allows you to program temperatures in each and every room, but that setup isnt cheap. It has a base unit and also an app. And installation is minimal. We fit quite a lot of them

Mick

Thanks for the good advice Mick, it's much appreciated.

I had a bit of a search to see about adding Weather Compensation to my boiler but soon realised it wasn't possible with the Nest. I did discover the WB Wave as well while searching and it looks like an interesting option, however I'm happy with the flexibility the Nest offers coupled with the TRV's. I'm also invested in the Nest ecosystem with a few Protect alarms as well.

Since I actually turned the CH temperature up I think I've actually found the sweet spot for my heating. My Nest is recording an actual drop in the amount of heating I'm using, and the overall temperature in the house is staying warmer for longer.

Participant · 27 Nov 2016 at 22:20

I've found the Worcester Wave controls flaky, unreliable, hard to use, fussy, and poorly supported by Bosch themselves.

I mean when it works it works, but the bugs are infuriating, from crashing, to thinking nobody's at home when they are, to constant 'check your home presence temperature' notification messages, that the fool on the WB line didn't seem to know anything about.

On the plus side, it is efficient in the way it controls the boiler and in my opinion looks pretty cool on the wall. It also has DHW and CH control, which is handy (though I think they can all do this now).