Advise Fitting new Combi Boiler

[Richini]

Good evening,

 

We're about to replace our 26 year old combi boiler and would really appreciate recommendations on the accessories which should be fitted with it. 

 

As well as a magnaclean, our plumber has recommended we should be looking to fit a limescale inhibitor and an arrestor to prevent any pressure spikes damaging the combi manifold. 

 

Having read a few posts I'm tempted by the cistermiser combinate to act as the limescale inhibitor. Can anyone approve or disapprove of this choice?

 

For the arrestor I'm not quite sure if a prv is sufficient or is a 4 litre expansion vessel the best idea, or both? We do have water hammer currently. 

 

Third question is regarding which thermostat. Was previously drawn to the tado but now not sure. Anyone have any wise suggestions here? 

 

Thanks.

[JohnMo]

4 minutes ago, Richini said:

cistermiser combinate

Or BWT combicare. Cheaper, I have been using for a couple of years no issue. Get them on Amazon next day delivery.

 

Depending on what boiler you have chosen, I would take a look at the manufacturer own controller thermostat. You should also make sure you can run weather compensation, and have the function in the controller to have load compensation. The weather compensation will give a flow temp to match heat required by outside temperature. The load compensation will compensate for any miss match in the running curve of the weather compensation.

 

Wouldn't touch so called smart boiler control with a barge pole. Unless it's from the boiler manufacturer.

[Richini]

Thanks for the reply. Interesting that you've had a good experience with the bwt combicare, I had read they tend to get blocked up with limescale. 

 

We'll be getting a Bosch greenstar 8000, if there's any recommendations for this setup that would be great. Local weather compensation would be great, as would a thermostat that is quite robust if the internet goes down. 

[JohnMo]

 

 

24 minutes ago, Richini said:

blocked up with limescale

Not experienced anything like that, but we only have a minor scaling issue really.

 

To get WC, you may need this control for the boiler, plus the outside sensor.

 

https://www.worcester-bosch.co.uk/products/boiler-controls/directory/greenstar-sense-ii-weather-compensation-control

 

You then have TRV's on the rads set a couple of degrees above the normal room temp you want. No need for internet thermostats. Boiler just to ticks over at lowest temp possible. You should get really good efficiency.

[TonyT]

1 hour ago, JohnMo said:

 

 

Not experienced anything like that, but we only have a minor scaling issue really.

 

To get WC, you may need this control for the boiler, plus the outside sensor.

 

https://www.worcester-bosch.co.uk/products/boiler-controls/directory/greenstar-sense-ii-weather-compensation-control

 

You then have TRV's on the rads set a couple of degrees above the normal room temp you want. No need for internet thermostats. Boiler just to ticks over at lowest temp possible. You should get really good efficiency.

I have the sense 2, man it’s complicated!!

 

it falls out with the domestic range so the standard WB engineers don’t know much about it, you need to speak to their technical dept.

 

 

Edited August 3, 2023 by TonyT

[Richini]

Tony T do you have to run an additional thermostat for the hot water system also? 

[TonyT]

No I have a combi, as unfortunately  no space for a cylinder. so it’s a 2 core cable to the sense 2 and a 2 core cable to the weather comp sensor. Straight from the boiler

[TonyT]

Oh and it’s not connected to Wi-Fi, etc no facility for this on the as sense2