New boiler and controls

[Paul-c]

Hello guy's
Could you please advise.
I am changing my old combi for a Worcester 440 CDi to get the hot water flow rate for two bathrooms.
At the moment there is one heating circuit in the house.
I intend altering this to two circuits (ground floor & first floor) but I am reluctant to run cables to hard wire two programmers for the circuit controls.
Can I "wireles" control the programmers? and if so what is the best controls to obtain?
How is the DHW controlled?
Thanks for any advise
Paul-C

 

[Simon F]

welcome along Paul.
first do you have enough flow/pressure at your supply?
do you need two programmers? is the floor area over 150m2? or do you just need two room stats
you can fit two wireless stats. but do you not already have one fitted hard wired?

ps:- the water is controlled by opening a tap, the combi boiler does the rest.

 

[Paul-c]

welcome along Paul.<br>
first do you have enough flow/pressure at your supply?<br>
do you need two programmers? is the floor area over 150m2? or do you just need two room stats<br>
you can fit two wireless stats. but do you not already have one fitted hard wired?<br>
<br>
ps:- the water is controlled by opening a tap, the combi boiler does the rest.

<br><br>Thanks for your reply Simon,<br>With regards to flow and pressure I don't think there is any problems The existing combi (Brittainy) delivered DHW to the two bathrooms but with a low flow rate and also the room rads were undersized so all the heating system is being upgraded<br>The reason for the two programmers was to be able to independently control the two circuits with time as well as temp.<br>The total floor area is about 150m2<br>The existing thermostat was sited at the bottom of the open stairwell (useless)<br>The original plan was to site one programmer in the lounge (ground floor) and the other in the master bedroom (first floor) but if this is a problem then plan B would have to be thermostats in the two rooms mentioned<br>Any further thoughts appreciated<br>Paul<br>
<br>

 

[doitmyself]

The existing combi (Brittainy) delivered DHW to the two bathrooms but with a low flow rate

Putting in a bigger combi will not give you a better flow rate, just hotter water. The flow rate from the combi is dependent on the incoming flow rate of the cold main, which has to be shared between all outlets, including toilets, washing machines etc etc. If you have 10 litres/min coming in and you want to run two showers at the same time, the best you can expect from each shower is five litres/min.

Measure your incoming flow rate, preferably at the garden tap, using a marked bucket and a watch.

 

[Paul-c]

Thanks for the comments doitmyself, the flow and pressure to the house is adequate (4 bar pressure and 20 ltr/min)
What I men't was that the throughput of the old boiler was not adequate enough (one bathroom and one shower room)
Back to your comment Simon, the "wireless thermostats" you mentioned are these time controlled stats? as the only reason for the programmers would be to control the on/off time
If so who are the manufacturers?
Thanks again
Paul

 

[Ermintrude]

You could try combi with a thermal store attached. Valiant would be my choice

 

[lame plumber]

You could try combi with a thermal store attached. Valiant would be my choice

whats the advantage of mixing a combi and thermal store?

 

[R1CKY]

Putting in a bigger combi will not give you a better flow rate, just hotter water. The flow rate from the combi is dependent on the incoming flow rate of the cold main, which has to be shared between all outlets, including toilets, washing machines etc etc. If you have 10 litres/min coming in and you want to run two showers at the same time, the best you can expect from each shower is five litres/min.

Measure your incoming flow rate, preferably at the garden tap, using a marked bucket and a watch.

Not entirely correct. Combis have flow restrictors built into them, you could have 25 l/min on the cold main and a restricted 10 l/min through the combi, a more powerful combi will have a higher flow rate.

I think the 440CDI is either a pre-store/thermal store type combi, so should have pretty good hot water performance. You'll probably find you can time the preheat function using one of Worcesters integral timers.

A set of wireless programmable room stats linked to two zone valves should make a good job of zoning. I highly recommend the Honeywell CM927 if you go down that route.

 

[AWheating]

most wireless programmable stats will do tbh, what does your installer recommend? sometimes better to go with what the installer is comfortable fitting.

 

[Ermintrude]

whats the advantage of mixing a combi and thermal store?

You get best of both worlds! On demand without keeping 210l at 75c

Just like old alpha Cd50 And wb floor stander 440? Big heavy steel tank in its

 

[dancinplumba]

Wonderful.... life is truly wonderful '

 

[dancinplumba]

All of them very poorly insulated tho

 

[Ermintrude]

What valiant cylinder? Poorly insulated?

 

[Paul-c]

Thanks for the responses I have been delayed in replying due to broadband connection problems
Ricky, I am inclined to go for the Honeywell wireless programmable thermostats & receivers controlling the Zone valves but what is the wiring plan to use? "S plan?
Also thinking of the wiring connection to the 440 CDi boiler, with it being a combi is there any issues?
Thanks
Paul C

 

[R1CKY]

The only thing to be mindful of on most Worcesters is, the power for any external controls must be taken from the PCB, not power supply feeding the boiler.

If you want, I'll knock up a wiring diagram for you?

 

[Paul-c]

Ricky, I think the wiring is resolved,(I have tried to attach a diagram to this post but failed, I will have to find out how to do it as it makes life easier)
Basically I see the boiler LS supplying the zone gray and receiver L
The zone brown to receiver B
The receiver, Link LL removed and LA linked
Neutrals and earth wires appropriately connected
The two zones are wired the same
How does that sound?
Thanks

 

[R1CKY]

Seems ok, the only thing you'll need to do is link "L" to "A" in the receivers. Assuming its the Honeywell stat.

 

[Paul-c]

Ricky, it is a Honeywell receiver and on my original drg. I had linked `L' to `A'
Thanks
Paul

 

[R1CKY]

Seems like you've got it sussed!