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Prob is the magna3 eg dt controlled with all the kit ends up around £600
Discuss Real world testing example of Condensing Boiler in older home in the Central Heating Forum area at PlumbersForums.net
Just read in a UPS 2 8M pump replacement post that a Dab Evoplus & a Grundfoss Magna 3 are suggested, you might be interested from the point of view that the also do temperature control, might be worth a look?.
Prob is the magna3 eg dt controlled with all the kit ends up around £600
Thinking more about it, would be inclined to agree with you, anyway when you balance your system you can just throttle the valve again until you get a average return temp of say 40Cish? and see how the system performs. if it is OK, then far cheaper maybe just to install a thermostatic valve in the line?. if it doesn't work you can just open it fully.
If you can put up some instructions / wiring diagram will have a look later on
I’m guessing dt as it’s got flow and return temp sensors
Havn't read all the posts yet so basically is it monitoring the cycle times and then by means of a relay interrupting the switched live to the boiler?. If so, what determines the optimum cycle time?.
I guess it sort of learns how long things take to get upto temp and then uses that data to calculate an approximate best run time after
Upstairs feels warm / like normal operation. Rads were so hot before couldn't hold hand on them. Now can just about hold hand on them not scalding.How are the room temperatures?. based on cycle time the boiler output is 12.24kw with 14 cycles/hour.
Actually the upstairs radiators are scalding hot still Just tried a few of them again I forgot I was trying to get the 10c on the first one last night so it's throttled down a bit.
Your system, if it interrupts the switched live must mean that the circ pump is also stopped? and when the relay recloses, the circ pump will restart and then burner will fire up as required?
OK so pump keeps running "as normal" so if the cycle times are reduced, then this should mean that the boiler has to fire for longer during during the cycle which is good, but the rads still have to emit the exact same kw to maintain a constant room temperature but how is this achieved as the mean rad temperature has to fall when this happens?.. For example with boiler cycling your flow/return temps of 70.4/61.7C gives a mean rad temperature of 66.1C and if the heating demand is 13kw then the boiler will have a 50% firing duty, so fairly equal on/off times, this ratio will increase the longer the burner is prevented from firing so hard not to envisage the mean rad temperature not falling with reduced output/cooler rooms.
Where it can work pretty well IMO is where all the TRVs are throttled in, these would then open further and help maintain a constant mean temperature?.
Browsing through a few posts in Automated Home re Evohome, it certainly seems that it cycles the boiler by turning the boiler switched live on/off, the boiler still has a permanent live so will do a normal pump overrun (where installed, mostly on gas boilers) each time the boiler shuts down.
Not sure about your particular model but I think that the post purge is optional and maybe selectable on some models.
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