Real world testing example of Condensing Boiler in older home

[ShaunCorbs]

Prob is the magna3 eg dt controlled with all the kit ends up around £600

 

[JC22024]

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

I must read up on those but again I think my house suits a single speed pump.

Aka imagine some of the TRV valves start to close around the house. A smart pump would sense this and reduce the pressure or if it senses heat and modulates flow based on that then it would also throttle back the flow. And thus other radiators may fall dead again even when calling for heat.

It would work well no doubt in a new installation where the pipes and rads etc are properly designed installations but retrofitting into an old and somewhat unknown system / sizing probably won't give desired results IMO

 

[John.g]

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.

 

[JC22024]

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.

Yes I'll balance it properly first and see where the temps are at then.

Then run when I can monitor run time and burn time for a few days. Then downsize nozzle and repeat for comparison.

Then add the boiler energy manager and see if that reduces cycling etc. If it does then I'll probably leave it set up like that.

The BEM company can't give good advice on the wiring FFS! Asked a few times and the emails back don't make sense. They appear confused if it should link before or after my boiler stat. So I'll probably have to test that too and see which setup works best.

 

[ShaunCorbs]

If you can put up some instructions / wiring diagram will have a look later on

 

[JC22024]

If you can put up some instructions / wiring diagram will have a look later on

Thanks for that, I attach the PDF manual and also an extract of the wiring diagram below:

I have a CH wiring centre in my boiler room so no worries there. I understand their diagram also. But when I was simply asking that when installed on an oil boiler might it be best to link in before the boiler stat per diagram or go in between the stat and burner. Their reply was:

sorry for the delay responding, the black/grey cbles of the energy minder would smply wire in series with one of the cables from the boiler stat or their shoud be a link on the control panel for an external control wich would be removed and the black/grey cables wired into their place.

which doesn't help at all really they didn't understand what I was asking. I sent wiring diagram and photos of my boiler also. Anyway I'll follow their diagram and link thier black wires in between my "call live" wire from 240v zone valves switches and the boiler stat.

 

[JC22024]

I was just thinking that if the logic in the board of the BEM would function better before or after the boiler stat.

If it goes before the stat then there will be instances where it will be calling for heat and the boiler stat is satisfied. Burner not firing.

If it goes between burner and boiler stat then only when the burner demand is being called by heating system and boiler stat will it get signal and be able to control without the boiler stat interfering.

Personally I think the later may be the better setup- what do you guys think? Not knowing the logic of the device fully means however I should prob follow their diagram all the same!

 

[JC22024]

Not to confused things but I also did receive the Vector works BEM also. No instructions available for this one its top secret jobbie

On opening it, the connections are labeled. And it only has a power in, stat and boiler connections. No temperature monitoring aparantly. Not that I am qualified to comment but that hasn't stopped me before- appears limited for the high cost.

 

[JC22024]

Since the connections on the Vector unit were so simple I went ahead and wired it in temporarily at least. Boiler stat outlet going to "Stat" on its board. Burner wires connected to "boiler" on the board. Perm power added to remaining connection.

It appears to be working now. Upper figure is the call time of the boiler. Lower counter is the actual time it is firing the boiler.

So let's see if the house heats as well and the timers show a saving

 

[John.g]

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?.

 

[ShaunCorbs]

I’m guessing dt as it’s got flow and return temp sensors

 

[John.g]

Very good, a bit of a challenge maybe though to determine the optimum cycling time as the dT through a oil fired boiler (non modulating) is never the same as the rad deltaT except the boiler is underrated., but lets see.

 

[JC22024]

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 think I have confused this sorry guys.

Yes Shaun the dt sensors you seen are on the domestic BEM I purchased.

However I had also purchased one of these

Energy Management Solutions | Vector Group

£30 brand new on ebay. Aparantly only fitted by them and at a cost of about £2k. So I wasn't sure what it would need or how it was wired since they provide no instructions.

So when I discovered the simple labeled connections after it arrived this evening I temporarily wired it in.

John's understanding is correct. But this vector unit does not measure pipe temperatures.

I think it waits for the boiler stat to first become satisfied on cold start. Then has some sort of programme to monitor the cycles thereafter and decide how to eliminate boiler cycling.

Haven't been watching it but had a glance earlier and it's gauges appear to be registering it is reducing burner time VS demand

 

[ShaunCorbs]

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

 

[JC22024]

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

I thought it would have sensors of some sort or connections for them but no. I find that slightly odd but they must have a programme that doesn't require that to do it's job. It makes sense though that it goes between boiler stat and burner. I think the other one should be wired the same way on any oil burner.

I will compare this one and the domestic one with dt sensors just to see do they save much run time and what they actually do to the on / off times and flow temps.

This is a good link on boiler cycling and why it's bad FWIW (you prob already know this but I found it interesting for the most part)

https://www.wcrouse.com/stop-wasting-money-reduce-boiler-cycling/