3 way motorised mixer valve for solid fuel rayburn?

[justing]

We installed a 355 solid fuel Rayburn a few years back. Recently getting advice to add a three way mixing valve so that a little hot water passes back into the cold return of back boiler, in order to maintain a constant 50ish degrees in boiler. Im told once the system is heated, it will be more efficient heating the 8 or so rads we have and give a better constant heating, as currently water is cool when it returns. Its a gravity fed dhw system with a thermostat and pump to switch over and heat rads when tank is up to temp.We burn good dry wood.
Any advice on what exactly is required, it will be fitted by a plumber, but not many round here are clear on what exactly is required or the best way to go about it...

 

[djsarge1973]

Sounds like a contradiction to me, a "blending valve" is used on domestic water i.e. baths, sinks & basins, to regulate the water temperature (this is now a current law on ALL new builds) So IF the rayburn is running 8 radiators, where would you fit it? as you have a Flow (going to the radiators) & a return (from the radiators) also how hot does the water in the rayburn get if its solid fuel surely you cant regulate that?? as Blending valves are VERY sensitive to over heated water (you could be constantly changing it) just use that old addage "if it aint broke dont fix it" you could be asking for more trouble than its worth!!!

 

[Norcon]

If its installed as per the MI's then it will be fine.
That usually means a gravity circuit to the HW cylinder which is self regulating with an injector T and hi-lo stats controlling the circulator.
I think your appliance has an integral low return stat fitted.

 

[justing]

@ Norcon, yup was fitted as per MI, yes it has integral low stat. Mates have started installing a make called Louberger(?) who insist on this kit fitted for safety, n when we discussed it just seemed like a no-brainer for us, as we desperatley need more heat in circulation of rads, n by maintaining higher temp in boiler sounded like we could have more constant output, more efficient burn??

 

[justing]

@ djsarge, water in rayburn gets as hot as installed stats allow it, depends on what stats are set at the out pipe, we just trying to make the burn more efficient and have more constant temp therefore more hot water circulating around the rads more often..??

 

[Norcon]

Mates have started installing a make called Louberger(?) who insist on this kit fitted for safety, n

I think you mean laddomat.
It will be an order of magnitude higher in cost and not necessary imo and completely safe using rayburns method and probably just as efficient.