Solid fuel stove boiler control/ heat charger/ loading valve schematic.

[ex tractor man]

Hi,
I will soon be installing a multi-fuel stove with back boiler (Woodwarm Fireview 9 with 8.82kw to water) in my living room, with the intention of heating my hot water indirectly and running some radiators. I have done some research on load valve systems and very much like the concept.
I have a schematic drawn by the stove manufacturer and wondered if anyone had any thoughts.
the schematic is at: uuuuuu.woodwarm.co.uk/Rugulus_TSV_02.pdf

The schematic looks good and has allowances for power failure.
The 2 things that concerned me were:
1. It looks to me that circulation pump failure could impede the back up gravity flow/thermosyphon circulation, Would that be the case? To allow for such a case could a LK Acaso Termobac/Thermobac valve be used to allow gravity flow instead of the "power failure bypass zone valve", number 3 on the schematic? As I believe this would, correctly fitted in a circuit, open in case of power failure or pump failure. To find the valve google LK 822 termobac
(I can't post hyperlinks!)

2. Should there be another normally open zone valve after the boiler flow is teed off into the cylinder coil? I was thinking that when the pump is running and the cylinder is up to temperature, the radiator/ heat leak circuit will open, but should the cylinder coil close to avoid boiling the contents?

I hope this all makes sense.
ex tractor man

 

[ecowarm]

Your schematic here does conform to current regulations, I strongly suggest if you are not competent you employ someone who is. See the Hetas site for details

 

[peteheat]

Doesn't look right to me, I agree with a controlled temperature return to boiler however you must be very very careful, a better solution would be an accumulator / buffer using a laddomat as that remains open in the event of power failure.

Looks better suited to a controlled fuel source like wood pellet that switches off in the event of power failure, like all solid fuel boilers allowance must be made for dissipation of the residual heat in the boiler.

 

[ex tractor man]

Thanks for the replies.
ecowarm - it is good to know that it would conform as drawn, I am in the process of getting quotes from hetas certified engineers So you don't think pump failure would be an issue?

peteheat - I looked into accumulator tanks/thermal stores, and in a property of my own I could justify the cost (National Trust rented farm Cottage! ).
The termobac valve would allow gravity circulation to dissipate residual heat after the pump had stopped (when the flue goes cold) or to allow gravity circulation in case of power failure.
I have done a quick sketch, the pump is still powered on by flue thermostat.

The circulator pump should push the 3 port backflow preventer open for normal operation, but in case of power or pump failure the flap in the valve should failsafe to gravity circulation. Or am I just re-inventing the laddomat! I would very much like to know your thoughts.
Regards
ex tractor man

 

[peteheat]

The system is designed to work with buffers / accumulators not direct feed systems, the manufacturer told me that they are the original designers of the Laddomat type system, that and a few other things suggest to me they are a reputable manufacturer.

Why a flue thermostat?

I rarely move away from manufacturers instructions / data sheets Link

 

[ecowarm]

IMHO it does conform, but would be down to the installers on site.