Durnsley Heat Neutralizer - Opinions

[Rick]

Hi, I am thinking of getting a wood burning stove with a back boiler, in particular, the Durnsley Heat Yorkshire stove,

Now to connect it to the CH system they say that you need a Neutralizer

anybody have any experience of these? or know of an alternative?

Opinions?

P.S. as British Gas have just announced a 12.5% increase, a cheaper source of fuel seems more and more attractive

Rick... (The other Rick)

[chris 159]

my pa fitted one of these to a calor gas boiler and solid fuel back boiler years ago. he said it saved him loads of £,s

[Christian McArdle]

of a direct heat bank with no actual heat storage capacity. A heat bank is preferable, but a neutraliser will work just fine, provided you understand its limits.

Christian.

[Syke]

We fitted a woodburner with back boiler about ten years ago, to work in conjunction with an oil boiler. I seem to remember the alternatives were a Dunsley Neutraliser or motorised valves but the Neutraliser appealed as it had no moving parts to wear out. We now have the same oil boiler but with a wood stove with no back boiler as this suits our layout better now.

However, while we used the neutraliser it did seem to work effectively. If the woodstove was on as well as the oil boiler, the oil boiler didn't cycle nearly as often; it seemed to be a matter of balancing the various controls (pipestat etc) to suit your own usage, then just letting the system get on with it.

Pat Macguire

[Doctor Drivel]

If he has decent mains water pressure and flow, the heat bank/thermal store is the best way to go. The store of water provides a buffer for the boiler-to-store to prevent boiler cycling and a buffer-to-CH circuit to even out heat distribution. In Germany a heat buffer is becoming pretty standard on many installations, just a small cylinder in the CH line, the thermal store/heat bank does this for free, it also doe boiler buffering for free too. Here is one German system. They use a pressurised cylinder with fresh water in the boiler and through the heating circuit, which is not allowed in the UK, but look at the system as primary water and add an external plate heat exchanger for DHW take off and it is all there for the UK market.

"Compact systems with just one tank [thermal store] that also acts as buffer storage for the boiler dominate the German market. In conjunction with wood-burning boilers there remain no alternatives since such a buffer volume is urgently needed for their use. However, combination tanks with integrated gas or oil burners use a large storage tank to replace the boiler and its tank for heating domestic water [integrated thermal stores]."

The Germans are way ahead of us.

Taking the central heating off the store of water means TRVs can be fitted on all rads except the rad used as a heat dump rad for the solid fuel, which should be take directly off the thermal store/heat bank cylinder (can be the bathroom towel rail). A Grundfoss Alpha auto variable speed pump on the CH circuit is needed too - these are cheap enough.

Dunsleys are not cheap either. Just an empty short cylinder. Not worth it when so much, much, more can be gained with a thermal store/heat bank.

[Rick]

Many thanks for the reply's, You have put my mind at rest that I wont be buying an expensive white elephant.

Rick... (The other Rick)

[Syke]

Rick

I don't know what your time scale is, but when we changed our wood-stove a couple of years ago, the Neutraliser was just blanked off. We're making some more plumbing changes soon in connection with a loft conversion and the plumber is going to do his part in 2-3 weeks, at which time I intend to retain the Neutraliser. You might be interested in it but possible difficulty is that we live in Central Scotland and although it's basically a steel box, it's still quite heavy.

Anyway, just a thought

Pat Macguire

[Rick]

Thanks for the offer, but as I live in Cardiff it probably wouldn't be cost effective for me to collect it.

Rick... (The other Rick)