combi boiler for summer / rayburn for winter?

rhjcat · Post by **rhjcat** » 29 Aug 2008, 21:38

Hi,
This may seem like a strange scheme but here goes ... Basically we have an oil fired central heating / dhw system at present run by a 10 yr old but reliable combiboiler. We want to move away from using oil as much as possible however, and so are thinking of installing a solid fuel rayburn that could supply c/h and dhw. HOWEVER. We summer let our home (and live ina shed!) and cannot rely on a rayburn for all the guests needs during the summer - they're not going to want to keep it fuelled up on hot days etc. Would it be possible to have the rayburn on for the winter months when we're in the house running a system with a hot water tank and then some kind of valve / switch to bypass the rayburn and tank in the summer and use the combi boiler instead? I know solar etc. linked in with a rayburn would be a simpler system and I know that it might not be a system to suit all but can anyone tell me if it's possible? I'd be so grateful as I'm not a plumber and am struggling hugely to work out whether the pipes for one system would also be OK for the other . Thanks so much, rhjcat

JohnB · Post by **JohnB** » 29 Aug 2008, 22:43

There's a system available that I can't think of the name of, that allows more than one boiler to be connected to the same system. It's a mechanical system that I've seen installed in houses with a log boiler added to an existing oil boiler. If the log boiler doesn't produce enough heat the oil boiler will start up to provide the extra. It was produced on a small scale by a small British business. I think it cost about £500 though.

rob · Post by **rob** » 29 Aug 2008, 22:45

The problem marrying the two together is that the combi is a pressurised sealed system and the Rayburn is open vented, tank gravity fed system. Combining the two would not work as putting the combi into open vent would see water gushing continuously out of your HW & CH storage tank overflows and putting a solid fuel vented system into a sealed system, with nowhere for any possible expansion to go (Rayburn/AGA's cannot be thermostatically controlled per se)... boom!

Putting valves on/or capping off your vents from the Rayburn hot water draw off or central heating expansion is just a serious accident waiting to happen.

Above advice £45.00 plus VAT
Rob the Plumber

RenewableCandy · Post by **RenewableCandy** » 31 Aug 2008, 18:41

JohnB wrote:There's a system available that I can't think of the name of, that allows more than one boiler to be connected to the same system. It's a mechanical system that I've seen installed in houses with a log boiler added to an existing oil boiler. If the log boiler doesn't produce enough heat the oil boiler will start up to provide the extra. It was produced on a small scale by a small British business. I think it cost about £500 though.

Would that be the Dunsley neutraliser?

JohnB · Post by **JohnB** » 31 Aug 2008, 19:21

RenewableCandy wrote: Would that be the Dunsley neutraliser?

No. It was a system with loads of pipes. It was made by a one man business who didn't publicise it much as he wouldn't have been able to keep up with demand. There was a web site, but I can't remember the name.

SunnyJim · Post by **SunnyJim** » 01 Sep 2008, 10:42

I have a solid fuel rayburn for winter and a gas boiler for summer use.

No problems.

tomhitchman · Post by **tomhitchman** » 01 Sep 2008, 11:34

JohnB, think this is what you are describing, I found it when an installer said that there are a number of problems with the Dunsley Neutraliser, this was designed as a replacement by another company.

www.h2panel.co.uk/

H2 Control System

Links a solid fuel boiler with an automatic boiler

H3 Control System

Solid fuel control system

H4 Control System

Links two solid fuel boilers together

tomhitchman · Post by **tomhitchman** » 01 Sep 2008, 11:46

update: just found my notes from talking to the h2 panel guy, not sure it solves all the issues though. The guy mentioned at the end of the note seemed pretty clued up on it all so might be worth giving him a call.

"the h2 panel is designed to manage a solid fuel and an automated boiler (gas, oil etc) to the extent that it will always prefer heat from the solid fuel source.

I spoke to the guy on the phone and here are the results

- the primary source is always considered to be the solid fuel device
- the solid fuel will need to be gravity fed with a heat sink radiator in case of a power cut.
- the solid fuel needs its own flow and return, separate from the gas boiler
- with solid fuel will need an open vented type
- did mention the 'albion mains flow' thermal store which is an open vented type
- normally a heat store thermal store would have a temperature of around 70 degress working temperature.

he has a customer who buys the h2 panels that also has experience of the dunsley wood burning stove. The company is Cliffords, his name is steven and is based in wisbeach in cambridgeshire phone no 01945 881 234. . mobile 07932 747 008"

SunnyJim · Post by **SunnyJim** » 01 Sep 2008, 19:30

If rhjcat return's I'll type up details of my set up, but right now I don't have the fingers for it....

rob · Post by **rob** » 01 Sep 2008, 21:54

Originally rhjcat just mentioned valving on/off his proposed double system. If he is in the realms of having quite a bit of money to spend then the system is feasible but beware! Adding something akin to a Dunsley Neutraliser will probably invalidate any guarantees your Rayburn boiler may have. Rayburn are quite specific that their boilers are for open vented systems only. There is on the www.ultimatehandyman.co.uk (DIY forum) a diagram of a solid fuel system with combi boiler, custom built thermal store and solar panel back up to boot. The respondents to the article are falling over themselves in congratulation but the plumbing looks a nightmare to me, just so much to go wrong.

JohnB · Post by **JohnB** » 01 Sep 2008, 22:21

tomhitchman wrote:JohnB, think this is what you are describing, I found it when an installer said that there are a number of problems with the Dunsley Neutraliser, this was designed as a replacement by another company.

www.h2panel.co.uk/

H2 Control System

Links a solid fuel boiler with an automatic boiler

That's the one. These are the boilers we were installing when I saw one
http://www.dunsterwoodfuels.co.uk/vigas.html