Gravity Check Valve (plus some Solid Fuel Heating questions)

swishy6

swishy6

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Hi, I'm trying to get my head around what's required to install a semi pumped system with a Rayburn Royal. I'm likely going to fit a high output boiler into it for a start, in case someone pipes up with "forget it" :rolleyes: I've got a garage full of logs and some, plus a Rayburn in there.

Anyway I'm studying this diagram and trying to be sure of how a gravity check valve works. The pipes from boiler to/from the cylinder I understand they're 28mm. I take it the pipework for the two heating legs ought to be 22mm with 15mm teeing off to radiators and a 22mm check valve must obviously be for water to flow in the direction towards the radiators.

How does it work though? Is it simply that the pump creates the necessary 'draw'(what would that be properly called) required for the valve port to open, while gravity alone would not have sufficient pressure to push the spring loaded device and allow water to pass? I can understand a zone valve better, along with the pump being controlled by stats.

Is a gravity check valve something unique or simply a bog standard single check valve? Clearly it's the cheaper option from a zone valve.
 
I had a rayburn.
You will spend all your time putting wood into it rather than with your feet up watching the tv.
Threw that out and got a nice lpg range cooker and the stupid government were daft enough to buy me a biomass pellet boiler.
If you wanted to use the wood I would go for a thermal store. You can then feed this with a number of different sources of heat.
I would use a zone valves to stop circulation unless the rayburn is hot. You will need a heat leak radiator regardless. Pumping is much better than gravity and unless you have a large coil tank gravity circulation won't work in a modern hot water tank.
 
Its usually better to have a device which prevents any circulation until the stove is somewhat hot as this prevents condensation and rusting.

But controls should be fail safe, meaning spring opening and powered to close so if power fails it does not overheat.

I got slightly wet a couple of weeks ago. I could not believe a 30 year old gravity check valve would not be leaking a bit. But when I cut the pipe above it there was still quite a lot of water in it although I had drained the pipe underneath about 30 min before!
 
A schoolboy error. You should have stuck something up it or removed drain screw.
 
dcawkwell said:
I had a rayburn.
You will spend all your time putting wood into it rather than with your feet up watching the tv.
Threw that out and got a nice lpg range cooker and the stupid government were daft enough to buy me a biomass pellet boiler.
If you wanted to use the wood I would go for a thermal store. You can then feed this with a number of different sources of heat.
I would use a zone valves to stop circulation unless the rayburn is hot. You will need a heat leak radiator regardless. Pumping is much better than gravity and unless you have a large coil tank gravity circulation won't work in a modern hot water tank.
Click to expand...

I agree here, get a thermal store, get the rayburn, get a free pellet boiler Its ideal and exactly what I did.
 
dcawkwell said:
I had a rayburn.
You will spend all your time putting wood into it rather than with your feet up watching the tv.
Click to expand...

For sure, although it's not a huge issue in my case because I'm not a fan of TV and I have a multifuel burner in the living room so I've got used to having to chop up logs. I get that Rayburns are much hungrier though.

The thermal store is well interesting, thanks. I'm just watching a few vids about them on Youtube. Grey cells are in motion...

I can see from the comments now as to why a zone valve is better. I think it seems that the right Thermal Store would already have the instrumentation incorporated. Initial thoughts, might be better to keep my gas fired sealed heating system too and spend more like a couple of grand on, say, something like this:

http://www.advanceappliances.co.uk/product/70-multi-fuel-universal-thermal-store-sfuts

I'm aware of the need for a heat leak on the gravity circuit.
 
I was initially considering running two separate heating systems, obviously with different radiators. It's an old house and has approx 100 year old L shaped extension which gets particularly cold in the winter. The Rayburn was primarily intended to combat that. The gas heating system otherwise costs a fortune due to the amount of heat loss.
 
If the heat loss is high then it will need a lot of fuel. Whatever that fuel is.

But wood needs working on like cutting logs.

Used to take me 25 min to cut an evenings logs when I went to France .
 
swishy6 said:
I was initially considering running two separate heating systems, obviously with different radiators. It's an old house and has approx 100 year old L shaped extension which gets particularly cold in the winter. The Rayburn was primarily intended to combat that. The gas heating system otherwise costs a fortune due to the amount of heat loss.
Click to expand...
If its a detached property with no mains gas you should qualify for a pellet boiler for free if you look them up.
 
Thermal store looks like a winner. Just pondering whether to look into feasibility of linking with the combi or having a vented gas boiler as the multifuel option. I initially thought that thermal store I linked would do sealed and solid fuel together. More I read the more a vented looks like the option really. Means I don't need to pay that sort of money for the store I guess.
 
I probably need to ring some suppliers. On quick glance it looks like adding a sealed system would require someone with an 'unvented' qualification plus 12 monthly checks. Add to that the Thermal Store will cost almost 2 grand.
 
Cheap option is just have a wood burner for the living room and forget the idea of heating the house.
Leave it to a modern boiler that will do it without any intervention required. Also a lot cheaper to implement.
My own time is valuable so wouldn't want to waste it on chopping wood and filling a solid fuel appliance.
Maybe once in a while I use our open fire place. But more trouble than it is worth.
 
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